The Early Cultivation of Turnips

Site Preparation

• Turnips require loose, deep soil to form full-size roots. A slightly sandy growing location works well, or you can incorporate a 2- to 4-inch layer of compost into the top 8 inches of soil to help loosen it. The site must drain well so it doesn't become soggy. It also must receive six or more hours of direct sunlight daily. An application of 1 cup of 10-10-10 fertilizer per 50 square feet of garden bed, worked into the top 6 inches of soil before you plant, provides nutrients for the initial turnip growth period.

Planting Process

• Turnip seeds typically are sown directly in the garden bed after the soil temperature warms to at least 40 degrees Fahrenheit in early spring. Fall plants require sowing after the soil temperature drops to 60 to 70 degrees Fahrenheit in early fall. Seeds require planting at a depth of 1/4 inch. Sow seeds about 2 inches apart in rows set 12 inches apart. After the seeds germinate, which can take up to two weeks, thin the seedlings, removing some so that the remaining seedlings are 4 inches apart in a row.

Early Care

• Once-weekly irrigation that supplies 1 to 2 inches of water, or enough to moisten the top 6 inches of soil, provides optimum soil moisture. It's better to water deeply once each week than to provide light watering daily. A 1- to 2-inch deep layer of mulch laid over the soil when the turnip plants are 4 to 6 inches tall helps to retain moisture in the soil. Turnips don't require additional fertilization until the seedlings are about six weeks old. An application of ¼ cup of 21-0-0 nitrogen fertilizer, sprinkled along each 10 feet of row at a 6-inch distance from the plants, provides nutrients for the remainder of the growing season. Water the garden bed after the fertilizer application.

Pests and Problems

• Turnip seedlings may suffer from Alternaria leaf spot, or damping off. Using drip irrigation and avoiding overhead watering minimizes damping off. Aphids, cutworms and other insect pests may infest turnips. Placing a plant collar over each emerging seedling minimizes cutworm damage. Pulling weeds as soon as they emerge helps to prevent insects from invading the garden. Also, a sharp spray of water can rinse off aphids and other soft-bodied insects from turnip plants. Alternatively, spray infested turnip leaves with a ready-to-use insecticidal soap product, completely coating the foliage, at three- to five-day intervals until the pests are gone.