Michigan planting calendar

When to plant radishes in Michigan — sow, transplant & harvest dates

Michigan is mostly USDA zone 6a (range 4a-6b). Dates below are derived from radishes's frost tolerance and Michigan's frost window — not generic national averages.

Radishes planting timetable for Michigan

Stage	When in Michigan	Anchor
Direct-sow outside	late April (April 24)	21 days before the last frost (mid-May)
First harvest (estimate)	late May (May 22)	~28 days from direct sow

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why Michigan's climate shifts the radishes dates

Michigan's last spring frost averages mid-May and first fall frost early October, which sets the whole planting clock. Michigan is moderated by the Great Lakes, which create a milder fruit belt along Lake Michigan and a colder interior Upper Peninsula. Sow early — radishes bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Radishes are the fastest root crop — spring types mature in 22-30 days from direct sowing, making them ideal row-markers alongside slower crops. Sow 2-4 weeks before the last spring frost as soon as soil can be worked; they bolt and become pithy and peppery hot if left too long in warming soil. Succession-sow every 7-10 days for a continuous harvest; daikon and winter types sown in late summer take 50-70 days and tolerate heavier frost.

Frost-risk note

Don't plant before mid-May — a hard freeze can still set young plants back. In the western Upper Peninsula interior (zone 4a) the safe date runs a week or two later.

Regional variation within Michigan

the western Upper Peninsula interior (zone 4a) runs roughly 1-2 weeks behind the state average; the southeast near Detroit and the Lake Michigan fruit belt (zone 6b) can plant 1-2 weeks earlier.

Detroit — USDA zone 6b
Grand Rapids — USDA zone 6a
Lansing — USDA zone 5b
Marquette — USDA zone 5a
Traverse City — USDA zone 6a

What else to plant in Michigan around then

The same early window suits peas, lettuce, spinach, and onion sets.

Quick-grow guide

Sun: Full sun — 6+ hours direct.
Soil temperature for germination: 7-29 °C (45-85 °F).
Spacing: 2-3 inches (5-8 cm) between plants.
Days to harvest: ~28 days from planting out.

Frequently asked questions

When is the best time to plant radishes in Michigan?

In Michigan (mostly USDA zone 6a), direct-sow radishes late April (before the last frost, mid-May), and harvest from late May. Radishes are half-hardy — young plants shrug off a light frost but not a hard freeze, so sowing can start a couple of weeks before the last spring frost.

What USDA zone is Michigan?

Most of Michigan sits in USDA hardiness zone 6a, with the state spanning roughly 4a-6b from the western Upper Peninsula interior (zone 4a) to the southeast near Detroit and the Lake Michigan fruit belt (zone 6b). The last spring frost averages mid-May and the first fall frost early October.

Can you grow radishes in Michigan?

Yes. Michigan's dominant zone 6a supports radishes — the key is timing. Radishes are half-hardy — young plants shrug off a light frost but not a hard freeze, so sowing can start a couple of weeks before the last spring frost.

Does the planting date change across Michigan?

the western Upper Peninsula interior (zone 4a) runs roughly 1-2 weeks behind the state average; the southeast near Detroit and the Lake Michigan fruit belt (zone 6b) can plant 1-2 weeks earlier.

What else can I plant in Michigan around the same time?

The same early window suits peas, lettuce, spinach, and onion sets.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.