Turnips are a versatile cool-season crop, valued for their tender, leafy greens and crisp, bulbous roots. Successful planting in Kentucky requires timing sowing to avoid harsh summer heat, which causes roots to become woody and bitter. The state’s climate provides two distinct, productive windows for cultivation. Knowing local frost dates and soil temperature is the most reliable way to schedule planting for a rewarding harvest.
Optimal Spring Planting Window
The goal for spring planting is to harvest greens before summer heat arrives. Turnips are hardy and can be planted as soon as the soil is workable in early spring, typically four to six weeks before the last expected frost date. For most of Kentucky, this window opens around mid-March and continues through early April.
Planting should occur when the soil temperature consistently reaches at least 40°F, though a range of 60°F to 85°F is optimal for quick germination. This early timing allows the plants to establish themselves in the cool, moist conditions they prefer. Spring-sown turnips are best harvested for their greens, which mature quickly, often within 30 to 50 days of sowing.
Attempting to grow large roots in the spring is risky. The long, hot days of late spring often trigger the plants to “bolt,” or flower and go to seed, which halts root development and degrades the quality of the greens. Focus on a quick harvest of young, tender leaves before the average last frost date, which generally falls between April 1st and May 15th across the state.
Fall Planting for Root Development
Fall is the preferred season for cultivating mature turnip roots, as decreasing temperatures enhance their natural sweetness. The ideal time to sow seeds for a root harvest is late summer, allowing the roots to develop during the cooler months. Gardeners should aim to plant approximately 60 to 75 days before the first expected hard frost.
This timing generally places fall planting between late July and mid-August in Kentucky, with some western regions planting as late as September. Planting during this period ensures that the turnip bulbs bulk up during the mild autumn weather. Cooler soil temperatures, especially those below 50°F, cause the plant to convert starches into sugars, resulting in the sweeter, milder flavor sought in fall turnips.
The mild Kentucky winter allows for an extended harvest, often continuing well past the first light frost, which typically occurs between October 1st and November 10th. Light frost improves the taste of the roots, but they must be harvested before a deep, sustained freeze. The fall-sown crop yields both roots and greens, benefiting from the cool weather.
Selecting Turnip Types for Kentucky Gardens
Choosing the correct variety significantly impacts success, especially given Kentucky’s humid conditions. Varieties are often categorized by their primary use, either for greens or for roots.
The ‘Purple Top White Globe’ is a standard and reliable selection, favored for its smooth, globe-shaped roots and consistent performance in the region. For growers prioritizing the leafy harvest, the ‘Seven Top’ turnip is an excellent choice, as it is specifically bred for prolific leaf production. Another good option for a dual-purpose harvest is the ‘White Egg’ turnip, which produces mild, white-fleshed roots.
Selecting varieties with disease resistance can help mitigate common problems like Alternaria leaf spot or white mold, which thrive in humid environments.
Initial Care and Thinning After Planting
Turnip seeds should be sown directly into the prepared garden bed at a depth of about a half-inch. Consistent moisture is necessary during the germination phase to ensure a good stand. Watering about one inch per week is a good goal, paying special attention during root enlargement to prevent the roots from becoming tough or pithy.
The most important task after germination is thinning, which must be performed once the seedlings develop their first true leaves and are about four inches high. Crowding results in small, malformed, and woody roots, so plants must be spaced four to six inches apart.
Thinning is accomplished by snipping the weaker seedlings at the soil line to avoid disturbing the roots of the remaining plants. Early monitoring for pests like flea beetles is also advisable, as they can quickly damage young leaves.