Seed Starting Calendar for Massachusetts

Q: When is the last frost in Massachusetts?

It depends on the station. The earliest median last spring freeze in Massachusetts is April 4 at Boston Logan Intl Airport; the latest is May 17 at E Hawley. A median is a coin flip: at Worcester the last 32°F freeze comes after April 23 in half of years, and has passed by May 5 in 9 of 10 years (NOAA 1991 to 2020 normals).

Q: When can I plant tomatoes outside in Massachusetts?

UNH Extension sets tomatoes out 1 to 2 weeks after the last frost, which at Worcester is Apr 30 to May 7 in 2027. Tomatoes are frost tender, so the date to watch is May 5, when 9 of 10 springs at Worcester have had their last 32°F night. Hardening off starts two weeks before setting out (Apr 16 to Apr 30).

Q: How many weeks before the last frost do I start peppers and eggplant?

UNH Extension gives 8 to 10 weeks from seed to transplant for both, and sets peppers out 2 weeks after the last frost and eggplant 2 to 3 weeks after, so the sowing date is 6 to 8 weeks before the median last frost. At Worcester that is Feb 26 to Mar 12 for peppers.

Q: How long do seedlings need to harden off?

About two weeks. University of Missouri Extension: "Hardening should be started about two weeks before planting in the garden." University of Minnesota Extension adds that seedlings should go out on a cloudy day or in the late afternoon.

Median last frost from Apr 11 to May 12 across Massachusetts

NOAA stations

Median last frost, Worcester

Apr 23

Passed in 9 of 10 years

May 5

Last frost

Last spring frost dates in Massachusetts

Boston Logan reaches its median last frost around Apr 4, Worcester up on its hills around Apr 23, and Pittsfield in the Berkshires around May 5, a month apart across one state.

Three dates per station from the NOAA 1991 to 2020 normals. The median is the date half of springs run past. The last column is the date the last 32°F night has passed by in 9 years out of 10, the one to hold tender transplants for.

Station	Elevation	Early (1 in 10 years later than this)	Median last frost	Passed in 9 of 10 years	Median first fall frost
BostonBoston Logan Intl Airport, USW00014739	12 ft	Mar 25	Apr 4	Apr 17	Nov 9
Nantucket Memorial AirportNantucket Memorial Airport, USW00014756	45 ft	Apr 2	Apr 13	Apr 27	Nov 8
WorcesterWorcester Regional Airport, USW00094746	1,000 ft	Apr 11	Apr 23	May 5	Oct 21
New Bedford Municipal AirportNew Bedford Municipal Airport, USW00094726	80 ft	Apr 17	Apr 29	May 15	Oct 15
PittsfieldPittsfield Municipal Airport, USW00014763	1,194 ft	Apr 23	May 5	May 21	Oct 5

Crop chart

When to start seeds in Massachusetts, spring 2027

Counted back from the median last frost at Worcester, April 23. Pick another station to redraw the chart for it.

Start indoorsHarden offSet outSow outdoorsMedian last frostLast freeze passed in 9 of 10 years

Every crop, counted from a median last frost of April 23
Crop	Start indoors	Set out	Sow outdoors	Frost class
Tomato	Mar 5 to Mar 19	Apr 30 to May 7		Tender, very tender
Pepper	Feb 26 to Mar 12	May 7 to May 14		Tender, very tender
Eggplant	Feb 26 to Mar 12	May 7 to May 14		Tender, very tender
Basil	Mar 12 to Mar 26	May 7 to May 14		Tender
Celery	Jan 29 to Feb 12	Apr 23 to Apr 30		Tender
Cucumber	Apr 2 to Apr 9	Apr 30 to May 7	Apr 23 to Apr 30	Tender
Summer squash	Apr 9 to Apr 16	May 7 to May 14	Apr 23 to Apr 30	Tender
Winter squash	Apr 9 to Apr 16	May 7 to May 14	May 7 to May 14	Tender, very tender
Pumpkin	Apr 9 to Apr 16	May 7 to May 14	May 7 to May 14	Tender, very tender
Melon (cantaloupe)	Apr 9 to Apr 16	May 7 to May 14		Tender, very tender
Watermelon	Apr 2 to Apr 16	May 7 to May 14		Tender, very tender
Onion (from seed)	Jan 15 to Jan 29	Mar 26 to Apr 2		Hardy
Leek	Jan 15 to Jan 29	Mar 26 to Apr 2		Hardy
Parsley	Jan 22 to Jan 29	Apr 2 to Apr 9		Half-hardy
Broccoli	Feb 12 to Feb 26	Mar 26 to Apr 9		Hardy
Brussels sprouts	Feb 12 to Feb 26	Mar 26 to Apr 9		Hardy
Cabbage	Feb 12 to Feb 26	Mar 26 to Apr 2		Hardy
Cauliflower	Feb 26 to Mar 12	Apr 9 to Apr 16		Half-hardy
Kale	Feb 12 to Feb 26	Mar 26 to Apr 2		Hardy
Lettuce	Feb 19 to Feb 26	Mar 26 to Apr 2		Hardy
Swiss chard	Feb 26 to Mar 12	Apr 9 to Apr 16	Mar 26 to Apr 2	Half-hardy
Spinach	Jan 29 to Feb 12	Mar 12 to Apr 2	Mar 26 to Apr 9	Hardy
Peas			Mar 26 to Apr 9	Hardy
Radish			Mar 26 to Apr 9	Hardy
Carrot			Apr 9 to Apr 23	Half-hardy
Beet			Apr 9 to Apr 23	Half-hardy
Beans			Apr 23 to Apr 30	Tender
Sweet corn			Apr 23 to Apr 30	Tender

Six square pots of dark compost seen from above, each holding a single seedling with two narrow seed leaves — Tomato seedlings at the seed leaf stage, one to a pot. The University of Minnesota Extension holds off on fertilizer until a seedling has several sets of true leaves, then feeds at quarter strength once a week. “Tomato Seedlings (49768696597)” by Amanda Slater from Coventry, West Midlands, UK, CC BY-SA 2.0

Extension guide

What UMass Extension Center for Agriculture, Food, and the Environment advises

UMass Extension Center for Agriculture, Food, and the Environment publishes the planting guide Massachusetts gardeners work from, Vegetable Planting Chart.

“These vegetables are known as “warm weather crops”. Transplant seedlings into the garden only after all danger of frost has passed.”

UMass Extension Center for Agriculture, Food, and the Environment, Vegetable Planting Chart, quoted exactly.

“In many areas of Massachusetts, the last frost date is usually around May 15th. Count back the number of weeks from when each vegetable is to be transplanted into the garden. That will tell you when to start your seeds indoors.”

UMass Extension Center for Agriculture, Food, and the Environment, Starting Seeds Indoors, quoted exactly.

“4-7 weeks Broccoli, brussel sprouts, cabbage and cauliflower”

UMass Extension Center for Agriculture, Food, and the Environment, on broccoli, quoted exactly.

“Since melons require a long, warm growing season, seeds should be started indoors four to five weeks prior to planting outdoors.”

UMass Extension Center for Agriculture, Food, and the Environment, on melon, quoted exactly.

Planting months

UMass Extension Center for Agriculture, Food, and the Environment planting months for Massachusetts

The extension also publishes planting months by region. Each filled cell is a month the guide gives for planting that crop.

Massachusetts (earlier in eastern and southern, later in western and northern)

Crop	Mar	Apr	May	Jun	Jul	Aug
beets	Mar	Apr	May	Jun	Jul	Aug
carrots	Mar	Apr	May	Jun	Jul	Aug
lettuce	Mar	Apr	May	Jun	Jul	Aug
onions	Mar	Apr	May
parsley	Mar	Apr	May
peas	Mar	Apr			Jul
radishes	Mar	Apr	May	Jun	Jul	Aug
spinach	Mar	Apr	May	Jun	Jul	Aug
swiss chard		Apr	May	Jun	Jul	Aug
broccoli		Apr	May	Jun	Jul	Aug
brussels sprouts			May	Jun
cabbage		Apr	May	Jun	Jul	Aug
cauliflower		Apr	May	Jun	Jul	Aug
celery			May	Jun
kale and collards			May	Jun	Jul
leeks			May	Jun
basil			May	Jun	Jul
beans			May	Jun	Jul
corn			May	Jun
cucumbers			May	Jun	Jul
melons			May	Jun
pumpkins			May	Jun
summer squash			May	Jun	Jul
winter squash			May	Jun
eggplant			May	Jun
peppers			May	Jun
tomatoes			May	Jun

Planting months from UMass Extension Center for Agriculture, Food, and the Environment, Vegetable Planting Chart, read 2026-09-21. Tomatoes in Massachusetts: May and June.

A gardener kneeling beside a raised bed setting a young tomato plant into dark soil, an empty nursery pot beside her — Setting out a tomato in June at a community garden. Tender crops go out after the last frost, and after a week or two of hardening off outdoors. “Volunteer planting heirloom tomato (4704185147)”, Pacific Southwest Region 5, Public domain

Seed starting questions for Massachusetts

When should I start seeds indoors in Massachusetts?

Count back from the median last frost where you garden. At Worcester (Worcester Regional Airport) that date is April 23, so for spring 2027 onions start indoors Jan 15 to Jan 29, peppers Feb 26 to Mar 12 and tomatoes Mar 5 to Mar 19. Across Massachusetts's 65 NOAA stations the median last frost runs from Apr 11 to May 12 for the middle 90 percent, so a garden near E Hawley starts later than one near Boston Logan Intl Airport.

When is the last frost in Massachusetts?

When can I plant tomatoes outside in Massachusetts?

What months do I plant vegetables in Massachusetts?

What does UMass Extension Center for Agriculture, Food, and the Environment say about planting dates in Massachusetts?

How many weeks before the last frost do I start peppers and eggplant?

How long do seedlings need to harden off?

Why do seed starting dates differ across Massachusetts?

Frost dates from NOAA NCEI U.S. Climate Normals 1991-2020, annual/seasonal, by station (v1.0.1). Planting guidance from UMass Extension Center for Agriculture, Food, and the Environment, quoted exactly. Seed starting weeks from UNH Cooperative Extension. Compiled 2026-09-21.

First frost in MassachusettsThe other end of the season: when fall frost ends the tender crops.Soil temperatureBeans, corn and squash sown direct wait on warm soil as well as the last frost.Massachusetts lawn care calendarSpring seeding, feeding and mowing dates on the same climate.Fall planting calendarGarlic, cool season crops and a second sowing window in the fall.Frost dates by ZIPFirst and last frost odds for any address.