Massachusetts planting calendar

When to plant leeks in Massachusetts — sow, transplant & harvest dates

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

Leeks planting timetable for Massachusetts

Stage	When in Massachusetts	Anchor
Start seeds indoors	mid-February (February 14)	10 weeks before the last frost (late April)
Transplant outside	late March (March 28)	28 days before the last frost (late April)
First harvest (estimate)	late July (July 26)	~120 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 Massachusetts's climate shifts the leeks dates

Massachusetts's last spring frost averages late April and first fall frost mid-October, which sets the whole planting clock. Massachusetts has a four-season New England climate, with the coast and Cape running a full zone warmer than the western Berkshires. Sow early — leeks bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Leeks are among the hardiest alliums — established plants tolerate temperatures as low as -10 °C, making them a reliable overwintering crop in zones 5–9. Start seeds indoors 10–12 weeks before last frost, transplanting pencil-thick seedlings into 15 cm (6-inch) deep holes or trenches to blanch the stems; backfill gradually as plants grow. Early-season varieties mature in around 90 days; late-season types take up to 150 days and deliver the best cold-hardiness for autumn and winter harvest.

Frost-risk note

Don't plant before late April — a hard freeze can still set young plants back. In the Berkshire hills in the west (zone 5b) the safe date runs a week or two later.

Regional variation within Massachusetts

the Berkshire hills in the west (zone 5b) runs roughly 1-2 weeks behind the state average; Cape Cod and the islands (zone 7b) can plant 1-2 weeks earlier.

Boston — USDA zone 7a
Worcester — USDA zone 6a
Springfield — USDA zone 6b
Cape Cod — USDA zone 7b

What else to plant in Massachusetts 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: 7-25 °C (45-77 °F).
Spacing: 6 inches (15 cm) between plants.
Days to harvest: ~120 days from planting out.

Frequently asked questions

When is the best time to plant leeks in Massachusetts?

In Massachusetts (mostly USDA zone 6b), sow leeks indoors around mid-February, transplant outdoors late March (before the last frost, late April), and harvest from late July. Leeks 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 Massachusetts?

Most of Massachusetts sits in USDA hardiness zone 6b, with the state spanning roughly 5b-7b from the Berkshire hills in the west (zone 5b) to Cape Cod and the islands (zone 7b). The last spring frost averages late April and the first fall frost mid-October.

Can you grow leeks in Massachusetts?

Yes. Massachusetts's dominant zone 6b supports leeks — the key is timing. Leeks 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 Massachusetts?

the Berkshire hills in the west (zone 5b) runs roughly 1-2 weeks behind the state average; Cape Cod and the islands (zone 7b) can plant 1-2 weeks earlier.

What else can I plant in Massachusetts 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.