When to Plant Broccoli in Missouri
Published: April 21, 2026
Missouri gardeners in Zone 6b have a 33-week growing season for broccoli (March 22 to November 10). Missouri's spring and fall windows both work well for broccoli — some gardeners plant both successions for a long harvest. This guide gives exact dates for Missouri based on your local frost calendar.
Broccoli Planting Dates for Missouri
| Start seeds indoors | February 8–15 |
| Last frost (average) | March 22 |
| Transplant outdoors | February 22–March 4 |
| Direct sow outdoors | February 22–March 4 |
| Expect first harvest | April 23 – May 13 |
| Fall crop start | September 1–11 |
| Fall harvest | October 31 |
| First fall frost (average) | November 10 |
Dates above assume Zone 6b, the most common zone in Missouri. Gardeners in cooler St. Louis (Zone 6b) plant 1–2 weeks later; warmer Kansas City (Zone 6a) can plant 1–2 weeks earlier.
Growing Broccoli in Missouri's Climate
Missouri's moderate Zone 6b climate is well-suited to broccoli 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 broccoli harvest significantly in Missouri. 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 broccoli pests to watch for in Missouri include Cabbage Worm and Cabbage Looper. The first line of defense is companion planting: Onion and Garlic 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.
Broccoli Garden Calendar for Missouri
| Month | Task | Notes |
|---|---|---|
| January | — | Dormant season |
| February | Transplant outdoors | Soil temp must be 40°F+; nighttime lows above 50°F |
| March | Harden off seedlings | Set seedlings outdoors 1–2 hours daily, increasing gradually |
| April | First harvest window opens | Broccoli begins producing 60–80 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 broccoli; cover plants on frost nights |
| December | — | Dormant season |
Broccoli Growing Tips for Missouri Gardeners
- •For spring: start indoors 6 weeks before last frost and transplant outdoors 4 weeks before last frost.
- •For fall: start indoors in summer — count 10 weeks back from your first fall frost date.
- •Missouri's moderate climate supports succession planting — sow new transplants or seeds every 3 weeks during spring to extend the harvest window into fall.
- •Harvest heads before any yellow flowers open — once flowers show, flavor declines quickly.
Companion Planting for Broccoli in Missouri
In Missouri's moderate climate, planting broccoli with Onion and Garlic helps deter pests and improve soil. Avoid planting near Tomato and Pepper, which inhibit broccoli growth through root chemistry or shared pest pressure. See the full broccoli companion planting guide for the complete list.
Broccoli Planting Dates by City in Missouri
Top cities in Missouri — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant broccoli in Missouri?
In Missouri (Zone 6b), start broccoli seeds indoors around February 8–15 and transplant outdoors around February 22–March 4 — 4 weeks before the state's average last frost of March 22.
What is the last frost date in Missouri?
Missouri's average last frost date is March 22 in the state's most common Zone 6b. 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 broccoli year-round in Missouri?
broccoli is a cool-season crop in Missouri, 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 broccoli varieties grow best in Missouri?
For Missouri's Zone 6b, Waltham 29, Calabrese, and Green Magic perform well across conditions.
When do I start broccoli seeds indoors in Missouri?
Start broccoli seeds indoors in Missouri around February 8–15, which is 6 weeks before the state's average last frost of March 22. Use grow lights and keep soil temperatures at 70–75°F for fastest germination.