Frost Dates for Grand Rapids, MI 49508

Last spring frost May 10 · First fall frost October 5 · 148 frost-free days · USDA Zone 6a

Frost probability for 49508

Frost10%50%90%
Spring (last frost)May 27May 10April 22
Fall (first frost)September 22October 5October 17

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (35.4 km away); the 50% date is the median year.

Frost dates by ZIP code in Grand Rapids, MI

ZIPLast spring frost (50%)First fall frost (50%)Zone
49508May 10October 56a
49504May 10October 36a
49503May 10October 36a
49507May 10October 56a
49548May 10October 56a
49546May 11October 56a
49506May 10October 56a
49505May 10October 36a
49525May 10October 36a
49534May 5October 86a
49512May 10October 56a
49544May 5October 86a

Month by month in Grand Rapids

MonthWhat to do
JanuaryPlan your garden layout and order seeds. Research varieties suited to your frost dates.
FebruaryStart the slowest-growing crops indoors: onions, leeks, and celery (10–12 weeks before last frost).
MarchStart peppers and eggplant indoors 8–10 weeks before your last frost (around May 10). Start tomatoes about two weeks later, 6–8 weeks before last frost.
AprilStart herbs, basil, and squash indoors (4–6 weeks before frost). Direct sow peas, spinach, and lettuce if soil is workable.
MayLast frost around May 10. Transplant cold-hardy crops (broccoli, kale, cabbage). Harden off tomato and pepper seedlings.
JuneFrost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini.
JulySuccession plant lettuce and greens. Keep beds weeded and watered consistently.
AugustHarvest regularly to encourage production. Monitor for pests and disease.
SeptemberFirst fall frost approaching (around October 5). Transplant fall brassicas. Sow spinach, arugula, and radishes.
OctoberFirst frost around October 5. Harvest tomatoes and peppers before frost. Cover cold-hardy crops with row covers to extend the season.
NovemberHarvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year.
DecemberClean up spent plants. Add compost to beds. Rest, review, and plan next year's garden.

What grows in a 148-day season

Frequently Asked Questions

What is the last frost date for Grand Rapids, MI (ZIP 49508)?

The median last spring frost date for Grand Rapids, MI (ZIP code 49508) is around May 10. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area.

What is the first fall frost date in Grand Rapids, MI?

The median first fall frost date for Grand Rapids, MI is around October 5. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses.

How long is the growing season in Grand Rapids, MI?

The frost-free growing season in Grand Rapids is about 148 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side.

What USDA hardiness zone is Grand Rapids, MI?

Based on frost date patterns, Grand Rapids falls approximately in 6a. USDA hardiness zones are determined by average annual minimum winter temperatures and guide both plant selection and planting timing for your location.

When should I start tomatoes indoors in Grand Rapids, MI?

Start tomato seeds indoors 6–8 weeks before your last frost date (around May 10). For Grand Rapids, that's roughly March 15 to March 29. Transplant outdoors 1–2 weeks after your last frost.

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