Indiana planting calendar

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

Indiana is mostly USDA zone 6a (range 5b-7a). Dates below are derived from radishes's frost tolerance and Indiana's frost window — not generic national averages.

Radishes planting timetable for Indiana

Stage	When in Indiana	Anchor
Direct-sow outside	early April (April 4)	21 days before the last frost (late April)
First harvest (estimate)	early May (May 2)	~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 Indiana's climate shifts the radishes dates

Indiana's last spring frost averages late April and first fall frost mid-October, which sets the whole planting clock. Indiana is a temperate Midwest state with a reliable warm summer and a southern tier that runs a full zone milder than the north. 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 late April — a hard freeze can still set young plants back. In the northern lake-effect counties (zone 5b) the safe date runs a week or two later.

Regional variation within Indiana

the northern lake-effect counties (zone 5b) runs roughly 1-2 weeks behind the state average; the Ohio River valley near Evansville (zone 7a) can plant 1-2 weeks earlier.

Indianapolis — USDA zone 6a
Fort Wayne — USDA zone 5b
Evansville — USDA zone 7a
South Bend — USDA zone 6a

What else to plant in Indiana 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 Indiana?

In Indiana (mostly USDA zone 6a), direct-sow radishes early April (before the last frost, late April), and harvest from early 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 Indiana?

Most of Indiana sits in USDA hardiness zone 6a, with the state spanning roughly 5b-7a from the northern lake-effect counties (zone 5b) to the Ohio River valley near Evansville (zone 7a). The last spring frost averages late April and the first fall frost mid-October.

Can you grow radishes in Indiana?

Yes. Indiana'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 Indiana?

the northern lake-effect counties (zone 5b) runs roughly 1-2 weeks behind the state average; the Ohio River valley near Evansville (zone 7a) can plant 1-2 weeks earlier.

What else can I plant in Indiana 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.