Frost dates for 01450 — Groton, MA
Last spring frostApr 29median date
First fall frostOct 8median date
Growing season162 daysfrost-free
Hardiness zone6aZone 6a
How Groton compares
- In 8 years out of 10, the last spring frost in Groton falls between April 16 and May 11, a 25-day window. The first fall frost falls between September 28 and October 25.
- The median last frost is 2 days later than the Massachusetts median of Apr 27.
- Its 162-day growing season is longer than 30% of the 510 Massachusetts places with a regular frost season (state median 169 days).
- The last frost is typical for zone 6a, where the median is Apr 29.
- The weather station records an average of 149 nights a year at or below 32°F.
- Groton shares its weather station with Nashua, NH, 17 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 16 |
| 50% (median) | April 29 |
| 10% (safe for tender plants) | May 11 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 28 |
| 50% (median) | October 8 |
| 90% (late) | October 25 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Groton, MA
Frost dates for 01450 — Groton, MA — last frost Apr 29, first frost Oct 8, zone 6a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Feb 4 to Feb 18Transplant outside: Apr 1 to Apr 15
Start indoors: Feb 18 to Mar 4Transplant outside: May 13 to May 27
Start indoors: Feb 18 to Mar 4Transplant outside: May 13 to May 27
Start indoors: Mar 4 to Mar 18Transplant outside: May 6 to May 20
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 8 to Apr 22Sow outdoors: Apr 1 to May 6Plant for fall: Aug 13 to Sep 10
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 1 to Apr 15Sow outdoors: Apr 1 to Apr 15Plant for fall: Jul 30 to Aug 20
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 15 to Apr 29Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 8 to Apr 22Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 15 to Apr 29Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 18 to Apr 1Transplant outside: May 20 to Jun 3Sow outdoors: May 20 to Jun 3
Start indoors: Mar 18 to Apr 1Transplant outside: May 6 to May 20
Sow outdoors: Mar 18 to Apr 8Plant for fall: Jul 16 to Aug 6
Sow outdoors: Mar 18 to Apr 8Plant for fall: Aug 13 to Sep 3
Sow outdoors: Mar 25 to May 6Plant for fall: Aug 27 to Sep 17
Start indoors: Apr 1 to Apr 8Transplant outside: May 13 to May 20Sow outdoors: May 6 to May 20Plant for fall: Jul 23 to Aug 6
Start indoors: Apr 1 to Apr 8Sow outdoors: May 6 to May 20Plant for fall: Jul 30 to Aug 13
Start indoors: Apr 1 to Apr 8Sow outdoors: May 6 to May 20
Start indoors: Apr 1 to Apr 8Transplant outside: May 13 to May 27
Sow outdoors: Apr 8 to May 6Plant for fall: Jul 16 to Jul 30
Sow outdoors: Apr 8 to May 6Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 8 to Apr 29
Sow outdoors: Apr 15 to May 13Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 15 to May 6Plant for fall: Aug 13 to Sep 3
Sow outdoors: May 6 to May 27Plant for fall: Jul 23 to Aug 6
Sow outdoors: May 6 to May 20
Transplant outside: May 13 to Jun 3
Plant for fall: Sep 24 to Oct 29
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Groton, MA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 4 – Feb 18 | Apr 1 – Apr 15 | — | — |
| Peppers | Feb 18 – Mar 4 | May 13 – May 27 | — | — |
| Eggplant | Feb 18 – Mar 4 | May 13 – May 27 | — | — |
| Tomatoes | Mar 4 – Mar 18 | May 6 – May 20 | — | — |
| Lettuce | Mar 4 – Mar 18 | Apr 8 – Apr 22 | Apr 1 – May 6 | Aug 13 – Sep 10 |
| Kale | Mar 4 – Mar 18 | Apr 1 – Apr 15 | Apr 1 – Apr 15 | Jul 30 – Aug 20 |
| Broccoli | Mar 4 – Mar 18 | Apr 15 – Apr 29 | — | Jul 2 – Jul 23 |
| Cabbage | Mar 4 – Mar 18 | Apr 8 – Apr 22 | — | Jul 2 – Jul 23 |
| Cauliflower | Mar 4 – Mar 18 | Apr 15 – Apr 29 | — | Jul 2 – Jul 23 |
| Okra | Mar 18 – Apr 1 | May 20 – Jun 3 | May 20 – Jun 3 | — |
| Basil | Mar 18 – Apr 1 | May 6 – May 20 | — | — |
| Peas | — | — | Mar 18 – Apr 8 | Jul 16 – Aug 6 |
| Spinach | — | — | Mar 18 – Apr 8 | Aug 13 – Sep 3 |
| Radishes | — | — | Mar 25 – May 6 | Aug 27 – Sep 17 |
| Cucumbers | Apr 1 – Apr 8 | May 13 – May 20 | May 6 – May 20 | Jul 23 – Aug 6 |
| Zucchini & Summer Squash | Apr 1 – Apr 8 | — | May 6 – May 20 | Jul 30 – Aug 13 |
| Winter Squash & Pumpkins | Apr 1 – Apr 8 | — | May 6 – May 20 | — |
| Melons & Watermelon | Apr 1 – Apr 8 | May 13 – May 27 | — | — |
| Carrots | — | — | Apr 8 – May 6 | Jul 16 – Jul 30 |
| Beets | — | — | Apr 8 – May 6 | Jul 30 – Aug 13 |
| Potatoes | — | — | Apr 8 – Apr 29 | — |
| Swiss Chard | — | — | Apr 15 – May 13 | Jul 30 – Aug 13 |
| Cilantro | — | — | Apr 15 – May 6 | Aug 13 – Sep 3 |
| Green Beans | — | — | May 6 – May 27 | Jul 23 – Aug 6 |
| Sweet Corn | — | — | May 6 – May 20 | — |
| Sweet Potatoes | — | May 13 – Jun 3 | — | — |
| Garlic | — | — | — | Sep 24 – Oct 29 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Nashua Cwsu, NH weather station, 15 km away (elevation 180 ft (55 m)).
ZIP codes in Groton: 01450 01470 01471
Frost dates near Groton
- West Groton Apr 29 · Oct 11
- Ayer Apr 29 · Oct 11
- Pepperell Apr 29 · Oct 8
- Shirley Apr 29 · Oct 11
- Dunstable Apr 29 · Oct 8
- Devens Apr 29 · Oct 11
- Littleton May 2 · Oct 6
- Westford Apr 30 · Oct 10
Frequently asked questions
When is the last frost in Groton, MA?
The median last spring frost in Groton, MA is April 29. There is still about a 10% chance of frost after May 11, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Groton, MA?
The median first fall frost is October 8, with about a 10% chance of frost before September 28.
How long is the growing season in Groton, MA?
About 162 days between the median last spring frost and first fall frost.
What planting zone is Groton, MA?
Groton, MA is in USDA hardiness zone 6a.