Prepared by Powell Smith, Lexington County Extension Agent, and Debbie Shaughnessy, HGIC Horticulture Specialist, Clemson University. (New 02/99. Revised 04/03. Image added 01/09.)
Turnips (Brassica rapa) and rutabagas (B. napus) are generally tolerant of freezing weather, and their roots can be stored for a fairly long period of time in cold storage conditions. Rutabagas or Swedish turnips ("Swedes ") tend to be somewhat larger, sweeter and less strongly flavored than turnips. Also, their flesh is a yellowish creamy color. Turnips have a crisp white flesh and a zesty mustard-like flavor.
Although the leaves of both plants can be eaten, turnip greens are a more common food than rutabaga leaves. Some varieties of turnips are grown for the foliage only and do not produce the swollen root.
Although these crops will stand some heat, they are normally considered cool-weather crops. Plant them in late winter/early spring for a spring crop or in the late summer for a fall/winter crop. The seeds of turnip and rutabaga are very small. The seedlings are fairly small and delicate as well. Scatter the seeds and rake them in or plant them thickly in a straight, narrow line. Cover the seeds about ½ inch deep. Very thick stands will have to be thinned to allow for good root formation. To ensure good germination and emergence, frequent light watering may be needed. Crusty soils will retard emergence and a poor stand may result in these soils.
Piedmont: Abbeville, Anderson, Cherokee, Chester, Edgefield,
Fairfield, Greenville, Greenwood, Lancaster, Laurens, McCormick,
Newberry, Oconee, Pickens, Saluda, Spartanburg, Union and York counties.
Central: Aiken, Allendale, Bamberg, Barnwell, Calhoun, Chesterfield, Clarendon, Darlington, Dillon, Florence, Kershaw, Lee, Lexington, Marion, Marlboro, Orangeburg, Richland and Sumter counties.
Coastal: Beaufort, Berkeley, Charleston, Colleton, Dorchester, Georgetown, Hampton, Horry, Jasper and Williamsburg counties.
Turnips and rutabagas will thrive in many types of soil. A loose, friable loam will allow the best root size and formation. Good drainage is essential, but dry soils should be avoided unless irrigation is planned. Soils of moderate fertility will produce the best crop, although proper fertilization and pH adjustment can overcome lack of natural fertility.
A soil test should be taken to determine the soil pH and nutrients needs. The optimum pH for turnip and rutabaga production is 6.0 to 6.5. Apply limestone according to soil test recommendations at least three months prior to planting to adjust the pH to the proper level.
Soils that are infested with root-knot nematodes should be avoided particularly for the fall crop; these pests will cause deformed roots. Do not plant turnips or rutabagas after other cole crops.
A soil test is always the best method for deter-mining the fertilization needs of a crop. Information on soil testing is available in HGIC 1652, Soil Testing.
If a soil test has not been taken, fertilize turnips and rutabagas with 3 pounds of 5-10-10 fertilizer per 100 square feet. Add additional nitrogen when the young plants begin to put on "true leaves" or after a heavy rainfall. Apply calcium nitrate at 2 pounds per 100 feet of row or 33-0-0 at 1 pound per 100 feet of row. Avoid applying too much nitrogen, which will reduce root formation. Broadcast fertilizer over the whole planting area a few days before seeding. Sidedress applications should be placed at least 3 inches away from the seed row.
If the weather is dry, irrigation during the root development stage will give the best quality roots.
Early season weed control is essential. When rows are used, shallow cultivation and hoeing are effective. In a wide bed, pulling the weeds is sometimes the only solution. This should be done when the weeds are very small. Hoeing and cultivation also keep the soil loose and friable around the plants, enabling them to produce large, well-shaped roots.
Turnip tops can be harvested from a very early stage for greens. Continual harvest of the tops will adversely affect root development. Harvest turnip roots when they reach the size of a tennis ball or larger (2½ to 2¾ inches in diameter).
Rutabagas will get larger if they are planted early enough. They can be eaten at smaller sizes, but start harvesting them when they reach the size of a softball (3 to 4 inches in diameter).
Pithiness and/or a very strong flavor can develop if these crops are left in the ground during hot weather. Also, do not leave them in the ground during hard freezing weather. These roots store well in plastic bags in the refrigerator or in a cold root cellar. Although rutabagas and turnips are normally cooked, many people choose to eat them lightly stir-fried or raw in salads.
Turnips and rutabagas suffer from the same problems as other members of the cabbage group. Several species of leaf-feeding caterpillars eat the foliage. Cutworms can sever the seedling. Wire-worms occasionally feed on turnip roots.
Damping-off, downy mildew and white spot are diseases that will damage turnips and rutabagas.
Excerpted from Home Vegetable Gardening, EC 570, 2002.
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