When to plant kohlrabi in Providence, Rhode Island

March 14 – March 28

Transplant outdoors · typical Providence year

Climate basis: NOAA station Providence T F Green AP, RI (USW00014765), 7 mi (11 km) from downtown Providence (ZCTA 02903 centroid), elevation 60 ft, on the 1991–2020 climate normals. Transplant kohlrabi outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (April 11). One year in ten still freezes after April 23.

Last spring freezeApril 111-in-10 after Apr 23

First fall freezeOctober 301-in-10 before Oct 16

Frost-free season≈ 199 daysmedian at 32°F

Hard freeze, 28°Apr 1 – Nov 9kills even hardy greens

USDA zone7a0 to 5°F winter low — not frost timing

The Providence year

Start seeds indoorsJan 31 – Feb 14

Transplant outdoorsMar 14 – Mar 28

Fall plantingSep 4 – Oct 2

indoors under lights
in the garden
frost-free season
1-in-10 years still freeze to Apr 23

Kohlrabi in Providence · freeze context from Providence T F Green AP, RI, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Jan 31 – Feb 14

Sow 4–6 weeks before the set-out window opens (UNH: time from seed to transplant 4–6 weeks). Anchored to the median last spring freeze (Apr 11). University of New Hampshire Extension

Transplant outdoors

Mar 14 – Mar 28

UNH: safe to set out 4 weeks before the last frost; Purdue's hardy class allows 4–6 weeks before. The later UNH start is used. Anchored to the median last spring freeze (Apr 11). University of New Hampshire Extension · Purdue University Extension

Fall planting

Sep 4 – Oct 2

Purdue Table 2: plant fall kohlrabi at least 4–8 weeks before the first fall frost. Anchored to the median first fall freeze (Oct 30). Purdue University Extension

These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.

This week, not a typical year:

Crop rule sources (2)

University of New Hampshire Extension: Growing Vegetables: When to Plant Your Vegetable Garden [fact sheet] (accessed 2026-07-24)
Per-crop 'time from seed to transplant' and 'safe to set out in garden' relative to last frost.
Purdue University Extension: Indiana Vegetable Planting Calendar (HO-186-W) (accessed 2026-07-24)
Hardiness classes: hardy = plant 4-6 wk before last spring frost; semi-hardy = 2-4 wk before; tender = after average last frost; very tender = at least 2 wk after. Table 2: fall planting at least 4-8 wk before first fall frost.

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