Kentucky planting calendar

When to plant rhubarb in Kentucky — sow, transplant & harvest dates

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

Rhubarb planting timetable for Kentucky

Stage	When in Kentucky	Anchor
Direct-sow outside	late March (March 25)	21 days before the last frost (mid-April)
First harvest (estimate)	late September (September 23)	~547 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 Kentucky's climate shifts the rhubarb dates

Kentucky's last spring frost averages mid-April and first fall frost mid-October, which sets the whole planting clock. Kentucky has a mild four-season climate with a long, humid summer and a winter that rarely tests hardy perennials. Wait for warm soil — rhubarb stall in cold ground even after the air warms, so don't rush them out.

Rhubarb is planted as divisions or crowns in early spring while the soil is still cool, 2-3 weeks before the last frost; it is extremely cold-hardy and actually requires winter chilling to break dormancy (reliably hardy to zone 3, marginal in zones 9-10 where inadequate chilling reduces vigour). Do not harvest in year one; take only 2-3 stalks per plant in year two; harvest freely from year three onward, always leaving at least 3-4 strong stalks per crown. Never eat the leaves — rhubarb foliage contains toxic oxalates at harmful concentrations.

Frost-risk note

Don't plant before mid-April — a hard freeze can still set young plants back. In the eastern Appalachian highlands (zone 6a) the safe date runs a week or two later.

Regional variation within Kentucky

the eastern Appalachian highlands (zone 6a) runs roughly 1-2 weeks behind the state average; the Ohio River valley around Louisville (zone 7b) can plant 1-2 weeks earlier.

Louisville — USDA zone 7a
Lexington — USDA zone 6b
Bowling Green — USDA zone 7a
Covington — USDA zone 6b

What else to plant in Kentucky around then

Pair the post-frost slot with other warm-season crops — peppers, beans, squash, and cucumbers.

Quick-grow guide

Sun: Full sun — 6+ hours direct (tolerates light afternoon shade in hot zones).
Soil temperature for germination: Soil 4-10 °C (40-50 °F) at crown planting.
Spacing: 36-48 inches (90-120 cm) between plants.
Days to harvest: ~547 days from planting out.

Frequently asked questions

When is the best time to plant rhubarb in Kentucky?

In Kentucky (mostly USDA zone 6b), direct-sow rhubarb late March (before the last frost, mid-April), and harvest from late September. Rhubarb are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

What USDA zone is Kentucky?

Most of Kentucky sits in USDA hardiness zone 6b, with the state spanning roughly 6a-7b from the eastern Appalachian highlands (zone 6a) to the Ohio River valley around Louisville (zone 7b). The last spring frost averages mid-April and the first fall frost mid-October.

Can you grow rhubarb in Kentucky?

Yes. Kentucky's dominant zone 6b supports rhubarb — the key is timing. Rhubarb are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

Does the planting date change across Kentucky?

the eastern Appalachian highlands (zone 6a) runs roughly 1-2 weeks behind the state average; the Ohio River valley around Louisville (zone 7b) can plant 1-2 weeks earlier.

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

Pair the post-frost slot with other warm-season crops — peppers, beans, squash, and cucumbers.

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.