Purple Top Turnips 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 these crops will stand some heat, they are normally considered cool-weather crops. Plant them in late Winter or early Spring for a spring crop or in the late Summer for a Fall or Winter crop. The seeds of Turnip 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 1/2 in. 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.
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.
Turnips 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 production is 6.0 to 6.5. Apply lime 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 after other cole crops.
A soil test is always the best method for determining the fertilization needs of a crop. If a soil test has not been taken, fertilize Turnips and Rutabagas with 3 lbs. of 5-10-10 fertilizer per 100 sq. ft. Add additional nitrogen when the young plants begin to put on "true leaves," or after a heavy rainfall. Apply calcium nitrate at 2 lbs. per 100 ft. of row, or 33-0-0 at 1 lb. per 100 ft. 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 in. away from the seed row.