When to Plant Turnips

Spring: as soon as the soil can be worked

Turnips are sown directly in the garden, not started indoors, and spring sowing can begin very early. Texas A&M says to plant as soon as the soil can be worked, and that seed will sprout once the soil reaches 40°F. Colorado State puts turnips among the hardy vegetables that can go in 2 to 4 weeks before the average last frost, as soon as the soil has dried enough to work. Together these give a window of roughly 2 to 6 weeks before the last frost, which is what the dates for your zone above show.

Soil temperature decides how fast you get a stand. A University of California emergence table shows turnip seedlings taking about 5 days at 50°F, 3 days at 59°F and 2 days at 68°F. Colorado State suggests checking with a soil thermometer at 8 a.m., 4 inches deep.

Do not push spring sowing too late. Spring turnips need to be harvested before summer, because they lose quality and go to seed quickly once days turn long and hot. Roots left into the heat become pithy and strong-flavored. In Wisconsin, Extension’s usual spring sowing falls in mid to late April, later in the northern part of the state.

There is one spring-specific risk. In Wisconsin, cabbage root maggot flies emerge in early to mid-May and lay eggs beside the plants, so cover early spring sowings with row cover.

Fall: the better crop

Maryland Extension rates fall as the preferable season for turnips, because frost raises the sugar content and flavor of the leaves. Wisconsin Extension adds that cool nights help root crops store carbohydrates in the root. Extension timing for fall sowing:

• Texas A&M: start sowing 8 to 10 weeks before the first expected frost.
• Illinois Extension: sow very hardy crops, including turnips, at least 8 weeks before the average first frost.
• Purdue: plan around about 50 days from sowing to harvest when setting the last feasible planting date.
• Wisconsin Extension: sow as late as possible while still allowing roots to mature before a hard freeze.

Late-summer soil is hot and dry, and turnip seedlings are tender. Keep the seed row moist with light, frequent watering until seedlings emerge, and cover the row with a thin layer of compost, vermiculite or potting soil to stop a crust from forming.

Turnips take frost and light freezes, but plan to finish the harvest before the ground freezes hard. Extension services differ on how far to push it. Clemson advises against leaving roots in the ground through hard freezes, while Maryland Extension says turnip roots can be heavily mulched and dug as needed through winter in the mid-Atlantic.

Mild-winter regions

Where frost is rare, turnips are a fall and winter crop. Hot weather, not cold, is what makes them pithy and harsh.

• Florida: North Florida has two windows, late winter into spring and early fall. Central and South Florida sow from early fall through winter (UF/IFAS).
• Phoenix low desert: the Maricopa County calendar sows turnips from late summer through winter.
• Lower Rio Grande Valley, Texas: Texas A&M’s Cameron County guide sows turnips from fall into early winter.

Sowing for greens versus roots

Greens are ready in about 40 days and roots in 50 to 60, so a fall sowing aimed at greens can go in a little later than one aimed at roots. Wisconsin Extension notes that small baby turnips can be pulled about 30 days after sowing, but full-flavored roots are sweeter at 60 to 70 days. If you want big roots, give them the full time before the first hard freeze.