When to Plant Turnips in Washington
Published: April 24, 2026
Washington gardeners in Zone 4b have a 21-week frost-free window for turnip (May 7 to October 1). Cool-season crops like turnip do well here because the short, cool summers match the plant's temperature preferences naturally. This guide gives exact dates for Washington based on your local frost calendar.
Turnip Planting Dates for Washington
| Start seeds indoors | Year-round |
| Last frost (average) | May 7 |
| Direct sow outdoors | April 16–26 |
| Expect first harvest | May 21 – June 15 |
| Fall crop start | August 6–16 |
| Fall harvest | September 10 |
| First fall frost (average) | October 1 |
⚠ 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 Washington's Climate
Washington's cold Zone 4b climate is close to ideal for turnip. The cool springs and moderate summers match the plant's natural temperature preferences, producing crisp, sweet, slow-bolting harvests that hot-climate gardeners cannot grow.
The fall turnip crop in Washington is often better than the spring crop. Plants mature as temperatures cool in September and October, concentrating sugars and tightening heads or roots. Light frost can improve flavor; hard frost signals harvest time.
Common turnip pests to watch for in Washington 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 Washington
| Month | Task | Notes |
|---|---|---|
| January | — | Dormant season |
| February | — | Dormant season |
| March | — | Dormant season |
| April | Direct sow seeds | Sow seeds 1/4–1/2 inch deep, 4 inches apart |
| May ← | Watch for bolting | Harvest promptly; spring heat arrives quickly |
| June | — | Dormant season |
| July | — | Dormant season |
| August | Fall crop planting | Transplant or direct sow for fall harvest before frost |
| September | — | Dormant season |
| October | First frost approaches | Harvest remaining turnip; cover plants on frost nights |
| November | — | Dormant season |
| December | — | Dormant season |
Turnip Growing Tips for Washington 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.
- •Washington's short growing season means start seeds indoors under grow lights — don't rely on windowsill light which produces leggy, weak seedlings that struggle outdoors.
- •Cover young transplants with floating row covers for the first 2–3 weeks outside. The 3–5°F of protection reduces frost damage risk and accelerates early growth.
- •Fall turnips are sweetest — plant 8 weeks before first frost and let cold weather convert starches to sugars.
Companion Planting for Turnips in Washington
In Washington's cold 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 Washington
Top cities in Washington — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant turnip in Washington?
In Washington (Zone 4b), start turnip seeds indoors around Year-round and transplant outdoors around null — 0 weeks after the state's average last frost of May 7.
What is the last frost date in Washington?
Washington's average last frost date is May 7 in the state's most common Zone 4b. 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 Washington?
turnip is a cool-season crop in Washington, 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 Washington?
For Washington's Zone 4b, consult a local nursery or extension office for turnips variety recommendations.
When do I start turnip seeds indoors in Washington?
Turnip does not need indoor starting in Washington — direct sow around April 16–26 once soil reaches 40°F. Indoor starting is not recommended for this crop because turnip transplants poorly.