Turnips are a versatile cool-season crop, offering both nutrient-dense greens and a globe-shaped root. Growing this vegetable in Missouri requires precise timing to align the crop’s growth cycle with the state’s variable temperature shifts. Planting at the wrong time risks developing a tough, woody root or premature bolting (going to seed before the root matures). Understanding the correct seasonal windows is the initial step toward a successful harvest.
Optimal Planting Windows in Missouri
Missouri allows for two distinct turnip crops: a short spring window and a more substantial fall period, which is widely considered the superior growing season. For a spring harvest, sow seeds directly two to four weeks before the last expected frost date in your region. This early planting allows plants to establish and mature before intense summer heat arrives (generally when temperatures consistently exceed 80°F).
Rising soil temperatures stress the plant, causing premature bolting and shifting energy from root development to seed production. This results in tough, small, and bitter roots. Northern Missouri gardeners, where the last frost date is later, must select quick-maturing varieties to ensure harvest before high summer temperatures.
The fall planting window is preferred because cool weather enhances the root’s flavor. Turnips planted in late summer or early fall develop a sweeter, milder flavor as they mature. Target planting time is 8 to 10 weeks before the first expected hard frost date.
A light frost (temperatures just below freezing) triggers the plant to convert starches into simple sugars, concentrating them in the root. This process improves the taste and texture of the turnip. Southern Missouri gardeners, with a later first-frost date, can extend their planting window deeper into the late summer.
Soil Preparation and Planting Technique
Successful turnip cultivation requires properly prepared soil, as roots need a loose, obstruction-free environment to develop symmetrically. Work the planting bed 12 to 15 inches deep, ensuring the soil is well-drained to prevent waterlogging. Clay soils benefit from incorporating aged manure or compost to improve texture and drainage.
Turnips do not transplant well because disturbing the taproot hinders proper root formation, so seeds must be sown directly. Plant seeds shallowly, typically one-half inch deep, and lightly cover them with soil. Initial spacing can be close, about one inch apart, to ensure good germination rates.
The soil should be nearly neutral to slightly acidic; avoid using fresh manure or nitrogen-heavy fertilizers. Too much nitrogen encourages excessive growth of greens at the expense of the root, resulting in small, underdeveloped roots. Clear the planting area of rocks or large clumps, as physical obstructions can cause roots to fork or become malformed.
Essential Care and Harvesting
Once seedlings emerge, thinning is necessary to allow remaining plants space for proper root development. For root crops, thin seedlings to space remaining plants four to six inches apart. If the primary goal is harvesting greens, a closer spacing of two to four inches is acceptable, as root size is less critical.
Turnips require consistent moisture throughout their growth cycle to prevent roots from becoming tough, woody, or bitter. Providing about one inch of water per week is a general guideline, adjusting during drought or excessive heat. Applying organic mulch helps maintain soil moisture and keeps soil temperature cool, reducing plant stress.
Greens can be harvested before roots mature by carefully cutting only the outer leaves, leaving the inner growth point intact. For root harvest, turnips are ready when they reach two to three inches in diameter, offering the best tenderness and flavor. Harvest the entire crop before the ground freezes solid; flavor is often enhanced by waiting until after one or two light frosts.