Gardening in Boston-Cambridge-Newton, MA-NH
This metro spans USDA zones 5b to 7a, so there is no single zone for Boston-Cambridge-Newton, MA-NH and anyone who gives you one is rounding. 55% of its ZIP codes are zone 6b; the rest are not.
Which zone you are in depends where you are
Boston-Cambridge-Newton, MA-NH covers 4 hardiness zones. A guide that gives the metro one zone has picked whichever is largest and rounded everyone else into it — which is fine for the 55% in zone 6b and wrong for the other 45%. Here is the actual split.
| Zone | ZIP codes | Share | |
|---|---|---|---|
| 6b | 158 | 55% | |
| 6a | 64 | 22% | |
| 7a | 59 | 21% | |
| 5b | 4 | 1% |
Zones are published per ZIP code, so yours is exact even though the metro's is not. The hardiness tool will tell you which one you are in.
Your freeze dates
Those are the earliest and latest medians among the 47 stations serving this metro — not an average, and not one station standing in for the rest. Half of years freeze later than a station's own median.
The spread is the point. Even in a metro that is one hardiness zone throughout, its stations disagree about the last spring freeze. Hardiness zone and frost date measure different things — a zone is the average annual coldest night, a freeze date is when the season turns — and a place can be uniform in one and varied in the other. Use the tools below with your own ZIP rather than the ends of this range.
Your growing season
NOAA publishes a growing-season length for each station, and across the 47 stations serving Boston-Cambridge-Newton, MA-NH it runs 136–218 days . That figure is published, not computed from the two freeze dates — subtracting one from the other gives the wrong answer wherever a season crosses New Year. Mean summer high (June–August) runs 78–84 °F , below the 90 °F point where cool-season crops reliably bolt.
When to start seeds in Boston-Cambridge-Newton, MA-NH
Every spring job for 63 crop dates, counted from this metro's own last spring freeze. Each is a range across all 47 stations — the earliest and latest that job falls anywhere in the metro — because no one station speaks for the whole area.
| Crop | Job | When | Offset |
|---|---|---|---|
| Green Onions | Start indoors | February 7 – March 21 | 8 weeks before |
| Peppers | Start indoors | February 7 – March 21 | 8 weeks before |
| Broccoli | Start indoors | February 21 – April 4 | 6 weeks before |
| Cabbage | Start indoors | February 21 – April 4 | 6 weeks before |
| Collards | Start indoors | February 21 – April 4 | 6 weeks before |
| Kale | Start indoors | February 21 – April 4 | 6 weeks before |
| Leaf Lettuce | Start indoors | February 21 – April 4 | 6 weeks before |
| Peas | Direct sow | February 21 – April 4 | 6 weeks before |
| Spinach | Direct sow | February 21 – April 4 | 6 weeks before |
| Sweet Potato | Start indoors | February 21 – April 4 | 6 weeks before |
| Tomatoes | Start indoors | February 21 – April 4 | 6 weeks before |
| Bok Choy | Start indoors | February 28 – April 11 | 5 weeks before |
| Kohlrabi | Start indoors | February 28 – April 11 | 5 weeks before |
| Swiss Chard | Start indoors | February 28 – April 11 | 5 weeks before |
| Arugula | Direct sow | March 7 – April 18 | 4 weeks before |
| Baby Salad Greens | Direct sow | March 7 – April 18 | 4 weeks before |
| Beets | Direct sow | March 7 – April 18 | 4 weeks before |
| Green Onions | Direct sow | March 7 – April 18 | 4 weeks before |
| Mustard Greens | Direct sow | March 7 – April 18 | 4 weeks before |
| Okra | Start indoors | March 7 – April 18 | 4 weeks before |
| Radishes | Direct sow | March 7 – April 18 | 4 weeks before |
| Turnips | Direct sow | March 7 – April 18 | 4 weeks before |
| Cabbage | Set out | March 14 – April 25 | 3 weeks before |
| Carrots | Direct sow | March 14 – April 25 | 3 weeks before |
| Collards | Direct sow | March 14 – April 25 | 3 weeks before |
| Collards | Set out | March 14 – April 25 | 3 weeks before |
| Cucumbers | Start indoors | March 14 – April 25 | 3 weeks before |
| Green Onions | Set out | March 14 – April 25 | 3 weeks before |
| Kale | Direct sow | March 14 – April 25 | 3 weeks before |
| Kale | Set out | March 14 – April 25 | 3 weeks before |
| Kohlrabi | Direct sow | March 14 – April 25 | 3 weeks before |
| Kohlrabi | Set out | March 14 – April 25 | 3 weeks before |
| Leaf Lettuce | Direct sow | March 14 – April 25 | 3 weeks before |
| Pumpkins | Start indoors | March 14 – April 25 | 3 weeks before |
| Summer Squash | Start indoors | March 14 – April 25 | 3 weeks before |
| Winter Squash | Start indoors | March 14 – April 25 | 3 weeks before |
| Zucchini | Start indoors | March 14 – April 25 | 3 weeks before |
| Bok Choy | Direct sow | March 21 – May 2 | 2 weeks before |
| Bok Choy | Set out | March 21 – May 2 | 2 weeks before |
| Broccoli | Set out | March 21 – May 2 | 2 weeks before |
| Cilantro | Direct sow | March 21 – May 2 | 2 weeks before |
| Leaf Lettuce | Set out | March 21 – May 2 | 2 weeks before |
| Swiss Chard | Direct sow | March 21 – May 2 | 2 weeks before |
| Swiss Chard | Set out | March 21 – May 2 | 2 weeks before |
| Dill | Direct sow | March 28 – May 9 | 1 week before |
| Bush Beans | Direct sow | April 11 – May 23 | 1 week after |
| Cucumbers | Set out | April 11 – May 23 | 1 week after |
| Pumpkins | Direct sow | April 11 – May 23 | 1 week after |
| Pumpkins | Set out | April 11 – May 23 | 1 week after |
| Summer Squash | Direct sow | April 11 – May 23 | 1 week after |
| Summer Squash | Set out | April 11 – May 23 | 1 week after |
| Sweet Corn | Direct sow | April 11 – May 23 | 1 week after |
| Tomatoes | Set out | April 11 – May 23 | 1 week after |
| Winter Squash | Direct sow | April 11 – May 23 | 1 week after |
| Winter Squash | Set out | April 11 – May 23 | 1 week after |
| Zucchini | Direct sow | April 11 – May 23 | 1 week after |
| Zucchini | Set out | April 11 – May 23 | 1 week after |
| Cucumbers | Direct sow | April 18 – May 30 | 2 weeks after |
| Okra | Direct sow | April 18 – May 30 | 2 weeks after |
| Okra | Set out | April 18 – May 30 | 2 weeks after |
| Peppers | Set out | April 18 – May 30 | 2 weeks after |
| Southern Peas | Direct sow | April 18 – May 30 | 2 weeks after |
| Sweet Potato | Set out | April 18 – May 30 | 2 weeks after |
The week offsets are conventional extension guidance and vary by variety; the freeze dates they are counted from are measured. For a single date rather than a range, run when do I start my seeds? with your own ZIP code.
What survives the winter changes across Boston-Cambridge-Newton, MA-NH
Of 74 perennial fruits, nuts, berries, vegetables and herbs, 58 come through the winter in zone 7a and only 48 in zone 5b. That is a different garden at each end of the same metro.
| Zone | ZIPs | Survive | Fail for being too warm |
|---|---|---|---|
| 5b | 4 | 48 of 74 | 0 |
| 6a | 64 | 51 of 74 | 0 |
| 6b | 158 | 51 of 74 | 0 |
| 7a | 59 | 58 of 74 | 1 |
The last column is the counterintuitive one, and it is why the totals do not simply rise as the winters get milder. Most temperate fruit needs a documented number of hours below about 45 °F to break dormancy and set a crop, so an apple fails in a winter that is too warm; currants and rhubarb cook in the summer heat that comes with it. See the full list with reasons.
The 47 stations behind these numbers
Every figure above comes from these, and each is named so you can check it. Distances vary by ZIP code, so the tools report yours rather than this page guessing.
| Station | NOAA ID | Last spring freeze | First fall freeze | Season |
|---|---|---|---|---|
| Bedford Hanscom FLD, MA | USW00014702 | April 28 | October 10 | 165 days |
| Bedford, MA | USC00190535 | April 27 | October 13 | 169 days |
| Beverly Muni AP, MA | USW00054733 | April 24 | October 17 | 177 days |
| Beverly, MA | USC00190593 | May 4 | October 12 | 160 days |
| Blue Hill Coop, MA | USC00190736 | April 18 | October 26 | 190 days |
| Boston Logan INTL AP, MA | USW00014739 | April 4 | November 9 | 218 days |
| Bridgewater, MA | USC00190840 | May 1 | October 9 | 161 days |
| Brockton, MA | USC00190860 | April 22 | October 19 | 178 days |
| Concord Muni AP, NH | USW00014745 | May 8 | October 3 | 146 days |
| Durham 2 N, NH | USW00054794 | May 3 | October 10 | 158 days |
| Durham 2 Ssw, NH | USW00054795 | May 7 | October 4 | 150 days |
| Durham, NH | USC00272174 | May 8 | October 4 | 148 days |
| E Wareham, MA | USC00192451 | April 21 | October 24 | 186 days |
| Epping, NH | USC00272800 | May 7 | October 4 | 148 days |
| Fitchburg Coop, MA | USC00192807 | May 1 | October 9 | 162 days |
| Fitchburg Muni AP, MA | USW00004780 | April 29 | October 11 | 164 days |
| Greenland, NH | USC00273626 | May 4 | October 8 | 157 days |
| Groveland, MA | USC00193276 | May 3 | October 8 | 158 days |
| Haverhill, MA | USC00193505 | May 1 | October 12 | 163 days |
| Hingham, MA | USC00193624 | April 25 | October 22 | 177 days |
| Hudson 1 Sse, NH | USC00274234 | May 3 | October 8 | 156 days |
| Jamaica Plain, MA | USC00193890 | April 19 | October 23 | 185 days |
| Lakeport 2, NH | USC00274480 | April 30 | October 18 | 170 days |
| Lawrence Muni AP, MA | USW00094723 | April 21 | October 21 | 182 days |
| Lawrence, MA | USC00194105 | April 13 | October 28 | 198 days |
| Lowell, MA | USC00194313 | April 30 | October 10 | 164 days |
| Manchester AP, NH | USW00014710 | April 21 | October 19 | 180 days |
| Marblehead, MA | USC00194502 | April 25 | October 20 | 176 days |
| Massabesic Lake, NH | USC00275211 | April 30 | October 11 | 164 days |
| Maynard 2, MA | USC00194580 | May 2 | October 6 | 156 days |
| Middleboro, MA | USC00194711 | April 23 | October 16 | 174 days |
| Middleton, MA | USC00194744 | May 3 | October 9 | 157 days |
| Nashua Cwsu, NH | USC00275703 | April 29 | October 8 | 162 days |
| Natick, MA | USC00195175 | April 26 | October 12 | 169 days |
| New Bedford Coop, MA | USC00195246 | April 11 | November 5 | 208 days |
| Norton W, MA | USC00195984 | April 27 | October 15 | 168 days |
| Norwood Mem AP, MA | USW00054704 | April 25 | October 9 | 167 days |
| Plymouth Muni AP, MA | USW00054769 | April 30 | October 16 | 170 days |
| Plymouth-Kingston, MA | USC00196486 | April 15 | November 1 | 198 days |
| Reading, MA | USC00196783 | April 25 | October 17 | 174 days |
| Rochester Skyhaven AP, NH | USW00054791 | April 30 | October 9 | 161 days |
| Rochester, MA | USC00196938 | April 23 | October 21 | 180 days |
| Sanford 2 Nnw, ME | USC00177479 | May 16 | September 30 | 136 days |
| W Hampstead, NH | USC00279278 | April 30 | October 11 | 162 days |
| Walpole 2, MA | USC00198757 | April 27 | October 14 | 169 days |
| West Medway, MA | USC00199316 | April 30 | October 9 | 162 days |
| Woonsocket, RI | USC00379423 | April 22 | October 19 | 179 days |
These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.
Work out your own dates
Each of these takes a ZIP code and answers for that ZIP alone, citing the station it used and how far away it is. There is a ZIP box in the header of every page.
- What survives my winter?
Runs on the hardiness zone, so it answers for all of Boston-Cambridge-Newton, MA-NH at once — zone across 74 perennial fruits, berries, vegetables and herbs.
- When do I start my seeds?
Dates every spring job from your own last freeze — sow indoors, set out, direct sow.
- When do I sow the next round?
How often each crop is worth re-sowing, and when the next sowing is due.
- What can I still plant?
Counts the growing days left before your first fall freeze, crop by crop.
Where these numbers come from
The hardiness zone is the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. The freeze dates are NOAA's 1991–2020 Climate Normals, read from every station whose normals cover a ZIP code in this metro. Nothing here is estimated, and no station stands in for another.
This page names no single station on purpose. Picking one to represent a metro sounds reasonable and is not: the station serving the most ZIP codes is an artifact of where ZIP centroids happen to fall, and it selects a lock on the Monongahela for Pittsburgh and a far southern suburb for Chicago. A range across every station is true; a single cited date for a whole metro is not.