(Turnip green production is discussed in HIL-16, Greens.)
Turnips and rutabagas are among the most commonly grown and widely adapted root crops. They are members of the Cruciferae or mustard family and belong to the genus Brassica. Turnips are Brassica rapa and rutabagas are Brassica napobrassica. The two are similar in plant size and general characteristics. Turnip leaves are usually light green, thin and hairy, while the rutabagas are bluish-green, thick and smooth. The roots of turnips generally have little or no neck and a distinct taproot, while rutabaga roots are often more elongated and have a thick, leafy neck and roots originating from the underside of the edible root as well as from the taproot.
Turnips and rutabagas are cool-season crops and will make their best root growth during relatively low (40 to 60°F) temperature growing conditions. They can be grown as either a spring or fall crop; however, rutabagas require a longer growing season (90 days) and should be planted as early in the season as possible. Early maturing varieties of turnips can be ready to harvest in 40 days, while late-maturing varieties take up to 75 days.
These crops are biennials, which implies seed production during the second year. However, if an extended period of cool weather occurs after spring-planted turnips or rutabagas are well along in development, they may form seedstalks, which halts root development, ruins successful production and renders them unsalable.
A moderately deep, highly fertile soil with pH 6.0 to 6.5 is best for growing turnips and rutabagas. A soil test should be taken and lime added as needed.
Varieties differ mainly in color and shape of root. There are white- and yellow-fleshed varieties of both crops, although most turnip varieties are white-fleshed and most rutabaga varieties are yellow-fleshed.
Purple Top White Globe -- 58 days from seed; bright purple crown, white below the crown, 5 to 6 inches in diameter, globe-shaped; leaves dark green and cut.
Just Right F1 - 35 to 40 days; white root; 7 to 8 inches in diameter; flattened globe-shaped; light green leaves that are deeply cut. Use only as a fall crop.
American Purple Top -- 90 days; deep purple crown; yellow below the crown; globe-shaped root; 5 to 6 inches in diameter with yellow flesh color; medium size, blue-green, cut leaves.
Laurentian -- 90 days; purple crown; light yellow below crown; globe- shaped roots 5 to 5.5 inches in diameter with yellow flesh; medium blue-green, cut leaves.
Fertilizer applications should be based on soil test recommendations. Commercial grower recommendation for turnips and rutabagas is 40 to 60 lb nitrogen (N), 40 to 60 lb (P2O5) and 60 to 100 lb K2O per acre. Gardener recommendation for turnips and rutabagas is 3 lbs of 10-10-10 per 100 square feet. Apply 1 to 2 lb of boron per acre (gardenders apply 0.5 oz borax per 100 ft2) either in the fertilizer or spray the soluble boron source Solubar.
|Coastal Plain||February 1 to April 15||August 1 to September 15|
|Piedmont||February 15 to April 30||July 15 to September 15|
|Mountains||March 1 to July 1||August 15 to September 15|
* Note: Rutabaga must be seeded roughly 21⁄2 to 3 months before heavy frost.
Multiple rows on a raised seedbed will increase production efficiency per unit of land. Seedbeds can range from 3 to 5 feet wide, depending on planting and cultivating equipment. Seed should be sown 1⁄2 inch deep, and 4 inches in row, in rows 12 to 15 inches apart, which will result in more uniform growth and greater ease of handling at harvest. Approximately 11⁄2 to 2 lb of seed per acre will be required. Thinning is not normally necessary if planted properly, but, if needed, plants should be thinned to 3 or 4 inches apart in the row.
Weeds -- If cultivation is used to control weeds that emerge, it should be shallow (less than 2 inches deep). For herbicide recommendations consult the current North Carolina Agricultural Chemicals Manual or your local county extension center.
Insects -- Turnip aphids, flea beetles, root maggots and wireworms are serious pests. Root maggots and wireworms attack the roots and control requires preplant applications of the proper insecticides to the soil. Aphids and flea beetles damage the tops and a spray program may be needed to control them.
Diseases -- Clubroot, root knot, leaf spot, white rust, white spot, anthracnose and alternaria are several disease problems.
Certain insects and diseases can be controlled chemically, while others may require cultural operations. Consult the current North Carolina Agricultural Chemicals Manual or your county Extension center for specific pest control recommendations.
Turnips and rutabagas require an abundant supply of moisture to insure a high quality product. Most soils will require 1.5 inches of water every 7 to 10 days.
Commercial Growers -- Turnip roots are harvested for bunching when 2 inches in diameter. Turnip roots that will be topped are harvested when 3 inches in diameter. Rutabagas are harvested when roots are 4 or 5 inches in diameter. Turnips with tops are washed and tied in bunches of about four to six plants. Topped turnips and rutabagas for the general market are sold by either volume or weight. Topping is recommended for sales in most wholesale and retail outlets. "Topping" is the removal of the leaves from the fleshy root. The roots are commonly packed in transparent film bags for individual consumers.
Home Gardeners -- Turnip roots are harvested for bunching when 2 to 3 inches in diameter. Turnip leaves can be harvested as single leaves, picked one at a time, or by several cuttings of the tops, taking care to avoid growing points or by cutting all tops at one time. Rutabagas are harvested when roots are 4 or 5 inches in diameter. Harvest before the weather becomes hot, or the roots will become pithy and woody. Harvest fall crops after the first frost, which can sweeten the flavor of the roots. Mulch the growing area heavily and continue to harvest until the ground freezes.
Good average yields of turnips are 300 cwt/acre (gardens 75 lbs/100 square feet) while rutabagas will yield around 400 cwt/acre (gardens 100 lbs/100 square feet).
- Growers - Find a market. (This can be difficult for rutabagas.)
- Select a friable, moderately deep soil.
- Test soil for lime, fertilizer and nematicide (for growers) needs.
- Lime to pH 6.0 to 6.5.
- Choose a recommended variety.
- Plant in time to allow harvest before weather becomes too hot or too cold.
- Irrigate when rainfall is not sufficient.
- Harvest before pithiness begins (about 3- to 4-inch diameter roots).
- Store in a cool, moist place (32 to 35°F and high humidity of 90 to 95%).
* For all pest management recommendations check the latest issue of the NCCVR (North Carolina Commercial Vegetable Recommendations, AG-586) or your county Extension center.
Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by North Carolina Cooperative Extension nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your county Cooperative Extension agent.
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Last modified: Jan. 5, 2015, 1:19 p.m.