When to Plant Cauliflower in Washington, DC
Published: April 24, 2026
Cauliflower Planting Dates for Washington, DC
| Start seeds indoors | February 15–22 |
| Last frost (average) | March 22 |
| Transplant outdoors | March 1–11 |
| Minimum soil temperature | 45°F |
| Expect first harvest | April 25 – June 9 |
| Fall crop planting | September 1–11 |
| Fall crop harvest | October 26 |
| First fall frost (average) | November 10 |
⚠ Start cauliflower indoors 4–6 weeks before last frost. Transplant 2–4 weeks before last frost. Needs consistent moisture and cool temps — bolts in heat above 75°F.
Best Cauliflower Varieties for Washington, DC
Consult a Washington-area nursery or your state extension office for cauliflower varieties proven in Zone 6b.
Growing Cauliflower in Washington
Washington sits in Zone 6b, with an average last frost of March 22 and first fall frost around November 10 — giving a 233-day frost-free growing season. Cool-season crops like cauliflower benefit from Washington's cooler spring and fall windows, when temperatures stay in the 55–75°F sweet spot that produces the best flavor and least bolting.
Washington's moderate climate supports cauliflower on the standard transplant calendar with minimal special accommodation. Succession planting — sowing fresh seeds or setting new transplants every 2–3 weeks through spring — stretches the harvest window and gives you a backup crop if pests hit the first planting.
Washington's mixed soil conditions vary block by block — get a soil test if you have not in three years. Generally, a base of quality compost (2 to 3 inches annually) and consistent watering at 1.5 inches per week serves cauliflower well across most soil types found in Washington.
Cauliflower Calendar for Washington
| Month | Task |
|---|---|
| February | Start seeds indoors under grow lights |
| March | Transplant outdoors into warm soil |
| April | Expect first harvest window to open |
| September | Start fall crop — transplants or direct sow |
| November | First fall frost — harvest remaining, end of outdoor season |
Cauliflower Tips for Washington Gardeners
- •Blanch white varieties by tying outer leaves over the head when it reaches egg-size — prevents yellowing from sun exposure.
- •Keep soil evenly moist — drought stress causes small, bitter 'buttoning' heads instead of full curds.
- •Succession plant cauliflower in Washington every 2–3 weeks through spring to extend the harvest window into summer.
Common Cauliflower Pests in Washington
- •Cabbage Worm — peaks July in Zone 6b (active May–September); green caterpillars on brassicas; apply Bt spray or use row covers.
- •Cabbage Looper — peaks July in Zone 6b (active May–September); loop-walking green caterpillars; Bt spray works well.
- •Aphid — peaks July in Zone 6b (active May–September); monitor closely during peak season and treat early.
Check plants every 2–3 days during peak season — early intervention prevents most infestations from becoming serious.
What to Plant with Cauliflower in Washington
In Washington's moderate climate, Onion and Celery are the most beneficial plants to grow alongside cauliflower. Onion deters carrot fly, aphids, and several root-zone pests through sulfur compounds. Keep cauliflower away from Tomato — it competes for nutrients or shares pest pressure.
Frequently Asked Questions
When should I plant cauliflower in Washington, DC?
In Washington (Zone 6b), start cauliflower seeds indoors around February 15–22 and transplant outdoors around March 1–11. The city's average last frost of March 22 is the anchor date — count 5 weeks back for seed starting and 3 weeks back for transplanting.
What zone is Washington, DC for cauliflower growing?
Washington is USDA Zone 6b. For cauliflower, this means a frost-free growing season of roughly 33 weeks running from March 22 to November 10. Cool-season crops like cauliflower thrive in this zone with both spring and fall planting windows available.
When is cauliflower harvest season in Washington?
Expect the first cauliflower harvest in Washington around April 25, with harvest continuing through June 9. This is based on 55–100 days from transplant or direct sow. A fall crop planted September 1–11 adds a second harvest around October 26.
How long does it take to grow cauliflower in Washington, DC?
From transplant or direct sow to first harvest, cauliflower takes 55–100 days in Washington's climate. Based on a typical planting date of March 1–11, expect your first harvest around April 25. Washington's Zone 6b transition-zone climate produces maturity times right in the middle of the stated range.
What soil does cauliflower need in Washington?
Washington's soil conditions vary block by block. Before planting cauliflower, do a soil test (most state extension offices run them for $15–30). The test reveals pH, key nutrient levels, and organic matter content, so you can amend appropriately rather than guessing. Generally, 2–3 inches of compost annually improves most soils for vegetable production.