Detroit, MI Frost Dates & Growing Season

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

Last spring frost
Apr 21
~50% chance of frost after
First fall frost
Oct 31
~50% chance of frost before
Growing season
193 days
frost-free stretch
USDA zone
6b
2023 hardiness map
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 7 Apr 21 May 6
First fall frost Nov 11 Oct 31 Oct 17
Hard freeze (28°F), median last Apr 8 · first Nov 9

Computed from NOAA 1991–2020 climate normals at the Detroit City Airport station (9 km from central Detroit). "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 Detroit

Computed from Detroit's own frost dates. Click any crop for the full zone-6 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Feb 24 – Mar 10 Apr 28 – May 5
🫑 Peppers Feb 10 – Feb 24 May 5 – May 12
🥬 Lettuce Mar 10 – Mar 24 Mar 24 – Apr 7 Mar 24 – Apr 21
🫛 Peas Mar 10 – Mar 24
🥕 Carrots Mar 31 – Apr 21
🥦 Broccoli Mar 3 – Mar 17 Mar 31 – Apr 14
🥬 Kale Mar 10 – Mar 24 Mar 24 – Apr 7 Mar 24 – Apr 7
🥒 Cucumbers Mar 24 – Mar 31 Apr 28 – May 5 Apr 28 – May 5
🥒 Zucchini Mar 24 – Mar 31 Apr 28 – May 5 Apr 28 – May 5
🫘 Green Beans (Bush) Apr 28 – May 5
🌽 Sweet Corn Apr 28 – May 5
🌿 Basil Mar 10 – Mar 24 Apr 28 – May 5 May 5 – May 12
🧄 Garlic Fall: Sep 19 – Oct 17

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 Detroit's dates automatically after a lookup.

Reading the season in Detroit

Roughly 193 frost-free days gives Detroit gardeners room for nearly every common vegetable. Warm-season crops go out after Apr 21; a fall garden sown in late summer matures comfortably before the Oct 31 frost.

Frequently asked questions

When is the last frost in Detroit, MI?

The average last spring frost in Detroit is around Apr 21, 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 Detroit, MI?

The average first fall frost in Detroit arrives around Oct 31. 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 Detroit?

About 193 frost-free days on average, from Apr 21 to Oct 31. That fits nearly all common vegetables, though the longest-season melons and sweet potatoes benefit from transplants.

What USDA zone is Detroit in?

USDA zone 6b 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.