How to grow turnips

Turnips get less attention than they deserve. They are faster than beets, hardier than most brassicas, and doubly productive: the greens are edible from thinning onward, and the root comes in well before summer. Like all root crops, they have a few non-negotiable requirements, loose soil, consistent moisture, and harvesting on time, but they are genuinely easy for beginners who understand the cool-season rhythm.

When to plant turnips

Turnips are a cool-season brassica. They tolerate light frost (roots can handle temperatures down to about 26 degrees F with hardening) and actually improve in flavor after light frost exposure in fall. Heat is the problem: roots that mature in warm weather become woody and bitter.

Spring: Direct-sow 4 to 6 weeks before your average last spring frost date. In most regions, this means getting seeds in the ground while nights are still cold. Germination proceeds fine down to about 40 degrees F soil temperature.

Fall: Sow 6 to 8 weeks before your average first fall frost. Fall turnips are often the best-tasting, as cool and gently frosty conditions sweeten the roots. This is the season that extension specialists from University of Georgia, Virginia Cooperative Extension, and others consistently favor for turnip flavor.

Site and soil preparation

Turnips need loose, well-drained soil free of rocks and large clumps to form clean, round roots. Heavy clay causes deformities; shallow or compacted soil produces stunted roots.

Full sun. At least 6 hours for root development, though turnips tolerate more shade than most root crops.

Loose soil to 10 to 12 inches. Work the bed deeply with a fork before sowing. Remove stones. Add compost to improve drainage in clay and water retention in sandy soils.

pH 6.0 to 7.5. Turnips are somewhat pH-tolerant compared to other brassicas, but soils below 6.0 increase susceptibility to clubroot.

Go easy on nitrogen. As with all root crops, excess nitrogen produces lush greens at the expense of the root. Compost is the right amendment; avoid fresh manure or high-nitrogen fertilizers.

A raised bed with amended, deep fill is excellent for turnips. The how to build healthy garden soil guide covers amending in-ground beds before planting root crops.

Planting and thinning

Direct sow turnip seeds 0.5 inches deep, spacing seeds about 1 inch apart. Rows should be 12 to 18 inches apart; in raised beds, you can reduce row spacing to 9 inches.

Germination typically takes 3 to 7 days in ideal conditions (60 to 65 degrees F soil). Once seedlings have one true leaf, begin thinning.

Watering and feeding

Consistent moisture is important for smooth, uniform roots. Dry spells cause bitterness, pithiness, and cracking. Aim for 1 inch of water per week from rain or irrigation.

Overhead watering can promote foliar disease in brassicas. A soaker hose keeps moisture at the root zone without wetting foliage, which is worth it especially in fall when cool, moist air already encourages disease pressure.

Turnips in compost-amended soil rarely need supplemental fertilizer. If growth stalls and leaves look pale yellow-green, a light application of a balanced fertilizer (not high in nitrogen) can help. Use the Jobes Organics Vegetable Fertilizer at half the labeled rate if supplemental feeding is needed.

Common problems

Turnips share pest pressure with other brassicas, since they belong to the same family (Brassicaceae).

Flea beetles are the most common early-season pest: tiny beetles chewing small round holes in seedling leaves. Young transplants are most vulnerable; established plants tolerate some damage. Row cover at sowing prevents them. See flea beetles.

Cabbage maggots tunnel into roots, causing wilting, rot, and deformed roots. They are more damaging than flea beetles and harder to control after the fact. Row cover prevents the egg-laying adult fly from accessing the soil near plant bases. Rotate turnips away from brassica crops for 2 to 3 years to reduce resident populations. Full details: cabbage maggots.

Cabbage worms (both imported cabbage worm and cabbage loopers) feed on turnip foliage. They can cause significant defoliation on young plants. Hand-picking and Bt (Bacillus thuringiensis) applied at the first sign of damage are effective controls.

Clubroot is a soilborne disease causing swollen, distorted roots and wilting. It builds up when brassicas are grown repeatedly in the same soil. Maintaining soil pH above 7.0 inhibits the pathogen. Do not plant turnips in the same ground more than once every 3 to 4 years. See clubroot.

Aphids cluster on the undersides of leaves, particularly in cool weather. Beneficial insects often keep populations in check. Heavy infestations distort growth, especially on young plants. See aphids.

Harvesting turnips

Turnips are ready to harvest when roots are 2 to 3 inches in diameter. This is typically 35 to 60 days after sowing depending on variety (small salad types mature faster; larger storage types take longer).

Pull roots before heat arrives in spring, or after light frosts in fall but before hard repeated freezes damage them in the ground.

Turnip greens are best harvested young (the outer leaves on plants before the root has sized up, or all the greens from thinnings). Older greens from mature plants are edible but more pungent.

When is the best time to plant turnips?

Fall is generally the best season for turnip flavor. Sow 6 to 8 weeks before your first fall frost. Roots that mature in cool, slightly frosty conditions are sweeter and milder than spring-grown roots. Use the frost dates and planting calendar to find your specific sow date.

Why are my turnips woody and bitter?

Roots left in the ground too long or that matured during hot weather become tough and bitter. Harvest at 2 to 3 inches in diameter before heat arrives. Fall turnips that overwinter without harvest also degrade. When timing is right, turnips are mild and slightly sweet.

Can I eat turnip greens?

Yes. Turnip greens are edible at every stage, from the seedling thinnings (mild and tender) to the mature leaves on rooted plants (more assertive in flavor). Use thinnings raw in salads. Larger greens are typically cooked. They are nutritious and a traditional staple in Southern US cooking.

How far apart should I thin turnips?

Final spacing for root production is 4 inches apart. For greens-only production, 2 to 3 inches is fine. Thin in two passes: first to 2 inches when seedlings are a few inches tall, then to the final spacing. Crowded turnips produce undersized roots.

How do I prevent clubroot in my turnips?

Clubroot is a soilborne pathogen that builds up in brassica beds over time. The most effective prevention is crop rotation: do not plant any brassica family crop (turnips, cabbage, broccoli, kale, radishes) in the same bed more than once every 3 to 4 years. Also maintain soil pH above 6.8, since clubroot is less active in near-neutral to slightly alkaline soil. See clubroot for more.

The bottom line

Turnips are one of the most productive cool-season crops per square foot: you get edible greens from thinning onward and a harvestable root in 35 to 60 days. Time the sow off your actual frost dates, thin to 4 inches, harvest before heat or over-maturity sets in, and you will get mild, sweet roots that bear no resemblance to the bitter, oversized turnips that gave this crop an undeserved bad reputation.