When to Plant Turnips in Colorado
Published: April 24, 2026
Colorado gardeners in Zone 6a have a 31-week growing season for turnip (March 30 to November 1). Colorado's spring and fall windows both work well for turnip — some gardeners plant both successions for a long harvest. This guide gives exact dates for Colorado based on your local frost calendar.
Turnip Planting Dates for Colorado
| Start seeds indoors | Year-round |
| Last frost (average) | March 30 |
| Direct sow outdoors | March 9–19 |
| Expect first harvest | April 13 – May 8 |
| Fall crop start | September 6–16 |
| Fall harvest | October 11 |
| First fall frost (average) | November 1 |
Dates above assume Zone 6a, the most common zone in Colorado. Gardeners in cooler Denver (Zone 6a) plant 1–2 weeks later; warmer Colorado Springs (Zone 6b) can plant 1–2 weeks earlier.
⚠ Direct sow turnips 2–4 weeks before last frost for spring crop. Best planted in late summer (6–8 weeks before first fall frost) for fall harvest — frost sweetens the roots. Fast-growing: some varieties ready in just 35 days.
Growing Turnips in Colorado's Climate
Colorado's moderate Zone 6a climate is well-suited to turnip with minimal special accommodation. The standard transplant calendar works as written, and harvest windows line up with what seed packets recommend without adjustment.
Succession planting extends your turnip harvest significantly in Colorado. A second planting 3 to 4 weeks after the first gives you a backup in case of pest pressure and extends the total harvest window into early fall.
Common turnip pests to watch for in Colorado include Flea Beetle and Aphid. The first line of defense is companion planting: Pea and Mint planted nearby discourage several of these pests by confusing host-plant identification or repelling adults before they can lay eggs. Weekly garden walks in the early morning catch problems when they're still manageable.
Turnip Garden Calendar for Colorado
| Month | Task | Notes |
|---|---|---|
| January | — | Dormant season |
| February | — | Dormant season |
| March | Direct sow seeds | Sow seeds 1/4–1/2 inch deep, 4 inches apart |
| April | First harvest window opens | Turnip begins producing 35–60 days after transplant |
| May ← | Watch for bolting | Harvest promptly; spring heat arrives quickly |
| June | — | Dormant season |
| July | — | Dormant season |
| August | — | Dormant season |
| September | Fall crop planting | Transplant or direct sow for fall harvest before frost |
| October | — | Dormant season |
| November | First frost approaches | Harvest remaining turnip; cover plants on frost nights |
| December | — | Dormant season |
Turnip Growing Tips for Colorado Gardeners
- •Thin seedlings to 4-inch spacing when plants are 3 inches tall — crowded turnips produce small woody roots.
- •Both roots AND greens are edible — harvest baby turnip greens 4 weeks after sowing, roots 5–9 weeks.
- •Colorado's moderate climate supports succession planting — sow new transplants or seeds every 3 weeks during spring to extend the harvest window into fall.
- •Fall turnips are sweetest — plant 8 weeks before first frost and let cold weather convert starches to sugars.
Companion Planting for Turnips in Colorado
In Colorado's moderate climate, planting turnip with Pea and Mint helps deter pests and improve soil. Avoid planting near Potato and Radish, which inhibit turnip growth through root chemistry or shared pest pressure. See the full turnip companion planting guide for the complete list.
Turnips Planting Dates by City in Colorado
Top cities in Colorado — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant turnip in Colorado?
In Colorado (Zone 6a), start turnip seeds indoors around Year-round and transplant outdoors around null — 0 weeks after the state's average last frost of March 30.
What is the last frost date in Colorado?
Colorado's average last frost date is March 30 in the state's most common Zone 6a. Frost dates vary by city — higher elevations and northern counties run 1 to 3 weeks later than the state average. See the city list below for city-level frost dates.
Can I grow turnip year-round in Colorado?
turnip is a cool-season crop in Colorado, with spring and fall windows. Summer heat bolts the plants before they can produce a harvestable crop. Succession planting every 2–3 weeks stretches the harvest window.
What turnip varieties grow best in Colorado?
For Colorado's Zone 6a, consult a local nursery or extension office for turnips variety recommendations.
When do I start turnip seeds indoors in Colorado?
Turnip does not need indoor starting in Colorado — direct sow around March 9–19 once soil reaches 40°F. Indoor starting is not recommended for this crop because turnip transplants poorly.