When to Plant Zucchini in Missouri
Published: April 21, 2026
Missouri gardeners in Zone 6b have a 33-week growing season for zucchini (March 22 to November 10). The moderate climate supports a full warm-season crop plus an often-productive fall crop. This guide gives exact dates for Missouri based on your local frost calendar.
Zucchini Planting Dates for Missouri
| Start seeds indoors | March 1–8 |
| Last frost (average) | March 22 |
| Transplant outdoors | March 29–April 8 |
| Direct sow outdoors | March 29–April 8 |
| Expect first harvest | May 13 – May 23 |
| Fall crop start | September 15–25 |
| Fall harvest | October 30 |
| 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 Zucchini in Missouri's Climate
Missouri's moderate Zone 6b climate is well-suited to zucchini 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 zucchini 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 zucchini pests to watch for in Missouri include Squash Vine Borer and Squash Bug. The first line of defense is companion planting: Corn and Bush Beans 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.
Zucchini Garden Calendar for Missouri
| Month | Task | Notes |
|---|---|---|
| January | — | Dormant season |
| February | — | Dormant season |
| March | Transplant outdoors | Soil temp must be 65°F+; nighttime lows above 50°F |
| April | — | Dormant season |
| May ← | First harvest window opens | Zucchini begins producing 45–55 days after transplant |
| June | Peak growth; water 1 inch/week | Monitor for pests daily; stake or support as needed |
| July | Start fall crop seeds | Fall transplants go in 8 weeks before first frost |
| 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 zucchini; cover plants on frost nights |
| December | — | Dormant season |
Zucchini Growing Tips for Missouri Gardeners
- •Start with just 1–2 plants — zucchini are so productive that more is rarely needed.
- •Harvest at 6–8 inches for peak flavor; zucchini left on the plant signals it to stop producing.
- •Missouri's moderate climate supports succession planting — sow new transplants or seeds every 3 weeks during spring to extend the harvest window into fall.
- •Plant a backup crop in early July to replace any vine borer losses in the eastern US.
Companion Planting for Zucchini in Missouri
In Missouri's moderate climate, planting zucchini with Corn and Bush Beans helps deter pests and improve soil. Avoid planting near Potato and Fennel, which inhibit zucchini growth through root chemistry or shared pest pressure. See the full zucchini companion planting guide for the complete list.
Zucchini 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 zucchini in Missouri?
In Missouri (Zone 6b), start zucchini seeds indoors around March 1–8 and transplant outdoors around March 29–April 8 — 1 weeks after 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 zucchini year-round in Missouri?
Not year-round — Missouri's cold season stops zucchini production. The zucchini season runs March 22 to November 10, roughly 33 weeks. A fall crop extends harvest into late autumn.
What zucchini varieties grow best in Missouri?
For Missouri's Zone 6b, Black Beauty, Costata Romanesco, and Yellow Crookneck are widely adaptable.
When do I start zucchini seeds indoors in Missouri?
Start zucchini seeds indoors in Missouri around March 1–8, which is 3 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.