Connecticut planting calendar

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

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

Kohlrabi planting timetable for Connecticut

Stage	When in Connecticut	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 Connecticut's climate shifts the kohlrabi dates

Connecticut's last spring frost averages late April and first fall frost mid-October, which sets the whole planting clock. Connecticut has a classic four-season New England climate with a coastal strip a full zone milder than the inland hills. 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 northwest hills near Litchfield (zone 5b) the safe date runs a week or two later.

Regional variation within Connecticut

the northwest hills near Litchfield (zone 5b) runs roughly 1-2 weeks behind the state average; the Long Island Sound shoreline (zone 7b) can plant 1-2 weeks earlier.

Hartford — USDA zone 6b
New Haven — USDA zone 7a
Bridgeport — USDA zone 7a
Stamford — USDA zone 7a

What else to plant in Connecticut 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 Connecticut?

In Connecticut (mostly USDA zone 6b), 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 Connecticut?

Most of Connecticut sits in USDA hardiness zone 6b, with the state spanning roughly 5b-7b from the northwest hills near Litchfield (zone 5b) to the Long Island Sound shoreline (zone 7b). The last spring frost averages late April and the first fall frost mid-October.

Can you grow kohlrabi in Connecticut?

Yes. Connecticut's dominant zone 6b 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 Connecticut?

the northwest hills near Litchfield (zone 5b) runs roughly 1-2 weeks behind the state average; the Long Island Sound shoreline (zone 7b) can plant 1-2 weeks earlier.

What else can I plant in Connecticut 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.