Fall is the prime season for planting turnips in Tennessee, with most gardeners getting the best results from seeds sown between mid-August and mid-September. A secondary window opens in early spring, roughly late February through March, but fall plantings generally produce sweeter roots and healthier greens because turnips thrive in cooling weather and actually improve in flavor after a light frost. The exact dates shift depending on whether you’re in the mountains of East Tennessee, the rolling hills of the middle of the state, or the warmer lowlands out west, and understanding why those windows matter can make the difference between a bumper harvest and a bed of bitter, woody roots.
Why Fall Planting Works Best
Turnips are a cool-season crop. They grow fastest and taste best when daytime temperatures hover between about 50°F and 65°F, conditions that Tennessee sees reliably from late September through November. By sowing seed in mid-August to mid-September, you give the plants a few weeks of warm soil to germinate quickly and then let them size up as temperatures drop. The cooling nights sweeten the roots by encouraging the plant to convert starches into sugars, a natural antifreeze response that gardeners in Tennessee have relied on for generations.
Fall plantings also dodge two problems that plague spring crops. First, pest pressure from flea beetles and aphids tends to taper off in autumn. Second, and more important, turnips that mature into rising heat often bolt, sending up a flower stalk instead of filling out a plump root. Research on swede turnips found that sustained exposure to cool temperatures around 53°F for 30 to 50 days triggered the onset of bolting, while plants kept at consistently high temperatures remained vegetative. In a fall garden this is rarely an issue because you harvest before deep winter sets in, but in spring the danger runs the opposite direction: a late cold snap can vernalize young plants, and then lengthening days push them to flower just as you want them to be bulking up.
The Spring Window
Spring planting is still worthwhile if you time it carefully. The goal is to get seed in the ground early enough that the roots mature before summer heat arrives. In most of Tennessee, that means sowing from late February through the middle of March. Turnips can handle light frost, and seeds germinate at soil temperatures as low as about 40°F, though they sprout much faster once the soil reaches the mid-50s. Research on the Brassica rapa group, which includes garden turnips, estimated a base germination temperature of roughly 37 to 39°F, with an optimum near 88°F for the germination process itself.
1European Journal of Agronomy. A comparison of cardinal temperatures estimated by linear and nonlinear models for germination and bulb growth of forage brassicasThat optimum sounds counterintuitively warm for a cool-season crop, but germination speed and growing-season preference are different things. A turnip seed will sprout fastest in warm soil, yet the plant that emerges produces its best-quality root under cool air temperatures. In practical terms, spring-planted turnips in Tennessee should be ready to pull within 45 to 60 days, ideally before daily highs start consistently clearing 80°F. If you are growing turnips mainly for their greens rather than the root, you can get away with planting a week or two later since greens are harvested younger.
Timing by Region
Tennessee stretches more than 400 miles from the Appalachian ridges in the east to the Mississippi River floodplain in the west, and that geography creates real differences in planting dates.
- East Tennessee: Higher elevations around Knoxville and the Smoky Mountain foothills bring earlier fall frosts, often by mid-October. Aim for fall sowing between early August and early September so roots have time to size up. Spring planting can start around mid-March once soil thaws, though mountain valleys with late frost pockets may push that into late March.
- Middle Tennessee: Nashville and the surrounding Cumberland Plateau generally see first frost around late October to early November. Fall sowing from mid-August through mid-September works well here. Spring planting from late February to mid-March gives a comfortable runway before summer heat.
- West Tennessee: The Memphis area and the lowlands along the Tennessee River are the warmest part of the state. First frost often holds off until early November. You can push fall sowing into late September if needed, though earlier is still better. Spring planting can begin as early as mid-February in mild years, but watch for wet soil that stays cold and delays germination.
These are guidelines, not hard rules. A warm autumn can stretch the fall window, and an unseasonable March cold snap can stall spring plantings regardless of where you are. Checking actual soil temperature with a cheap probe thermometer is more reliable than going by the calendar alone.
What Happens When You Plant Too Late or Too Early
Planting turnips outside their sweet spot in Tennessee leads to predictable problems. A fall sowing in late October, for example, often means the seeds germinate fine but the plants run out of warm days before the roots reach harvest size. You end up with decent greens but marble-sized roots. A spring sowing in late April, on the other hand, sends the plants straight into the heat of May and June. The roots turn tough, woody, and bitter as the plant rushes to reproduce.
That bitterness comes from glucosinolates, the same sulfur-containing compounds that give all brassicas their sharpness. Turnips under heat stress ramp up glucosinolate production, and without the cool temperatures that prompt sugar accumulation, the balance tips toward an unpleasant bite. This is why veteran Tennessee gardeners insist that turnips pulled after the first fall frost taste noticeably sweeter than anything harvested in warm weather. The frost itself does not add sugar, but weeks of cooling weather before it does.
Bolting is the other major timing risk. The research on swede turnips showed that extended exposure to temperatures near 53°F triggered the reproductive switch, with internode elongation and stunted root development following about 71 days after seeding.2Canadian Journal of Research. THE CAUSE OF BOLTING IN SWEDE TURNIPS (BRASSICA NAPUS VAR. NAPOBRASSICA (L.) PETERM.) Garden turnips are somewhat less sensitive than swedes, but the principle holds: a prolonged cool period followed by warming and lengthening days can flip the plant from root-building mode to flower mode. In Tennessee’s spring, this pattern is exactly what March and April deliver, which is why getting spring turnips in the ground early and harvesting promptly matters so much.
Choosing a Variety for Tennessee Conditions
Variety selection interacts with timing. Fast-maturing types like ‘Purple Top White Globe’ and ‘Tokyo Cross’ reach harvest size in 45 to 55 days, making them forgiving if your planting window is tight. They are the standard recommendation for both spring and fall gardens across the state. ‘Hakurei,’ a Japanese salad turnip, matures even faster and produces tender, mild roots best eaten raw, but its thin skin makes it less tolerant of hard frost, so fall plantings should be timed for harvest before temperatures drop below the mid-20s.
‘Seven Top’ is a greens-only variety widely grown in the South, including Tennessee. Since you are not waiting for a root to size up, it can be planted later in fall than root varieties and still produce well. Many Tennessee gardeners scatter ‘Seven Top’ seed in September and begin cutting greens within a month.
For anyone interested in storage turnips, ‘Gilfeather’ and ‘Golden Ball’ offer denser roots that hold up in a root cellar for weeks. These types generally need a few extra days to mature, so plan on planting them at the earlier end of the fall window, around early to mid-August, especially in East Tennessee.
Succession Planting for a Longer Harvest
One of the simplest ways to extend your turnip season is to sow seed in two or three rounds, spaced about two weeks apart, rather than putting everything in the ground at once. A first fall sowing around August 10, a second around August 25, and a third around September 10 can stagger harvests from late September through Thanksgiving in Middle Tennessee. Each round produces roots at a slightly different stage, so you are never swamped with turnips all at once and never without them for long.
Succession planting also hedges against weather. If a September heat wave damages your earliest sowing, the later rounds often recover in cooler conditions. In spring, two rounds spaced two weeks apart in late February and mid-March give you a similar cushion, though the spring window is tighter because rising heat eventually shuts production down regardless.
Growing for Greens Versus Roots
If you are growing turnips mainly for the greens, your timing can be a bit more relaxed. Turnip greens are ready to cut in as little as 30 days from sowing, which means even a late September planting in West Tennessee can yield several harvests of greens before frost kills the tops. Young turnip greens are milder and more tender than mature leaves, so frequent cutting of outer leaves while the center keeps growing is the standard approach.
If you want both greens and roots, avoid harvesting too many leaves from any single plant. The root depends on those leaves to photosynthesize and feed its growth. A good compromise is to take no more than a third of the foliage at a time and let the plant recover before cutting again. Fall plantings handle this dual-harvest approach well because the longer growing window gives the plant time to regenerate leaves while still sizing up the root.
Forage Turnips and Pasture Planting
Tennessee’s livestock producers, particularly cattle and sheep farmers, plant turnips for a different reason entirely: as a high-protein fall and winter forage crop. Forage turnip varieties like ‘Purple Top’ and ‘Tyfon’ (a turnip-rapeseed hybrid) are broadcast-seeded into prepared fields or overseeded into thinning summer pastures. The timing for forage plantings is broadly similar to garden plantings, with late July through August being the target window.
Research on forage turnips showed that planting date strongly influenced the proportion of tops to roots. June and July plantings produced plants that were roughly half leaf and half root by late autumn, while August plantings were much more top-heavy, with leaves making up 70 to 90 percent of the total plant mass.3Crop Science. Planting Date and Seeding Rate Effects on Morphological Development and Yield of Turnip That matters because livestock eat both parts, but the root provides more energy per pound. A Tennessee cattle farmer who wants maximum root tonnage for winter grazing should plant on the early side of the window, ideally in July, while someone looking mostly for leafy fall forage can sow in August and still get good production.
Total forage yields in that research sometimes exceeded 10 tons per hectare, making turnips competitive with other cool-season annuals like ryegrass or small grains for fall and early winter grazing.3Crop Science. Planting Date and Seeding Rate Effects on Morphological Development and Yield of Turnip Turnips also break up compacted soil with their taproots, which gives pastures a secondary benefit the following spring.
Soil Preparation and Practical Tips
Turnips are not fussy about soil, but they do best in loose, well-drained ground with a pH between about 6.0 and 6.8, which conveniently matches much of Tennessee’s naturally slightly acidic soil after a standard lime application. If your soil is heavy clay, as it often is in the Nashville Basin, working in compost or aged leaves before planting improves drainage and makes it easier for the root to expand evenly. Rocky or compacted soil produces misshapen roots with forked taproots.
Sow seed about a quarter to a half inch deep. Turnip seed is small, and planting too deep is the most common beginner mistake. In fall, the soil surface can dry out quickly in August heat, so a light daily watering until seedlings emerge is helpful. Once the plants are up, thin them to about four to six inches apart if you want good-sized roots. Skipping the thinning step is the second most common mistake. Crowded turnips produce lots of greens and almost no root.
Turnips need consistent moisture but not soggy conditions. About an inch of water per week, whether from rain or irrigation, keeps them growing steadily. Drought stress, even for a short period, can cause the roots to crack or develop a pithy, hollow center when moisture returns. Mulching between rows with straw helps hold soil moisture and keeps roots cooler during September’s lingering warmth.
Common Pests and Diseases in Tennessee
Flea beetles are the biggest pest threat to turnips across the state. These tiny jumping beetles chew small holes in the leaves of young seedlings, and a heavy infestation can kill plants before they establish. Fall plantings generally face lighter flea beetle pressure than spring plantings, which is another mark in fall’s favor. Floating row cover placed over the bed immediately after sowing is the simplest organic defense. If you see damage, spinosad-based sprays are effective and approved for organic use.
Aphids sometimes colonize the undersides of turnip leaves in warm weather, causing curling and yellowing. A strong blast of water from a hose knocks most of them off, and cooler fall temperatures usually solve the problem without intervention. Cabbage loopers and imported cabbageworms also feed on turnip greens but rarely cause enough damage to reduce root yield significantly. Hand-picking or Bt (Bacillus thuringiensis) spray handles them if they become heavy.
Disease-wise, downy mildew and white rust are the most common fungal issues on turnips in Tennessee’s humid conditions. Both thrive in wet foliage, so watering at the base of the plant rather than overhead, and spacing plants for good air circulation, reduces risk. Crop rotation is important too: avoid planting turnips or any other brassica in the same spot for at least two years to break disease and pest cycles in the soil.
Storing the Harvest
Fall-harvested turnips store far better than spring-harvested ones because the roots go into storage already cold-conditioned. After pulling, twist off the greens about an inch above the root to prevent the leaves from drawing moisture out during storage. Do not wash the roots until you are ready to use them. Stored in a perforated plastic bag in the refrigerator, turnips keep for two to three months. In a traditional root cellar held around 32 to 40°F with high humidity, they can last even longer.
Turnip greens, by contrast, are perishable. Wrap them in a damp towel inside a bag and use within four or five days. Blanching and freezing is the standard preservation method for greens in Tennessee, and a single fall planting can fill a freezer with enough greens for winter meals. Many gardeners harvest greens progressively through October and November, blanch and freeze each batch, and then pull the roots after a hard frost for fresh eating or cellar storage.