USDA zone 5b in Massachusetts
USDA plant hardiness zone 5b covers 11 locations across Massachusetts (average annual extreme minimum −15 to −10 °F): Amherst, MA, Gardner, MA, Gardner, MA, Great Barrington, MA, Greenfield, MA, North Adams, MA, and 5 more. Average last spring frost across this group ranges April 29 (Gardner) to May 17 (Shelburne Falls), and growing seasons run 136–164 days (Shelburne Falls to Gardner) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Massachusetts location's own frost dates; the printable planting calendar uses Gardner, this group's median-season location.
- USDA zone
- 5b−15 to −10 °F
- Last frost range
- Apr 29–May 17avg, 32°F
- First frost range
- Oct 1–Oct 11avg, 32°F
- Growing season range
- 136–164days
Locations in this group
Every location below shares this zone and a nearby weather station, but keeps its own frost dates — find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.
| Location | Also covers | Nearest station | Last frost | First frost | Season (days) |
|---|---|---|---|---|---|
| Amherst | — | Amherst | May 5 | Oct 8 | 156 |
| Gardner * | Baldwinville, Winchendon | Birch Hill Dam | May 6 | Oct 1 | 148 |
| Gardner | — | Fitchburg Muni Ap | Apr 29 | Oct 11 | 164 |
| Great Barrington | Chester, Lee, Chatham, Blandford, Housatonic, Lenox Dale | Lenox Dale | May 7 | Oct 3 | 147 |
| Greenfield | Athol, Orange, Northfield, Baldwinville, Petersham, Millers Falls | Orange Muni Ap | May 4 | Oct 8 | 157 |
| North Adams | Stamford, Williamstown, Adams, Readsboro, North Pownal, Pownal, +1 more | North Adams Harriman Ap | May 10 | Oct 4 | 147 |
| Pittsfield | Shelburne Falls, Cheshire | Worthington | May 13 | Oct 2 | 144 |
| Pittsfield | East Nassau, Lenox, Chatham, Cheshire | Pittsfield Muni Ap | May 5 | Oct 5 | 152 |
| Shelburne Falls | — | E Hawley | May 17 | Oct 1 | 136 |
| Shelburne Falls | — | Greenfield #3 | May 1 | Oct 11 | 162 |
| Shelburne Falls | Jacksonville, Whitingham | Rowe 3ne | May 14 | Oct 4 | 143 |
* Gardner is this group's median-season location — the calendar below is computed from its data.
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Planting calendar (Gardner, representative)
Computed from Gardner's average frost dates — the median-season location in this Massachusettszone 5b group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting | Season fit |
|---|---|---|---|---|---|---|
| Tomato | Tender | Mar 11 – Mar 25 | May 13 – May 20 | Jul 12 – Aug 1 | — | matures comfortably |
| Pepper | Very tender | Feb 25 – Mar 11 | May 20 – May 27 | Jul 19 – Aug 18 | — | matures comfortably |
| Cucumber | Tender | Apr 8 – Apr 15 | May 13 – May 20 | Jul 2 – Jul 22 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | May 13 – May 20 | Jun 27 – Jul 12 | — | matures comfortably |
| Bush bean | Tender | — | May 13 – May 20 | Jul 2 – Jul 12 | Aug 2 – Aug 12 | matures comfortably |
| Sweet corn | Tender | — | May 6 – May 20 | Jul 5 – Aug 4 | — | matures comfortably |
| Basil | Very tender | Mar 25 – Apr 8 | May 13 – May 20 | Jun 12 – Jun 27 | — | matures comfortably |
| Lettuce | Half-hardy | Mar 25 – Apr 8 | Apr 8 – Apr 22 | May 23 – Jun 7 | Jul 19 – Aug 3 | matures comfortably |
| Pea | Hardy | — | Mar 25 – Apr 8 | May 19 – Jun 3 | Jul 9 – Jul 24 | matures comfortably |
| Spinach | Hardy | — | Mar 25 – Apr 8 | May 4 – May 14 | Jul 29 – Aug 8 | matures comfortably |
| Carrot | Half-hardy | — | Apr 15 – Apr 22 | Jun 14 – Jul 4 | Jun 29 – Jul 19 | matures comfortably |
| Broccoli | Half-hardy | Mar 11 – Mar 25 | Apr 8 – Apr 22 | Jun 2 – Jun 22 | Jul 4 – Jul 24 | matures comfortably |
Which crops fit this growing season
Using Gardner's own 148-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.
Frost & freeze dates (Gardner)
From NOAA's 1991–2020 Climate Normals at station USC00190666. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | May 19 | Jun 3 | Sep 23 | Oct 4 | 126 |
| 32°F (freeze) | May 6 | May 19 | Oct 1 | Oct 16 | 148 |
| 28°F | Apr 23 | May 5 | Oct 12 | Oct 31 | 172 |
| 24°F | Apr 9 | Apr 22 | Oct 25 | Nov 11 | 198 |
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 11 locations is 2,282; Gardner's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 2,282 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 4,203 | cool-season crops (brassicas, greens) |
Hardiness zone 5b in Massachusetts
Zone 5b means an average annual extreme minimum winter temperature of about −15 to −10 °F on the USDA's 2023 map — the number that tells you which perennials, shrubs, and trees reliably survive an average winter here. It does not set your planting dates, which come from the frost calendar above. Massachusetts spans 5 hardiness zones in this dataset — see all Massachusetts locations for the full range, including zones6a, 6b, 7a, 7b.
Explore zone 5b in other states at zone 5b, or see all USDA hardiness zones.
Frequently asked questions
- What does USDA hardiness zone 5b mean in Massachusetts?
- Zone 5b means an average annual extreme minimum winter temperature of −15 to −10 °F — the standard USDA measure of which perennials survive winter. 11 locations in Massachusetts fall in this zone. It does not set planting dates; see the frost calendar below for that.
- Where in Massachusetts's zone 5b is the growing season longest?
- Gardner runs the longest season on this page at about 164 days; Shelburne Falls is shortest at about 136 days — they share the same hardiness zone, but they sit at different weather stations, so their frost calendars differ.
- When should I plant tomatoes in Massachusetts's zone 5b?
- Using Gardner's frost dates (this page's median-season location): start seeds indoors about Mar 11 – Mar 25, then transplant outside about May 13 – May 20. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
- Does every location in Massachusetts's zone 5b have the same frost dates?
- No — they do not all share a weather station, so frost dates vary by a week or more across the 11 locations listed (see the table above for each location's own dates).
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.