Maine planting calendar

When to plant celery in Maine — sow, transplant & harvest dates

Maine is mostly USDA zone 5a (range 3b-6a). Dates below are derived from celery's frost tolerance and Maine's frost window — not generic national averages.

Celery planting timetable for Maine

Stage	When in Maine	Anchor
Start seeds indoors	early March (March 6)	10 weeks before the last frost (mid-May)
Transplant outside	early May (May 1)	14 days before the last frost (mid-May)
First harvest (estimate)	late August (August 24)	~115 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 Maine's climate shifts the celery dates

Maine's last spring frost averages mid-May and first fall frost late September, which sets the whole planting clock. Maine is a short-season cold-climate state, milder along the coast and noticeably colder in the northern and mountain interior. Sow early — celery bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Celery is one of the most demanding cool-season crops: it germinates slowly at 15-21 °C and needs 10-12 weeks of indoor growing time before transplanting out 2-4 weeks before the last spring frost. Temperatures below 10 °C for more than 10 consecutive days can trigger premature bolting, so protect young transplants with row cover in cold snaps. In zones 9-10 celery is typically grown as a winter/spring crop, started in late summer; in zones 3-6 the short cool window before summer heat sets in makes consistent irrigation and blanching (hilling or wrapping stems) essential for tender, mild stalks.

Frost-risk note

Don't plant before mid-May — a hard freeze can still set young plants back. In the far north Aroostook County interior (zone 3b) the safe date runs a week or two later.

Regional variation within Maine

the far north Aroostook County interior (zone 3b) runs roughly 1-2 weeks behind the state average; the southern coast around Portland (zone 6a) can plant 1-2 weeks earlier.

Portland — USDA zone 6a
Bangor — USDA zone 5a
Augusta — USDA zone 5b
Presque Isle — USDA zone 4a

What else to plant in Maine 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: 15-21 °C (60-70 °F).
Spacing: 8-12 inches (20-30 cm) between plants.
Days to harvest: ~115 days from planting out.

Frequently asked questions

When is the best time to plant celery in Maine?

In Maine (mostly USDA zone 5a), sow celery indoors around early March, transplant outdoors early May (before the last frost, mid-May), and harvest from late August. Celery 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 Maine?

Most of Maine sits in USDA hardiness zone 5a, with the state spanning roughly 3b-6a from the far north Aroostook County interior (zone 3b) to the southern coast around Portland (zone 6a). The last spring frost averages mid-May and the first fall frost late September.

Can you grow celery in Maine?

Yes. Maine's dominant zone 5a supports celery — the key is timing. Celery 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 Maine?

the far north Aroostook County interior (zone 3b) runs roughly 1-2 weeks behind the state average; the southern coast around Portland (zone 6a) can plant 1-2 weeks earlier.

What else can I plant in Maine 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.