How to Grow Turnips

Roots, greens or both

Turnips are grown for two crops, the swollen root and the leafy tops, and varieties lean one way or the other. A variety bred for roots will also give you greens, but a greens variety may never make a good root. Clemson notes that some varieties are grown only for their leaves and never form a swollen root. Pick your variety by what you plan to eat:

• Roots and greens: Purple Top White Globe and Shogoin (Clemson, South Carolina). Maryland Extension also names Purple Top White Globe and Hakurei as dual-purpose in the mid-Atlantic.
• Roots: Royal Crown, White Lady and Hakurei in South Carolina (Clemson). Just Right, Royal Crown, Tokyo Cross and White Lady in Texas (Texas A&M). Purple Top White Globe, the yellow-fleshed Golden Ball and Just Right in Wisconsin (UW Extension).
• Greens: Alamo and Topper (Clemson). Alamo, All Top, Seven Top, Shogoin and Topper (Texas A&M). Seven Top and Shogoin in Florida (UF/IFAS).

When to sow

Turnips are a cool-season crop that loses quality fast in heat, so most of the work is timing.

In spring, sow as soon as the soil can be worked. Texas A&M says turnip seed will sprout once the soil is 40°F, and Colorado State lists turnips among the hardy crops that can go in 2 to 4 weeks before the average last frost. Warmer soil speeds things up a lot: a University of California table shows emergence taking about 5 days at 50°F and about 2 days at 68°F. Spring turnips need to be pulled before summer, because they lose quality and go to seed quickly once days turn long and hot.

Fall is usually the better crop. Texas A&M starts fall sowings 8 to 10 weeks before the first expected frost, and Illinois Extension says very hardy crops like turnips need at least 8 weeks. Wisconsin Extension advises sowing as late as you can while still letting roots mature before a hard freeze, since cool weather produces the best roots. The dates for your zone above show both windows.

In mild-winter areas, sow from late summer through winter. North Florida also gets a late-winter sowing, and the Lower Rio Grande Valley and Phoenix-area calendars run turnips through fall and winter.

Soil and sowing

A smooth, round turnip needs loose soil. Heavy clay makes roots rough and misshapen, so Texas A&M recommends loosening the soil 10 to 12 inches deep and working in compost. Clemson targets a pH of 6.0 to 6.5 and advises adding any lime at least 3 months before planting. Do not plant where cabbage-family crops have grown in the past 3 years.

Sow seed about ½ inch deep, in rows 12 to 18 inches apart. Seed can also be broadcast across a wide row. Keep the surface moist until seedlings are up: seedlings are tender, and a crusted surface leads to a patchy stand. In late summer, a thin cover of compost or potting soil over the row helps.

Thin early, because crowded turnips cannot swell. Recommended final spacing ranges from 2 to 3 inches (Clemson) and 3 to 4 inches (Texas A&M) to 4 inches (Maryland). Texas A&M’s Rio Grande Valley guide thins to 5 to 7 inches, depending on variety. Eat the thinnings as greens.

Feeding and watering

Texas A&M scatters 2 to 3 pounds of 10-20-10 per 100 square feet before planting, noting that phosphorus is especially important for good roots. When plants are 4 to 5 inches tall, side-dress with about ½ cup of fertilizer per 10 feet of row. Clemson side-dresses 3 to 4 weeks after planting and splits the dose in two on sandy soil. Go easy on nitrogen, because too much produces leaves at the expense of roots.

Water regularly through the seedling stage and while roots swell, keeping the soil moist but not soggy. Do not let the leaves wilt.

Pests and problems

• Flea beetles. They chew small holes in young leaves. Cover the row at sowing.
• Root maggots. Cabbage maggot larvae tunnel into roots and leave brown trails. In Wisconsin the adult flies emerge in early to mid-May and lay eggs on the soil surface within 1 to 3 inches of the plants, so spring sowings are most exposed. Use row covers and rotate.
• Aphids and cabbage loopers. Check the undersides of leaves and treat or remove them.
• Pithy, strong-flavored roots. These were left in the ground into hot weather. Harvest on time.
• Rough, misshapen roots. Heavy clay soil is the cause. Loosen it deeply and add organic matter before the next sowing.

Harvest and storage

Most varieties give greens in about 40 days and roots in 50 to 60. Cut greens when the leaves are 4 to 6 inches long, taking the large outer leaves and leaving the center to regrow. Roots are ready at 2 to 3 inches across; Clemson aims for tennis-ball size, about 2½ to 2¾ inches. UF/IFAS notes that 2-inch roots are milder. Wisconsin Extension adds that small, smooth baby turnips can be pulled about 30 days after sowing, but roots are sweeter at 60 to 70 days. Leave them much longer and they turn tough and stringy.

Cut off the tops for storage. Roots keep several weeks in a cool, humid spot or a bag in the refrigerator, and Wisconsin Extension says mature, topped turnips can keep up to 6 months in cold storage. Greens last only a few days in a closed bag in the refrigerator.

Extension services disagree on leaving roots in the ground. Maryland Extension says turnips can be heavily mulched and dug through the winter as needed in the mid-Atlantic. Clemson advises against leaving roots in the ground through hot weather or hard freezes.