Lowell, Massachusetts: planting zone & frost dates
Lowell is in USDA plant hardiness zone 6b, where the average coldest winter night reaches -5 to 0°F (-20.6 to -17.8°C). The typical last spring frost is around May 3 and the first fall frost around Oct 5.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 10 | Sep 30 |
| Typical planning date (30% risk) | May 3 | Oct 5 |
| Median (50%) | Apr 30 | Oct 10 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station LOWELL, MA (USC00194313), 2.2 mi (3.5 km) from the city center and 16 ft higher than the city center (+5 m). Record used for the 1991–2020 normals: 28 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Lowell
All 4 ZIP codes covering Lowell are in zone 6b.
Vegetable planting calendar for Lowell
Dates are counted from the 30%-risk frost dates above (last frost May 3, first frost Oct 5). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Mar 8 – Mar 22 | May 10 – May 24 | — | — |
| Pepper | Feb 22 – Mar 8 | May 17 – May 31 | — | — |
| Lettuce | Mar 22 – Apr 5 | Apr 19 – May 10 | Apr 5 – May 17 | Jul 27 – Aug 24 |
| Green Beans | — | — | May 10 – Jun 14 | Jul 13 – Jul 27 |
| Sweet Corn | — | — | May 10 – Jun 7 | — |
| Zucchini & Summer Squash | Apr 5 – Apr 12 | May 10 – May 24 | May 10 – May 31 | Jul 13 – Jul 27 |
| Cucumber | Apr 5 – Apr 12 | May 17 – May 24 | May 10 – May 31 | Jul 13 – Jul 27 |
| Carrot | — | — | Apr 12 – May 17 | Jul 13 – Jul 27 |
| Onion | Feb 8 – Feb 22 | Apr 5 – Apr 19 | — | — |
| Potato | — | Apr 5 – Apr 26 | — | — |
| Basil | Mar 22 – Apr 5 | May 17 – May 31 | May 17 – Jun 7 | — |
| Spinach | — | — | Mar 22 – Apr 19 | Aug 10 – Sep 7 |
| Kale | Mar 8 – Mar 22 | Apr 5 – Apr 26 | Apr 5 – Apr 26 | Jul 27 – Aug 24 |
| Broccoli | Mar 8 – Mar 22 | Apr 19 – May 10 | — | Jul 13 – Jul 27 |
| Peas | — | — | Mar 22 – Apr 12 | Jul 27 – Aug 10 |
| Eggplant | Feb 22 – Mar 8 | May 17 – May 31 | — | — |
| Cabbage | Mar 8 – Mar 22 | Apr 5 – Apr 19 | — | Jul 13 – Jul 27 |
| Radish | — | — | Mar 29 – May 17 | Aug 24 – Sep 21 |
| Strawberry | — | Apr 5 – Apr 26 | — | — |
| Beets | — | — | Apr 12 – May 24 | Jul 27 – Aug 10 |
Nearby cities in Massachusetts
- Lawrence — zone 6b, last frost Apr 19, first frost Oct 22
- Newton — zone 6b, last frost Apr 24, first frost Oct 16
- Cambridge — zone 6b, last frost Apr 8, first frost Nov 3
- Somerville — zone 7a, last frost Apr 8, first frost Nov 3
- Lynn — zone 7a, last frost May 1, first frost Oct 14
- Boston — zone 6b, last frost Apr 8, first frost Nov 3
More: all Massachusetts cities · other zone 6b cities: Columbus, OH, Indianapolis, IN, Boston, MA, Detroit, MI, Kansas City, MO, Cincinnati, OH, Pittsburgh, PA, Buffalo, NY
Lowell gardening questions
When is the last frost in Lowell, MA?
Plan around May 3. At NOAA's Lowell, MA station, 2.2 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Apr 30, and after May 10 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 18. The last frost is fairly predictable here: only 21 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Lowell, MA?
Start seeds indoors Mar 8 – Mar 22 and set transplants outside May 10 – May 24, once nights stay above 50°F and the soil is near 60°F. That leaves 155 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Lowell?
About 164 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 148 days, and in 1 year in 10 it runs 179 days or more. In fall there is a 10% chance of frost by Sep 30 and a 30% chance by Oct 5. That ranks 11th longest of 13 Massachusetts cities on this site.
When should I plant a fall garden in Lowell?
Count back from the first fall frost (Oct 5): transplant broccoli Jul 13 – Jul 27; sow kale Jul 27 – Aug 24; sow lettuce Jul 27 – Aug 24; sow radishes Aug 24 – Sep 21. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Oct 22. How the math works: succession and fall planting.
Did Lowell's hardiness zone change on the 2023 map?
Yes. Most of Lowell was zone 6a on the 2012 map and is zone 6b on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
How does Lowell compare with Lawrence, MA?
Both are in zone 6b. The typical last spring frost in Lowell (May 3) comes about 14 days later than in Lawrence, MA (Apr 19), 9 miles away, and the first fall frost is Oct 5 versus Oct 22. The two cities use different NOAA stations.