Ohio planting calendar

When to plant kohlrabi in Ohio — sow, transplant & harvest dates

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

Kohlrabi planting timetable for Ohio

Stage	When in Ohio	Anchor
Start seeds indoors	late March (March 21)	5 weeks before the last frost (late April)
Transplant outside	early April (April 4)	21 days before the last frost (late April)
First harvest (estimate)	late May (May 29)	~55 days from transplant

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 Ohio's climate shifts the kohlrabi dates

Ohio's last spring frost averages late April and first fall frost mid-October, which sets the whole planting clock. Ohio has a temperate, fairly uniform Midwest climate. Most of the state sits in zone 6 with a dependable warm summer. Sow early — kohlrabi bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Kohlrabi is a fast-maturing brassica that tolerates light frost down to about -4 °C but turns woody and pithy when daytime temperatures exceed 27 °C; transplant or direct-sow 3–4 weeks before the last spring frost for a summer harvest, or time a second sowing so plants mature in the cool days of early autumn. Harvest promptly when the swollen stem reaches 5–7 cm (2–3 inches) in diameter — larger bulbs become fibrous. Succession-sow every 3 weeks to extend the harvest window.

Frost-risk note

Don't plant before late April — a hard freeze can still set young plants back. In the northeast snowbelt and Allegheny foothills (zone 5b) the safe date runs a week or two later.

Regional variation within Ohio

the northeast snowbelt and Allegheny foothills (zone 5b) runs roughly 1-2 weeks behind the state average; the Ohio River valley near Cincinnati (zone 6b) can plant 1-2 weeks earlier.

Columbus — USDA zone 6b
Cleveland — USDA zone 6b
Cincinnati — USDA zone 6b
Toledo — USDA zone 6a
Akron — USDA zone 6a

What else to plant in Ohio 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: 6-9 inches (15-23 cm) between plants.
Days to harvest: ~55 days from planting out.

Frequently asked questions

When is the best time to plant kohlrabi in Ohio?

In Ohio (mostly USDA zone 6a), sow kohlrabi indoors around late March, transplant outdoors early April (before the last frost, late April), and harvest from late May. Kohlrabi 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 Ohio?

Most of Ohio sits in USDA hardiness zone 6a, with the state spanning roughly 5b-6b from the northeast snowbelt and Allegheny foothills (zone 5b) to the Ohio River valley near Cincinnati (zone 6b). The last spring frost averages late April and the first fall frost mid-October.

Can you grow kohlrabi in Ohio?

Yes. Ohio's dominant zone 6a supports kohlrabi — the key is timing. Kohlrabi 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 Ohio?

the northeast snowbelt and Allegheny foothills (zone 5b) runs roughly 1-2 weeks behind the state average; the Ohio River valley near Cincinnati (zone 6b) can plant 1-2 weeks earlier.

What else can I plant in Ohio 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.