Maine planting calendar

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

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

Asparagus planting timetable for Maine

Stage	When in Maine	Anchor
Direct-sow outside	late April (April 24)	21 days before the last frost (mid-May)
First harvest (estimate)	late April (April 23)	~730 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 Maine's climate shifts the asparagus 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. Wait for warm soil — asparagus stall in cold ground even after the air warms, so don't rush them out.

Asparagus is almost always established from year-old crowns rather than seed; plant them in a prepared trench 20-30 cm deep as soon as the soil can be worked in early spring, 2-3 weeks before the last frost. Do not harvest at all in year one, harvest sparingly for 2-3 weeks in year two, and from year three onward you can take a full 6-8 week spring harvest. Crowns are reliably cold-hardy to zone 3 but require winter dormancy — they are poorly suited to zones 10-11 where winters are too warm to meet the chilling requirement.

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

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

Quick-grow guide

Sun: Full sun — 6-8 hours direct.
Soil temperature for germination: Soil 10-18 °C (50-65 °F) at crown planting.
Spacing: 12-18 inches (30-45 cm) between plants.
Days to harvest: ~730 days from planting out.

Frequently asked questions

When is the best time to plant asparagus in Maine?

In Maine (mostly USDA zone 5a), direct-sow asparagus late April (before the last frost, mid-May), and harvest from late April. Asparagus 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 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 asparagus in Maine?

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

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.