St. Louis, MO Frost Dates & Growing Season

The two dates every St. Louis garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
Apr 1
~50% chance of frost after
First fall frost
Nov 4
~50% chance of frost before
Growing season
217 days
frost-free stretch
USDA zone
7a
2023 hardiness map
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Mar 14 Apr 1 Apr 18
First fall frost Nov 21 Nov 4 Oct 24
Hard freeze (28°F), median last Mar 22 · first Nov 15

Computed from NOAA 1991–2020 climate normals at the St Louis Sci Ctr station (6 km from central St. Louis). "Safe" means frost past that date happens only about one year in ten. Your exact garden can still run days either way with elevation and terrain — check your own ZIP with the frost date lookup.

Planting windows for St. Louis

Computed from St. Louis's own frost dates. Click any crop for the full zone-7 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Feb 4 – Feb 18 Apr 8 – Apr 15
🫑 Peppers Jan 21 – Feb 4 Apr 15 – Apr 22
🥬 Lettuce Feb 18 – Mar 4 Mar 4 – Mar 18 Mar 4 – Apr 1
🫛 Peas Feb 18 – Mar 4
🥕 Carrots Mar 11 – Apr 1
🥦 Broccoli Feb 11 – Feb 25 Mar 11 – Mar 25
🥬 Kale Feb 18 – Mar 4 Mar 4 – Mar 18 Mar 4 – Mar 18
🥒 Cucumbers Mar 4 – Mar 11 Apr 8 – Apr 15 Apr 8 – Apr 15
🥒 Zucchini Mar 4 – Mar 11 Apr 8 – Apr 15 Apr 8 – Apr 15
🫘 Green Beans (Bush) Apr 8 – Apr 15
🌽 Sweet Corn Apr 8 – Apr 15
🌿 Basil Feb 18 – Mar 4 Apr 8 – Apr 15 Apr 15 – Apr 22
🧄 Garlic Fall: Sep 23 – Oct 21

Want this for all 50 crops, or as a printable seed-shelf schedule? Use the planting calendar and the seed starting scheduler — both can use St. Louis's dates automatically after a lookup.

Reading the season in St. Louis

With roughly 217 frost-free days, St. Louis gardens fit long-season crops — melons, winter squash, sweet potatoes — with room left for spring and fall rounds of greens and roots. The first frost around Nov 4 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in St. Louis, MO?

The average last spring frost in St. Louis is around Apr 1, based on 1991–2020 climate normals. That's a median — about half of years see a later frost, so tender crops are safest going out a week or two after this date.

When is the first frost in St. Louis, MO?

The average first fall frost in St. Louis arrives around Nov 4. Crops still in the garden need to mature before then, and frost-tender plants need harvesting or protection as the date approaches.

How long is the growing season in St. Louis?

About 217 frost-free days on average, from Apr 1 to Nov 4. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is St. Louis in?

USDA zone 7a on the 2023 Plant Hardiness Zone Map. Note that zones describe winter cold, not frost timing — these frost dates are the numbers to plan plantings around.