“Intensive Vegetable Production” refers to a system of marketing and producing vegetable crops in which great attention is placed on detail and optimization of resources such as land, capital, labor, equipment, transportation to market, and management time. The ojective of such a system is maximum profit for the farm. The system you choose should take into account your location, availability of markets, production seasons, and personal interest. This system differs from most extensive crop production systems because land and other resources are used several times a year, rather than for a short, very active period. An important caution is to reduce the intensity of activity to a measured level throughout the year so that you do not experience burnout.” We suggest that you first find a market for the crops you wish to grow. Then, select crops that can give you a spread of cash flow and labor demands throughout the year.
We suggest that you start with no more than six crops and that these crops mature in different seasons. With experience, you can increase the number of crops as the markets dictate. For example: lettuce in the early spring, snap beans in the late spring, cucumbers for early summer, peppers in early midsummer, tomatoes in midsummer, snap beans again in early fall, and greens or broccoli for late fall and early winter.
Intensive production systems can be very profitable, with a net profit of $5,000 per acre not uncommon. Good planning and attention to the production and marketing practices described in this bulletin can help you attain this level of profit.
Market Planning and Development
Most vegetable growers are quite aware that any income realized from their efforts depends greatly on their marketing success. For intensive vegetable production, growers with good marketing skills–but average production practices–are likely to realize more profit than growers with average marketing skills and good production practices. There is widespread agreement that marketing is important; however, there is less agreement on how to succeed in marketing, even among those individuals who are successful. Marketing vegetables is similar to marketing other agricultural commodities in certain respects. Careful and timely attention to cultural practices is required. There must be a reasonable expectation that the price received will exceed the total per-unit cost. Growers must deliver farm products to buyers at locations, times, and in forms that the buyers want. However, the inability to store vegetables for an extended period of time, the labor required to grow and harvest vegetables, and the extreme variability in prices present unique challenges for vegetable growers. Successful marketing of vegetables requires more individual initiative and close coordination of production, handling, and marketing activities than do most other agricultural commodities.
Most growers go through a nearly intuitive “production potential assessment” prior to planting a crop for the first time to determine its production and financial feasibility. In this process, particular equipment and handling needs are identified. Next, probable expense and yield forecasts are made. Cultivars (horticultural varieties) that can be grown are investigated and cultural practice information is collected. In contrast, "market potential assessments" are usually less complete and often are accomplished simply by making several telephone calls to other growers or perhaps "an expert" to inquire about last year's average price, or by reading trade publication articles. Often, a marking plan is synonymous with identification of a seller. Too few growers develop a sound marketing plan. Key elements in development of a marketing plan are studying market situations and evaluating available opportunities. All available sales options should be identified. It is crucial to deliver the right products in correct containers at the right time to consumers and growers must acquire knowledge about current prices and adjust variety selection, cultural practices, grading standards and packing procedures to satisfy what buyers want. Finally, you should investigate the advisability of extending product shelf life through the use of precooling equipment.
Many growers examine the market window potential of a crop as a starting point in developing a market plan. A market window is defined as the particular period of time during which vegetables can be sold at a profit. Information needed to analyze a crop's market window potential includes historical daily or weekly prices at a particular sales market, a cost-of-production estimate, and an indicator of price volatility. A "window of opportunity" exists to market the crop if expected prices exceed average costs.
Unfortunately, development of a marketing plan and conducting market window analyses will not guarantee marketing success. Many other factors influence marketing success, such as weather, pests, the volume and quality of product available, and grower contacts and relationships with buyers. However, it is prudent for growers to recognize that vegetable production is a risky agricultural venture and substantial financial losses (or profits) can occur. The same motivation exists in thoroughly assessing production or marketing potentials. Try to reduce and manage risks rather than eliminate them.
Produce marketing opportunities are expanding as many consumers have renewed their interest in eating healthful and nutritious fruits and vegetables. During the past decade, total United States per-capita consumption of vegetables increased 25 percent. Consumption levels for selected crops such as broccoli and tomatoes have exceeded this average increase. The trend toward increased consumption of vegetables has been helpful to growers, yet it has also produced changes in buyer and producer interaction. Buyers often need value-added services (such as precooling) and want a more diverse product mix. Most now stress better price-value relationships in their buying practices. Consumer interest has established produce as the premier image-maker in most grocery stores. Industry analysts report that the produce department is the most profitable operation in the typical chain-operated supermarket. Expanded floor space and a doubling in the number of items carried by the average produce department have increased complexities in handling and buying items. Competitive pressures and image concerns also have reduced buyers' willingness to accept items of poor quality.
Intensive vegetable growers in North Carolina usually have one or more of the following sales options: (1) direct sales to consumers through pick-your-own, roadside stand, or farmers' markets; (2) packers and shippers; (3) food service and institutional markets such as prisons, hospitals, and restaurants; (4) direct delivery to independent and locally-owned grocery stores; (5) marketing cooperatives; (6) processors; (7) wholesalers, pinhookers, and truckers; (8) warehouse operations for chain stores; (9) repackers and terminal markets. Produce growers should study all these alternatives and determine those options that are realistic and feasible for their situation. Sales options available to growers often depend on the size of the farming operation and the volume grown, farm location, availability of labor, timing of the harvest window, resourcefulness of the grower, and the customer services provided. All market participants agree that providing top quality improves sales prospects. The concept of quality should include not only cosmetic and grading elements but also service features. Other aspects of quality to many buyers include availability of many lines of vegetables. Extending shelf life by using precooling technologies, reinforced shipping containers, and consistent delivery of uniformly packed vegetables are necessities for all buyers. The service aspects of quality in glutted market conditions can mean the difference between selling and "smelling" (not selling) a crop.
A grower should always be involved in developing a marketing plan, although he or she may elect to employ someone else to handle sales. Listings of brokers, truckers, and sales agents may be obtained from the Blue Book, the Red Book, North Carolina Department of Agriculture & Consumer Services marketing specialists, other farmers, trade publications, and Extension personnel. Remember that "middlemen" specialize in trade and are not necessarily experts in production, credit, and grading.
Preceding sections have emphasized the need to develop an overall marketing plan–considering sales options and production factors–if vegetable farming is to be profitable over time. Limiting factors for most growers involve devoting adequate time and effort to coordinate production and marketing efforts and evaluating their marketing options realistically. Complete development of a marketing plan usually occurs over several years and is refined by "trial and error" methods. But you must start somewhere! Ill-defined marketing terms such as "sufficient volume," "proper grades and containers," and "at the right time" will be more meaningful over time. Increased consumer concerns about the environment and pesticide residues will require even closer linkages between farm management practices and and marketing. Greater emphasis must be placed on coordinating production and marketing efforts so that growers can compete in today's marketplace. Successful intensive vegetable production relies on satisfying buyer wants and needs through coordination of production and marketing activities.
Irrigation Needs and Requirements
Vegetable crops need a uniform supply of soil moisture throughout the growing season. Thus, an irrigation system is essential to successful intensive vegetable production. Irrigation increases yields and allows for a reliable supply of product for market. Vegetables are 80 to 95 percent of water; thus, it might be said that "vegetable growers sell a sack of water and flavor."
The most critical time to irrigate most vegetables is during flower and product development. A water shortage at the time snap beans flower or sweet corn tassels can cut yield by 50 to 75 percent. Another effect of water stress is reduced fruit size in crops such as tomatoes, peppers, and watermelon.
Irrigation sources can be ponds, streams, or wells. A small well can be used to fill a holding pond in areas or low groundwater supplies. A 10-gallon-per-minute well running for 24 hours can pump 1⁄2 acre-inch of water. This is enough water to drip-irrigate 2 to 3 acres daily or to sprinkle-irrigate 3 acres weekly.
Drip irrigation or small sprinkler irrigation is recommended for vegetables. Either of these systems can be used to moisten the soil, stimulate germination, and assure a good stand. Large gun-type irrigation systems produce large droplets that may injure young vegetable seedlings. Also, these systems may pack the soil and reduce soil oxygen–thus hurting many vegetable crops.
A good rule of thumb for vegetable crop irrigation is to apply 1.5 inches of water per week either from irrigation or rainfall. Consider using a tensiometer or soil moisture blocks for more precise water application. The reading on the tensiometer gauge for sprinkler irrigation should be 30 to 40 centibars for sandy soils and 40 to 50 centibars for clay soils. The tensiometer reading for drip irrigation should be 20 centibars for irrigation in sandy soils and 30 in clay soils. The water should be turned off at a reading of 10 in both soils. Drip irrigation should be run daily in hot weather, and at least every other day in cool spring and fall periods. The duration of drip irrigation will depend on soil moisture, but a little irrigation every day yields more uniform plant growth than longer intervals between irrigations.
Drip irrigation is the application of small amounts of water to the soil near plant roots. It should be used frequently to reduce soil moisture stresses. It is important to remember that drip irrigation cannot be used to "catch up" on soil moisture. Drip irrigation can be used alone or in conjunction with plastic mulch.
Irrigation for frost protection is done with sprinklers mounted above or below the crop canopy. The heat lost from the plant part to its environment is replaced by heat released as the applied water changes to ice. As 1 gram of water freezes, 80 calories of heat energy are released. As long as ice is being formed, this latent heat of fusion will provide heat.
Although there is some risk involved, the advantages of irrigation for frost protection are significant. Operational costs are lower because water is much cheaper than oil or gas used in heaters. Irrigation systems are convenient to operate because they are controlled at a central pump house. In addition, there are multiple uses for the same system; e.g. drought prevention, heat suppression, fertilizer application and possibly pest control.
There are some disadvantages. The most important is that if the irrigation rate is not adequate, the damage incurred will be more severe than if no protection had been provided. Inadequate irrigation rate means that too little water is being applied to freeze at a rate that will provide enough heat to protect the crop. The situation is made complex by another property of water–evaporative cooling or the latent heat of evaporation. As 1 gram of water evaporates, 600 calories of heat energy are absorbed from the surrounding environment. When compared to the 80 calories released by freezing, it becomes apparent that more than 7.5 times more water must be freezing than evaporating to provide a net heating effect. Otherwise, the process of evaporation will take energy from plant parts. An ice-covered plant part will cool below the temperature of a comparable dry plant part if freezing stops and evaporation begins. Because wind promotes evaporative cooling, wind speeds above 5 mph limit the success of irrigation for frost protection.
Second, with overhead irrigation, ice buildup can cause plant breakage. Third, overwatering can cause water-logged soils and nutrient-leaching problems. Last, most systems are designed for the worst possible case. This means excess water is applied in most frosts, increasing further the problems of too much water in the field.
The details of designing and operating an overhead irrigation system for frost/freeze protection are contained in the North Carolina Cooperative Extension bulletin Irrigation for Apple Orchards. Several very important points are repeated here. If the capacity of the irrigation system is not sufficient to provide protection under the extreme conditions expected during the night, the system should not be turned on. In general, no system will provide protection in wind speeds greater than 5 mph for tree crops and 10 mph for low-growing crops. A backup power source is essential, because a power failure can be devastating due to the evaporative cooling effect. Once started, irrigation must continue until the ice is melting and loose. This usually occurs soon after the morning sun hits the trees.
Consult HIL-33e, Vegetable Crop Irrigation, for more information on irrigation. Consult HIL-33, Using Plastic Mulches and Drip Irrigation for Vegetables, for drip irrigation information. Consult HIL-105, Low Temperature Protection for Horticultural Crops, for frost-protection system information.
Plastic Mulch Systems
As used in North Carolina, mulching, drip irrigation, and fumigation act in concert to produce yields and vegetable quality that are far superior to those obtained when each input is provided alone. Plastic mulch systems result in twice the yield normally achieved by a good grower, and three- to four-times average yields for muskmelons, strawberries, watermelons, cucumbers, tomatoes and peppers. Yield increase may be even five or six times greater for crops such as eggplant, squash, and okra. The plastic mulch system can increase earliness by 1 to 2 weeks and allows cold-sensitive crops such as cucumbers, okra, and eggplant to be transplanted earlier than without plastic.
Plastic mulch warms the soil, but it also sheds excess rain that may waterlog soil and leach fertilizer. Drip irrigation under the plastic keeps soil moist during drying periods. Fumigation reduces insects, diseases, and weeds but also kills other soil bacteria, thus releasing some nitrogen for young plants. Consult HIL-33, Using Plastic Mulches and Drip Irrigation for Vegetables.
Pest management is key to success for intensive vegetable systems. Growers often have many crops in one field. Insects will be attracted to other hosts just by the proximity of the hosts. Diseases also become greater problems in this system than in a one-crop-per-year system because there is always a crop in the field. Rotating crop families in a field reduces both insect and disease pressures, turning a liability into an asset.
Pest management is achieved by carefully scouting the fields, identifying pests properly, and developing a management strategy. This strategy may be any of the following: (1) taking no action because the pest is not an economic threat; (2) rotating crops to avoid pest buildup; (3) planting trap crops to attract insects away from production crops; (4) separating plantings to prevent older plantings from contaminating younger plantings; and (5) applying a plant protectant material by a high-pressure (>200 psi) sprayer–essential to provide good coverage and adequate reduction of pests.
Extensive information that is crop-specific (scouting manuals, the North Carolina Agricultural Chemicals Manual, etc.) is available from your county Cooperative Extension Center. It is essential to plan for pest management for intensive vegetable production. Be careful not to contaminate adjacent fields with noncleared crop protectants. Careful use of crop protectants can go a long way toward agricultural and financial success.
Row Spacing, Multiple Rows Per Bed, and Equipment Uniformity
It is important to select a single row spacing that makes optimum use of your equipment. Choose either 5, 6 or 6.25 feet between rows and adjust the numbers of rows per bed, depending on the crop. Here are some suggested row numbers per bed or width of the tractor for various crops with optimum spacing for the plastic mulch system (*) and the bare-ground system (+):
- One row on a wide bed: muskmelons+*, watermelons+*, cucumbers, tomatoes+*, eggplant, asparagus+, summer squash, winter squash+* and pumpkins+*.
- One row with narrow beds: broccoli, cabbage, cauliflower+, collards, greens, snap beans+, southern peas+, peppers+, eggplant+, okra+, summer squash+, lima beans+, sweetpotatoes+, potatoes+, and sweet corn+*.
- Two rows on a wide bed: peppers*, cabbage, broccoli, greens, cauliflower*, collards, snap beans, southern peas, lima beans, okra*, eggplant*, cucumbers*, sweetpotatoes, potato, and sweet corn* (rows should be spaced 12 to 15 inches apart if drip irrigation is used).
- Two rows per bed with two narrow beds: broccoli+, cabbage+, collards, lettuce+, greens, snap beans, lima beans, carrots, beets, dry or green onions, turnip roots or greens, and rutabagas.
- Three or four rows per wide bed: greens, carrots+, beets+, lettuce*, dry or green onions, lima+ and snap beans+ (with machine harvest), turnip roots+ or greens, and rutabagas+.
- Five or six rows per wide bed: greens+, carrots, beets, lima and snap beans (with machine harvest), dry+ or green onions+, turnip roots or greens+, and green peas+.
In-row spacings are as important as between-row spacings. Plants should be kept as close as possible to obtain optimum economic returns. Here are some recommended in row spacings for various crops:
- 1 inch - fresh market carrots and green onions.
- 2 inches - snap beans, processing carrots, lima beans, southern peas, green peas, beets and greens.
- 4 inches - dry onions, direct-seeded broccoli, turnip roots, rutabagas, and greens.
- 6 inches - snap beans and lima beans in wide beds, cucumbers+ and asparagus+.
- 8 to 10 inches - sweetpotatoes, potatoes, peppers*, lettuce*, collards, cucumbers*, sweet corn, cabbage transplants, and brocoli transplants.
- 12 inches - okra, peppers+, and summer squash+.
- 18 inches - eggplant+*, muskmelons+*, tomatoes+*, summer squash*, winter squash+*, and pumpkins*.
- 24 inches - watermelons* (if one can sell 12-18-pound melons along with 18+ pound melons).
- 36 inches - watermelons* (if one can sell 18+ pound melons).
- 48 inches - watermelons+ and pumpkins+.
Transplant production is critical to an intensive vegetable system. You need the right cultivar at the time you have scheduled it for your market and your labor. Thus, it is wise to grow your own transplants or have them grown locally. Then you will know that you have the cultivar of your choice, and that it will be ready when you and your field conditions dictate. You can hold plants back until weather conditions become appropriate if you have your own production facility. It is best to use containerized transplants because these plants sustain the least transplant shock. Use some large container sizes (3 to 4 inch) for the first planting if early markets have better prices or a crop is a companion to some other crops (for example, early tomatoes with late strawberries). Large container transplants usually result in earlier (7-to 14-day) production. Consult AG-37, Commercial Vegetable Transplants.
Succession Planting and Multicropping Schemes
It is important to harvest a crop over a long period of time for intensive vegetable production. This allows you to develop consistent supplies and purchases by retail or wholesale customers. Having a particular item for sale over a long period of time enhances loyalty in customers and provides them with a service so they need to come only to you for that item. Sometimes it may be necessary to grow one crop at cost or less in order to sell other crops.
For example, some markets that sell greens want collards, turnips, mustard, and kale in every shipment. Spring collards require more time to mature; thus, some growers transplant collards at a higher expense just to be able to sell these other crops–with positive results. Customers often reply on you for "one-stop shopping." You need to supply as many items as you can in order to get their business and keep them coming.
You need to start early for a long season of supply. Various practices that enhance earliness are large transplants, planting early with large containers, planting several times on the same row (in case frost kills the first plantings), using plastic mulch, using rowcovers and hot caps, bedding, sloping beds to the south, running rows east and west, and installing windbreaks. Consult AG-133, How to Grow Early Vegetables, for further details.
Often you can increase production by growing fast-growing crops and slow-growing crops on the same bed. The fast-growing crop matures before the slow-growing crop begins to compete with it. Here are some examples:
- Tomatoes in the center and two rows of transplanted leaf or Boston lettuce with plastic mulch.
- Eggplant in the center and two rows of transplanted leaf of Boston lettuce with plastic mulch.
- Tomatoes in the center and two rows of transplanted bok choy with plastic mulch.
- Eggplant in the center and two rows of transplanted bok choy with plastic mulch.
- Radishes interseeded between turnips, carrots, and green onions.
- Muskmelons on plastic with a row of sweet corn in the same plastic.
Succession cropping is a particularly important component of the intensive vegetable system. You can maximize use of your resources to increase profit and achieve the $5,000 net profit per acre that is possible with this system. It takes timing and planning to maximize your land, equipment, labor, and marketing resources.
If you are a new user of the intensive system, you should specialize in four to six crops the first year and plan to have these crops on the market as climate permits. But don't be foolish! For example, it is not practical to grow snap beans for August 1 harvest in the coastal plain. Use knowledge of your climate to schedule plantings so that as harvesting of the first planting is ending a second planting is adding to production. Some crops respond to temperature and can be scheduled following degree-day models. Consult AG-236, Growing Degree Days for North Carolina, for more complete information.
Succession cropping can also mean following the first crop with another compatible crop. Here are some examples of such systems. Let your market opportunities dictate your choices:
- Strawberries on plastic mulch and drip irrigation, then killed with an herbicide, followed by muskmelons, pumpkins, watermelons, cucumbers, a fall planting of summer squash or winter squash, eggplant, tomatoes, cabbage, cauliflower, broccoli, collards or sweet corn, without removing the plant trash, or all of the above crops with hand-removal of the first crop trash and lettuce.
- Peppers or tomatoes followed by muskmelons, pumpkins, watermelons, cucumbers, fall summer squash or winter squash, eggplant, cabbage, cauliflower, broccoli, collards, sweet corn, okra, or lettuce. Stakes will be removed, the crop mowed, and a herbicide applied.
- Any spring vine crop followed by muskmelons, pumpkins, watermelons, cucumbers, fall summer squash or winter squash, eggplant, tomatoes, cabbage, cauliflower, broccoli, collards, sweet corn, or okra.
Your objective should be to have your land producing as much as you can grow and to harvest and market throughout the year. This will allow you to spread labor, equipment, and marketing time demands over more of the year and reduce the personal and personnel stress that results from all crops aimed at a single, high-priced market.
In October (except in the mountains), begin with seeding onions, greens, overwinter cabbage, and continue harvesting fall greens, snap beans, summer squash, winter squash, tomatoes, peppers, eggplant, broccoli, cabbage, cauliflower, lettuce, and pumpkins.
In November (except in the mountains), continue harvesting fall greens, snap beans, summer squash, winter squash, broccoli, cabbage, cauliflower and lettuce.
In December (except in the mountains), continue harvesting fall greens, broccoli, cabbage, cauliflower, and lettuce.
In January and February, spring-seed fresh-market carrots, beets, onions, greens, and start transplants of cabbage.
In early February, seed second plantings of fresh-market carrots, beets, onions, greens, and start transplants of large containers peppers, leeks, and lettuce.
In late February, seed third plantings of fresh-market carrots, beets, onions, greens, and lettuce and start transplants of large container tomatoes and eggplant.
In March, seed sweet corn, snap beans, and summer squash on plastic with rowcovers and start transplants of tomatoes, peppers, eggplant, cucumbers, watermelons, and muskmelons.
In April, continue seeding summer squash, cucumbers, watermelons, muskmelons, oriental vegetables, lettuce, snap beans, lima beans, and sweet corn and field transplant cucumbers, watermelons, muskmelons, and okra.
Through mid-May, continue seeding summer squash, cucumbers, watermelons, muskmelons, oriental vegetables, lettuce, snap beans, lima beans and sweet corn and start field seeding cucumbers and okra and field transplant cucumbers, watermelons, muskmelons, and okra.
Raised Beds and Bed Forming
Often two and occasionally three inches of rain from an afternoon thunderstorm will occur in a climate such as North Carolina's. You need to be prepared for excess water. Raised beds will help you to (a) protect plants from these excesses, (b) result in warmer soil (2 to 8°F) that hastens germination and crop growth, and (c) reduce the distance one must stoop for harvest. The soil will be warmer if beds are run east-to-west. The top of the bed should be sloped to the south because additional warmth is provided by taking advantage of the angle of the sun.
Raised beds can be obtained by using single- or double-disk colters, row middle sweeps, rolling cultivators, middle buster plows, or opposing moldboard plows. Bed height may vary from 4 to 8 inches, depending on the crop and the needs for water removal. The soil should be leveled to even out hills and valleys in the top of the bed. This can be done with a board or metal plow on the seeder or transplanter, but a better method is to use an extruded bed shaper. This bed shaper draws the soil through a wide opening in the front and forces it through a smaller opening in the back to firm the extruded soil, much like a sausage maker. A "Super Bedder" is often used for beds with plastic mulch. This machine gathers more soil than traditional bed shapers–from the entire 5 or 6 feet between rows–and helps to force it through the extruded bed shaper; thus making more uniform beds. Beds for plastic mulch should have a slight crown (one inch higher in the center) to help shed water and eliminate puddling on top of the bed.
The soil is made more uniform in firmness by bed shaping; thus, seedlings can be more uniform. Transplanting will be more even because there will not be holes or hard spots in the bed. Bed shaping simply adds uniformity to the entire operation.
Windbreaks and Drive Rows
Windbreaks and drive rows are important considerations in an intensive vegetable production system. Use of windbreaks can result in increased yield and earlier crop production by providing wind protection. Use of planted drive rows can provide weed control, reduced water and wind erosion, and physical support for heavy equipment moving through the field. This latter benefit can be critical in maintaining a good pest control program when soils otherwise would be too wet.
Young plants are most susceptible to wind damage and "sand blasting." Rye strips between rows can provide protection from wind and wind-borne sand. Windbreaks can improve early plant growth and earlier crop production, particularly with melons, cucumbers, squash, peppers, eggplant, tomatoes, and okra.
The major benefit of a windbreak is improved use of moisture. Reducing the wind speed reaching the crop reduces both the direct evaporation from the soil and the moisture transpired by the crop. This moisture advantage also improves conditions for seed germination. Seeds germinate more rapidly and young plants put down roots more quickly. Improved moisture conditions continue to enhance crop growth and development throughout the growing season.
The type and height of the windbreak determine its effect. Windbreaks can be living or nonliving. Rye strips are suggested for intensive vegetable production based on economics. In general, the windbreak has a significant effect on the crop at a distance of eight times the height of the windbreak. A rye strip three feet tall will "protect" vegetables up to 24 feet away. The windbreak should be planted perpendicular to the prevailing wind direction. Rye strips should be drilled from September through October to obtain good plant establishment and to provide adequate time for plant growth prior to beginning the next production season.
Precision seeding has many advantages for the vegetable grower, but it is not a substitute for good management. Precision seeding simply reduces the cost and increases the reliability of crop production.
Some of the advantages of precision seeding are:
- Reduced seed costs. Only the seed that is needed is sown.
- Greater crop uniformity. Each seed is spaced equally, fewer harvests are necessary, and/or greater yield is obtained at harvest.
- Improved yields. Each plant has an equal chance to mature; yields can increase 20 to 50 percent.
- Improved plant stands. Seeds are dropped shorter distances, so they scatter less and have a uniform depth of planting.
- Thinning can be reduced or eliminated.
Some of the disadvantages of precision seeding are:
- Seedbed preparation is critical.
- Seed must be more vigorous–each seed must emerge and does not have the benefit of mass action to break soil crusts.
- More management is required.
- Equipment costs more.
- Planter parts may not be readily available locally because there is a limited demand for these parts.
There are six types of precision seeders:
Belt type – represented by the StanHay seeder. Circular holes punched in a belt accommodate the seed size. Holes are spaced along the belt at specified intervals. Coated seed usually improves the uniformity obtained with this type of seeder.
Plate type – represented by the John Deere 33 or Earth Way. Seeds drop into a notch in a horizontal plate and are transported to the drop point. The plate is vertical in the Earth Way and catches seed in a pocket in a plastic plate. Most spacing is achieved by gearing the rate of turn of the plate.
Vacuum type – represented by the Gaspardo, Heath, Monosem, StanHay, and several other seeders. Seed is drawn against holes in a vertical plate and is agitated to remove excess seed. Various spacings are achieved through a combination of gears and number of holes per plate. Coated seed should not be used in these planters.
Spoon type – represented by the Nibex. Seed is scooped up out of a reservoir by small spoons (sized for the seed) and then carried to a drop shoot where the spoon turns and drops the seed. Spacing is achieved by spoon number and gearing.
Pneumatic type – represented by the International Harvester cyclo planter. Seed is held in place against a drum until the air pressure is broken. Then it drops in tubes and is blown into the soil. This planter is recommended only for larger vegetable seed.
Grooved cylinder type – represented by the Gramor seeder. This seeder requires round seed or seed that is made round by coating. Seven seeds fall from a supply tube into a slot at the top of metal case into a metal cylinder. The cylinder turns slowly. As it reaches the bottom of the case, the seeds drop out of a diagonal slot. The seed is placed in desired increments by a combination of forward speed and turning rate. This planter can be used with seed as small as pepper seed. It works best with coated seed.
Before you purchase a precision seeder, be certain that all other aspects of crop production are being managed properly. Precision seeding requires good seedbed preparation to provide a uniform environment for the seed to swell, germinate, and emerge. Bed shaping is generally considered essential for precision seeding. Irrigation is also important because lack of moisture may stall or stop seedling emergence and reduce uniformity.
High-quality seed should be purchased. Precision seeding is no substitute for uniform germination.
Control of weeds and other pests is critical with precision seeding. Fewer seeds are used compared to conventional seeding, and the added cost makes seedling survival extremely important.
Speed of planting depends on the seeder. Operation of a seeder above recommended speeds results in reduced uniformity, seed scatter, and even poor stands in some instances.
Weed management in an intensive vegetable production system is a multistep process involving weed identification, and cultural, mechanical, and chemical methods of weed control. An intensive vegetable production system is not an efficient user of soil moisture, soil nutrients, sunlight, or other factors used for growth without a properly timed and implemented weed management program.
Methods of weed control
Cultural methods of weed control. Select production fields carefully and match your crops with fields based on weed species and level of infestation. Less-competitive crops such as lettuce and onions should be planted in fields with less-competitive weeds and low weed populations. Table 1 ranks crops based on their ability to compete with weeds. It is a revised ranking from the Growers Weed Management Guide by H. M. Kempen (available from Thomson Publications).
|Pumpkins and all squash||Tomatoes|
|Sweetpotatoes||Vegetable transplant beds|
Production practices used in intensively produced vegetables should be based on sound recommendations. This is important because crops with good vigor (plant growth and development) compete with and greatly suppress weeds. The latest production recommendations are available in Horticulture Information Leaflets and crop bulletins at your local N.C. Cooperative Extension center.
Critical weed-free periods to prevent yield or quality reduction in vegetables generally range from 2 to 6 weeks after planting. Information on specific crops can be found in the Weed Attack Manual available from the Department of Horticultural Science at NC State University.
Chemical weed control. Preemergence herbicides should be applied prior to weed emergence to suppress weeds. Herbicides applied before emergence give better weed control when rain or irrigation is received soon after application. Wetting the soil 1.5 to 2 inches deep is usually enough to activate most herbicides. Information regarding when irrigation or rain should occur is on the herbicide label and in the North Carolina Agricultural Chemicals Manual. Postemergence herbicides, if available, are options to kill emerged weeds. Timing is especially important because these herbicides kill small, actively growing weeds but are often ineffective with large or environmentally stressed (drought, excessive moisture, etc.) weeds. Some postemergence herbicides require adjuvants (a crop oil or surfactant) for optimum activity. Refer to the label for information regarding adjuvants. (Note: Follow all rotation guidelines on the herbicide label to prevent herbicide injury to follow-up crops.)
Nonchemical weed control. Nonchemical methods of weed control are important in intensive vegetable production systems. Plastic mulch can be used in many vegetable crops to enhance crop growth and suppress weed growth. When considering weed suppression only, black, green Infrared Transmitting Film (IRT), or clear plastic film give excellent, good, and poor weed suppression, respectively. Limited research has also shown that green IRT film gives good control of yellow nutsedge. Shredded newspaper and grain straw can also be used to suppress weeds. Shredded newspaper gives good weed control at the rate of 2.5 to 3 bales per 20 feet of row. Wheat straw at the rate of 2 to 2.5 bales per 20 feet of row gives good weed control, but volunteer wheat seedlings should be controlled chemically or removed by hand if they emerge. Emerged weeds should be killed prior to application with either mulch (newspaper or wheat straw).
Cultivation to kill emerged weeds in vegetable crops is one of the most-effective means of killing weeds. Certain crops, such as peppers and onions, respond favorably to cultivation even if weeds are not present. Cultivation should be done as close to the crop row as possible without injuring the crop plants. Emerged weeds that are less than 1.5 to 3 inches tall are usually the easiest to kill by cultivation. For close cultivation, gauge or guide wheels allow for precise guiding of the cultivator. There are several types of cultivators including sweep, rotary tiller, and rolling or knife type. Sweep cultivators are the most effective for large weeds, but care must be taken not to bury the crop with soil. These cultivators, fitted with half-sweeps or fenders, will reduce this problem. Rotary tiller cultivators are effective on small weeds and reduce soil crusting or flaking but are less effective on small weeds and are useful when beds need reshaping but are not effective on large weeds. Knife cultivators are effective in cutting through the soil, encouraging development of long and straight roots in crops such as carrots. Knife cultivators are not very effective in fields with heavy weed pressure, so they should be used when weeds are small.
Managing labor is one of the most important functions a producer performs, but it is one of the most complex and frustrating aspects of the farm business. These frustrations arise because of the multiple activities involved in recruiting, interviewing, training, and motivating farm labor. Many farmers feel inadequate managing farm labor and may view the function as a waste of time and an annoyance. Managing farm labor successfully requires time and effort. It is probably more important to the success of a farm business than shopping for the right truck or tractor. Therefore, expending the time and effort on labor management commensurate with its importance to the farm business is well worthwhile.
Recruit for success
Often the recruitment, screening, and hiring process is a neglected area in labor management. Have you ever heard a farmer say that the neighbor down the road seems to have all the luck when it comes to finding good farm labor? The person making this statement should realize that, to attract good farm labor, some guidelines must be followed:
- Know yourself. This may seem elementary, but it is a very important aspect of labor management. Are you the kind of person you would like to have as a boss? Are you respected by your employees? Are you a good teacher? Are you a good listener?
- Know your business. Be aware of your business objectives and identify specific goals you expect to accomplish through your employees. Know what role each new employee will play in the success of your business. Also know the financial strength of your farm business and what impact the new employee can have on this financial position.
- Sell (market) the job opportunity. Success in recruiting is likely to be affected by the recruiter's attitude toward and enthusiasm for this task. A professionally written job advertisement will enhance the pool of applicants. A well-thought-out job description and a written interview schedule will facilitate the interviewing process and describe the job clearly to all applicants.
Maintaining a labor force
An aspect of labor management that is a close second is importance to the recruitment of good labor is that of maintaining a labor force once it is hired; that is, reducing labor turnover. The following processes are essential in maintaining a labor force.
- Provide adequate training. Inadequate instruction and training frequently result in worker frustration, poor job performance, and a stressful working relationship between employer and employee. Good worker instructions and proper training can increase worker output, reduce production costs, improve product quality, and improve employee morale.
- Conduct performance reviews. A performance review is an opportunity for both employer and employee to evaluate how well the the employee is performing his or her job responsibilities. The performance review also provides an opportunity for both parties to discuss actions to be taken to improve job performance, working conditions, or other matters of mutual concern. A written performance evaluation instrument is extremely beneficial.
- Understanding human motivations. Motivating people can simply be defined as getting people to do what you want them to do–not because they have to, but because they want to. A major factor influencing worker motivation is whether or not the job satisfies some of the worker's needs.
Individual needs can be classified into two categories: (1) basic or maintenance needs, and (2) motivational needs. It is important to be aware that these categories apply whether one fills the role of manager/employer or worker/employee. Everyone has both types of needs. Basic or maintenance needs include: (1) food, clothing, shelter; (2) safety, job security; (3) social belonging; and (4) status and reputation. Motivational needs include: (1) growth in knowledge and skills; (2) achievement; (3) sense of responsibility; and (4) recognition. A worker often becomes dissatisfied and has little enthusiasm for his or her work if maintenance needs are not met. Therefore, when the major concern of individuals is food and clothing for themselves and their families, little is to be gained by discussing more responsibility or building equity in the business with these people. However, discussing these items with individuals who have fulfilled all their maintenance or basic needs may prove to be a motivating influence. Obviously, what motivates one employee may not motivate other employees.
A fundamental principle that should become apparent from an understanding of employees' needs is that higher wages and more benefits will not necessarily solve all worker motivation problems. An employer who restricts motivation concerns solely to wages is likely to be disappointed in the results. Some highly motivated employees may be more concerned with personal recognition of their performance with a minimal increase in wage. These employees may be seeking the more difficult tasks rather than easier ones or they may want to work more rather than fewer hours. Of course, these are the workers whose primary concern is not fulfilling a basic need (that is, food and clothes), but rather the need for praise and recognition.
Personnel management is a demanding, time-consuming, and complex job. As in any other aspect of running a business, you may need to acquire new skills, implement advance planning, and pay attention to the business on a daily basis if success is to be achieved. You will need to understand how additional labor benefits your operation. Employees and managers must also understand themselves–their goals as well as their strengths and weaknesses as they relate to their managerial position. They must also develop skills in recruiting, interviewing, and motivating the people for whom they are responsible if they are to attract and keep good labor.
Postharvest Quality Maintenance and Market Preparation
Producing the consistently high-quality produce that spells success in a highly competitive market does not stop at the end of the row. The ability to deliver a quality product to the market, and ultimately to the consumer, commands buyer attention and gives the grower a competitive edge. It is important that the product be selected, sized, cleaned, packaged, and cooled according to buyer specifications. Often USDA grade standards are used, but many wholesale buyers want grades better than these. It is important to know what the buyer wants. Proper postharvest cooling and handling can help to ensure that quality is maintained until the product reaches the consumer.
Postharvest cooling rapidly removes field heat from freshly harvested commodities before shipment, storage or processing and is essential for most perishable crops. Proper postharvest cooling can:
- Suppress biochemical degradation and respiratory activity (softening)
- Slow or inhibit water loss (prevent wilting)
- Slow or inhibit the growth of decay-producing microorganisms (molds and bacteria)
- Minimize the product's reaction to ethylene (a naturally occurring ripening hormone that causes aging)
Postharvest cooling also provides marketing flexibility by making it possible to market at the optimum time. Being able to cool and store produce eliminates the need to market immediately after harvest.
It is necessary to understand the basic principles of cooling to select the best cooling method. The choice of cooling method depends on the following factors:
- The nature of the product. Different types of produce have different cooling requirements. For example, strawberries and broccoli require near-freezing temperatures whereas summer squash or tomatoes would be damaged by such low temperatures. Likewise, because of problems that can be caused by wetting of certain products, hydrocooling or icing may not be appropriate.
- Product packaging requirements. The best choice of cooling method may depend on whether the produce is in a box, bin, or bag. The package design can have an effect on the method and rate of cooling.
- Product flow capacity. Some methods of cooling are much faster than others. If the volume of produce to be cooled per season, per day, or per hour is large, it may be necessary to use a faster cooling method than would be used for lower volumes.
- Economic constraints. Construction and operating costs vary among cooling methods. The expense of cooling must be justified by high selling prices and other economic benefits.
Common produce cooling methods
Room cooling is simply a matter of placing produce in an insulated room equipped with refrigeration units to chill the air. It may be used with most commodities, but may be too slow for some that require quick cooling, such as broccoli or sweet corn. It is effective for storing precooled produce but, in some cases, cannot remove field heat rapidly enough. Directing the output of the cooling system evaporator fans carefully can improve the cooling rate significantly. Designed properly, a room cooling system can be relatively energy efficient.
A cooling room that is used only to store previously cooled produce requires a relatively small refrigeration unit. However, if it used to cool the produce, a larger unit is needed. Consult a refrigeration contractor or your Cooperative Extension center to determine the correct size of the refrigeration unit.
Forced-air cooling is used in conjunction with a cooling room and can be used effectively on most packaged produce. Additional fans are used to pull cool air through the packages of produce to increase the cooling rate. The cooling rate depends on the air temperature and the rate of airflow through the packages. This method usually is 75 to 90 percent faster than room cooling. It may be necessary to increase the size of the refrigeration unit to accommodate the additional cooling load when forced-air cooling fans are added to an existing cooling room.
Hydrocooling can be used on most commodities that are not sensitive to wetting. Chilled water flows over the produce, removing heat rapidly. Water removes heat about 15 times faster than air at typical flow rates and temperature differences.
Top or liquid icing may be used on a variety of commodities. In the top icing process, crushed ice is added to the container over the top of the produce by hand or machine. For liquid icing, a slurry of water and ice is injected into produce packages through vents or handholds without depalletizing the packages or removing their tops. This method works well with commodities that have a high respiration rate, such as sweet corn and broccoli.
Evaporative cooling is an effective and inexpensive means of providing a lower temperature atmosphere with high relative humidity for cooling produce. It is accomplished by misting or wetting the produce in the presence of a stream of dry air. Evaporative cooling works best when the relative humidity of the air is below 65 percent. At best, however, it reduces the temperature of the produce only 10 to 15°F and does not provide consistent and thorough cooling.
Produce should be picked during the coolest parts of the day and kept in the shade away from direct sunlight. Many growers in the Western states have found that harvesting at night, "under the lights," is a good way to reduce the amount of mechanical cooling needed in extremely hot weather.
Various information leaflets on specific crops and cooking procedures available from your Cooperative Extension center. Your county agent has a computer program called "Precool Advisor" that will be helpful in choosing the best cooling system for your operation. It considers volume, market, and the economic return to assist in the selection of the system most suitable for you.
|Commodity||Suitable cooling method(s)||Optimum temperature (°F)||Freezing temperature (°F)||Optimum humidity (percent)||Storage life|
|Asparagus||H, I||36||31||95-100||2-3 weeks|
|Beans, snap||R, F, H||40-45||31||95||7-10 days|
|Beans, butter||R, F, H||37-41||31||95||5-7 days|
|Beets, topped||R||32||30||98-100||4-6 months|
|Cabbage||R, F||32||30||98-100||1-6 months|
|Cucumbers||F, H||45-50||31||95||2 weeks|
|Eggplant||R, F||46-54||31||90-95||1 week|
|Green onions||H, I||32||30||95-100||3-4 weeks|
|Leafy greens||H, I||32||30||95-100||1-2 weeks|
|Okra||R, F||45-50||29||90-95||7-10 days|
|Peas||F, H||32||31||95-98||1-2 weeks|
|Peas, field||F, H||40-41||30||95||6-8 days|
|Peppers||R, F||45-50||31||90-95||2-3 weeks|
|Potatoes||R, F||38-40||31||90-95||5-8 months|
|Squash||R, F||45-50||31||95||1-2 weeks|
|Sweet corn||H, I||32||31||95-98||5-8 days|
|Tomatoes||R, F||45-50||31||90-95||1 week|
|R = room cooling, F = forced-air cooling, H = hydrocooling, I = icing
CAUTION: Certain commodities may sustain appreciable chill damage at temperatures 10-20°F above the freezing temperature.
Source: USDA Handbook No. 66
Other steps for maintaining quality
Refrigerated transportation vehicles are not designed to remove field heat from produce. At best, they can only maintain the temperature at which the produce was loaded. Growers, shippers, and truckers can contribute to better produce temperatures and hence fewer losses during transport by following these guidelines:
- Precool trailers before loading them, especially in warm weather.
- Measure and record the products's temperature during loading.
- Keep the trailer and refrigeration unit in good repair.
- Load the produce in a way that will ensure maximum air circulation.
- Keep transit times to a minimum.
Table 2 summarizes postharvest cooling requirements for most of the commodities in the southeastern United States.
Container selection is a very important part of marketing and quality maintenance. Horticulture Information Leaflet 31 lists commonly used containers for various vegetable crops.
Postharvest quality maintenance is very important to intensive vegetable systems. There will be more high-quality produce to sell and it will remain in marketable condition for a longer time if quality maintenance is done correctly. Once vegetables are harvested, quality loss can only be delayed - not prevented.
Communication Needs and Suggestions
Communication is vital to successful marketing. If you are selling wholesale, you need to discuss with your buyer what you grow, when you will deliver it, how you will deliver it, what container you should use, and the definition of quality expectation by the buyer. You should discuss these topics before planting early in the season, during the harvest season, and at the end of the season. The need for communication is constant.
Retail sellers should let the customers know what you will have this year and when it will be available. It helps to advertise a week or so ahead of time what to expect next week. Providing your customers with what they want in quality, product, container size, and variety could help you increase sales. Also, customers might suggest additional items for you to grow.
Communication with your staff is important. Let them know the job requirements. Make your directions clear and concise. Check back on your helpers to find them doing things right and praise them for it. Make sure the staff understands that communication should be mutual, and solicit their opinions. Satisfactory performance should be rewarded adequately.
Your schedule of availability should be organized, and known to employees, customers, and family members. Several additional methods of communication (telephone, fax, cellular phone, and radio) should be used whenever possible.
In intensive vegetable production systems it is almost as important to destroy crop residue as it is to plant the crop. Rapid, complete crop destruction when harvest is over should reduce future insect, disease, and weed pressures. Mow and/or spray a herbicide on the crop as soon as you are done harvesting if you are using plastic mulch.
Plant an appropriate cover crop at the end of the season, or when the land will be vacant for a month or more. Austrian winter peas or crimson clover are good over-wintering cover crops if you are planting in late March or late April, respectively. Rye or wheat are excellent cover crops. Wheat will not produce excessive growth that would be difficult to till into the soil. Sudex or sudangrass is an excellent summer cover crop that produces lots of biomass and establishes itself quickly. Keeping a cover crop on the land when it is not in use will retain more of the soil nitrogen and will increase soil organic matter.
Planning for Next Year
Planning is an important part of intensive vegetable production systems. You should be planning for next year as soon as you start this year's crop. Evaluate what you did, what was good, and what improvements can be made for future crops. Take notes during the season.
Market considerations are extremely important in the planning process. Timing, quality, packaging, variety, and quantity are all very important aspects of planning.
Water source and availability must be considered. Acreage planted should not exceed the supply of suitable water. Water runoff and pollution must also be considered.
Labor supply will govern what you can harvest and when. Reduce the volume of high-labor demanding crops if labor is short.
Pest pressure could determine what crops you can grow successfully. Sometimes rotations must be practiced to reduce weed, insect, or disease populations. Some plant protectant chemicals are ineffective on certain pests, or pests develop resistance to some pesticides. Rotation often breaks a pest's escape of the management procedure.
Very popular cultivars often are not available if ordered late. Good planning will enable you to have the cultivars needed.
Planning is important in choosing crops that have compatible crop protection procedures. Choose herbicides for use in the spring that will not cause damage to a crop planned for fall. Also, be sure that adjacent crops are not affected by drift of crop protectants used in neighboring areas.
A good way to plan is to lay out your farm on a sheet of paper, write in the crop that is to be grown in each field during each month, and list the planned crop protectants, duration of the crop, and the amount of labor to harvest it. This could help you find errors in your plan. Use the computer programs "Budget Planner" and "Crop Planner" at your Cooperative Extension Center. The former will help you determine if a crop and planting date will be profitable for you. The latter will help you find the right selection of crops for your situation and will tell you the risk involved each system. You can try several different situations with Crop Planner to maximize your profit or minimize your risk. You can also learn what input you will have to adjust to meet your market demands.
Intensive vegetable production systems can be very profitable if attention is given to all aspects of culture, marketing, and labor relations. Here are some critical factors to consider:
- Find a market before you plant the first seed, and develop a marketing plan.
- Be prepared to irrigate all your vegetables. Irrigation is a must at seeding to get a uniform stand and a crop that matures on schedule, to activate herbicides and reduce weed problems, to keep the crop growing so it can be delivered on schedule, and to assure good quality.
- Plastic mulch and/or drip irrigation increase yields of most crops. Both also increase earliness and uniformity of most crops.
- Be able to spray for insects and diseases with either a high-pressure sprayer (200 psi or more achieved with a piston or diaphragm pump) or a mist blower for small plots.
- Decide on one row center spacing, usually 60 to 82 inches, to accommodate most vegetable crops.
- Use narrow tires (6 inches wide) on the tractor for cultivation and spraying to get more per unit of land and reduce damage to crops.
- If you plant to transplant crops, grow your own transplants, which will require a greenhouse or coldframe.
- Plan to make several plantings of several crops for as long as it is profitable. It is best to plan to have crops 12 months a year.
- Plan to plant a small amount of several crops (do not plant more acres than you can handle) and do a good job on what you plant. Do not plant so much at any one time that you get overloaded and "burned out" for later crops from which you might make even more money than on early crops.
- Plan for second, third, and fourth crop on each acre.
- Plant on raised beds, which provide good drainage and warm sooner in the spring.
- Grow multiple rows per bed appropriate for the crop.
- Remember that narrow rows increase a crop's ability to compete with weeds and generally reduce weed problems.
- Use narrow rows to produce higher yield per acre and to reduce cost per unit produced.
- Use drive rows to aid getting out of the field.
- Use precision seeding - even small garden seeders made of plastic do a reasonable job of accurate seed placement. Precision seeding will reduce thinning costs.
- Cultivate when weeds are small and easiest to kill.
- Cultivate shallow, so minimum root damage is done. This can be done by a "bunting cultivator," a properly adjusted rototiller or rolling cultivator, or sweeps.
- Have a labor management plan, with someone responsible for each crew. Pay that person for this responsibility.
- Pick crops that do not wilt rapidly in the afternoon; for crops that will wilt rapidly, harvest just before going to market.
- Pack where it is most efficient and where you can control quality the best; for some crops this will be in the field and for others it will be in the pack shed.
- Set up grading, washing, drying, and packing lines to increase your efficiency.
- Wash all root and leaf crops.
- Plan to ice crops if appropriate.
- Deliver as soon as reasonable after harvest, and cool when possible (it will pay in increased prices and acceptance).
- Deliver quality, and communicate with your buyer about your quality each day so there are no misunderstandings.
- Clean up fields as soon after harvest as possible. This reduces weed, insect, and disease problems for the next crop.
- Advise your chemical supplier of what pesticides you expect to need so when a problem arises you can both be ready for it.
- Remember: "You are playing the buyers' game: If you don't like the rules, you can't play!" It's as simple as that.
- Contact your county Cooperative Extension center for further assistance.
Publication date: Jan. 1, 1997
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