Frost Dates for Chelmsford, MA 01824
Last spring frost April 28 · First fall frost October 9 · 164 frost-free days · USDA Zone 6b
ZIP 01824 has about 26,700 people.
Moderate season: 164 frost-free days. Spring frost risk spans April 16–May 10 (24 days). Fall frost risk spans September 25–October 24 (29 days).
Frost probability for 01824
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 10 | April 28 | April 16 |
| Fall (first frost) | September 25 | October 9 | October 24 |
Dates come from NOAA 1971–2000 freeze probabilities at LOWELL (5.5 km away); the 50% date is the median year.
Which crops fit a 164-day season in Chelmsford
In Chelmsford (164 frost-free days, a moderate season), 31 of 56 planner crops fit outright, 24 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 24 | May 12–May 19 | 122 | fits: 80 days to maturity, 122 available after May 12. | Jun 9 |
| Pepper | Mar 17 | May 12–May 19 | 122 | fits: 75 days to maturity, 122 available after May 12. | Jun 14 |
| Lettuce | Mar 3 | Mar 31–Apr 7 | 199 | two-plantings: Plant Mar 31 and again by Aug 18; both mature before Oct 16. | Aug 18 |
| Carrots | — | Apr 7–Apr 14 | 206 | fits: 70 days to maturity, 206 available after Apr 7. | Aug 7 |
| Cucumber | Apr 7 | May 12–May 19 | 136 | two-plantings: Plant May 12 and again by Jul 13; both mature before Sep 25. | Jul 13 |
| Beans | — | May 5–May 19 | 150 | two-plantings: Plant May 5 and again by Jul 20; both mature before Oct 2. | Jul 20 |
| Peas | — | Mar 3–May 12 | 227 | fits: 65 days to maturity, 227 available after Mar 3. | Jul 29 |
| Zucchini | Apr 14 | May 12–May 19 | 136 | two-plantings: Plant May 12 and again by Jul 18; both mature before Sep 25. | Jul 18 |
| Onion | Feb 3 | Mar 31–Apr 14 | 199 | fits: 100 days to maturity, 199 available after Mar 31. | — |
| Spinach | — | Mar 3–Apr 21 | 241 | two-plantings: Plant Mar 3 and again by Sep 6; both mature before Oct 30. | Sep 6 |
| Kale | Feb 17 | Mar 31–Apr 14 | 213 | two-plantings: Plant Mar 31 and again by Aug 22; both mature before Oct 30. | Aug 22 |
| Broccoli | Mar 3 | Mar 31–Apr 14 | 199 | fits: 80 days to maturity, 199 available after Mar 31. | Jul 14 |
| Cabbage | Mar 3 | Mar 31–Apr 14 | 213 | fits: 70 days to maturity, 213 available after Mar 31. | Aug 7 |
| Radish | — | Mar 3–May 26 | 227 | two-plantings: Plant Mar 3 and again by Sep 7; both mature before Oct 16. | Sep 7 |
| Beets | — | Mar 3–May 26 | 227 | two-plantings: Plant Mar 3 and again by Aug 8; both mature before Oct 16. | Aug 8 |
| Potatoes | — | Apr 14–Apr 21 | 185 | fits: 90 days to maturity, 185 available after Apr 14. | — |
| Garlic | — | Oct 9 | 269 | overwinter: Plant Oct 9 to Oct 30; harvest the following summer. | Oct 30 |
| Strawberry | — | Mar 24–May 19 | 220 | perennial: A perennial: plant Mar 24; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 31 | May 5–May 12 | 136 | fits: 75 days to maturity, 136 available after May 5. | Jun 21 |
| Pumpkin | Apr 14 | May 12–May 12 | 129 | fits: 100 days to maturity, 129 available after May 12. | May 27 |
| Cauliflower | Mar 17 | Apr 21–May 5 | 178 | fits: 75 days to maturity, 178 available after Apr 21. | Jul 19 |
| Swiss Chard | Mar 3 | Apr 14–Apr 14 | 185 | two-plantings: Plant Apr 14 and again by Aug 8; both mature before Oct 16. | Aug 8 |
| Arugula | — | Mar 3–May 26 | 241 | two-plantings: Plant Mar 3 and again by Sep 6; both mature before Oct 30. | Sep 6 |
| Brussel Sprouts | Mar 3 | Mar 31–Apr 14 | 213 | fits: 100 days to maturity, 213 available after Mar 31. | Jul 8 |
| Butternut Squash | Apr 14 | May 12–May 19 | 129 | fits: 100 days to maturity, 129 available after May 12. | May 27 |
| Eggplant | Mar 10 | May 12–May 19 | 122 | fits: 70 days to maturity, 122 available after May 12. | Jun 19 |
| Okra | Mar 31 | May 5–May 12 | 143 | two-plantings: Plant May 5 and again by Jul 18; both mature before Sep 25. | Jul 18 |
| Basil | Mar 24 | May 19–May 19 | 129 | fits: 60 days to maturity, 129 available after May 19. | Jul 13 |
| Cilantro | — | Mar 31–Apr 21 | 199 | two-plantings: Plant Mar 31 and again by Aug 13; both mature before Oct 16. | Aug 13 |
| Parsley | Feb 17 | May 5–May 12 | 164 | fits: 70 days to maturity, 164 available after May 5. | Jul 24 |
| Celery | Feb 17 | May 5–May 19 | 164 | fits: 120 days to maturity, 164 available after May 5. | Jun 4 |
| Scallions | Feb 17 | Mar 31–Apr 14 | 213 | two-plantings: Plant Mar 31 and again by Aug 17; both mature before Oct 30. | Aug 17 |
| Turnip | — | Mar 31–Apr 14 | 213 | two-plantings: Plant Mar 31 and again by Aug 27; both mature before Oct 30. | Aug 27 |
| Kohlrabi | — | Mar 17–Mar 31 | 227 | two-plantings: Plant Mar 17 and again by Aug 22; both mature before Oct 30. | Aug 22 |
| Bok Choy | Mar 31 | Apr 21–Apr 28 | 178 | two-plantings: Plant Apr 21 and again by Aug 18; both mature before Oct 16. | Aug 18 |
| Collards | Feb 17 | Mar 31–Apr 14 | 213 | two-plantings: Plant Mar 31 and again by Aug 17; both mature before Oct 30. | Aug 17 |
| Cantaloupe | Apr 14 | May 12–May 19 | 122 | fits: 85 days to maturity, 122 available after May 12. | Jun 4 |
| Chives | Feb 3 | May 5–May 12 | 178 | fits: 90 days to maturity, 178 available after May 5. | — |
| Dill | — | Mar 3–May 26 | 227 | two-plantings: Plant Mar 3 and again by Aug 8; both mature before Oct 16. | Aug 8 |
| Oregano | Feb 17 | May 5–May 12 | 178 | fits: 80 days to maturity, 178 available after May 5. | — |
| Rosemary | Feb 3 | May 5–May 12 | 164 | fits: 80 days to maturity, 164 available after May 5. | — |
| Sage | Mar 3 | May 5–May 12 | 178 | fits: 75 days to maturity, 178 available after May 5. | — |
| Thyme | Feb 17 | May 5–May 12 | 178 | fits: 90 days to maturity, 178 available after May 5. | — |
| Calendula | Mar 17 | Apr 14–Apr 28 | 185 | two-plantings: Plant Apr 14 and again by Aug 13; both mature before Oct 16. | Aug 13 |
| Cosmos | Mar 31 | Apr 28–May 12 | 150 | two-plantings: Plant Apr 28 and again by Jul 13; both mature before Sep 25. | Jul 13 |
| Lavender | Feb 3 | Apr 28–May 12 | 185 | fits: 90 days to maturity, 185 available after Apr 28. | — |
| Marigolds | Mar 17 | Apr 28–May 5 | 150 | two-plantings: Plant Apr 28 and again by Jul 23; both mature before Sep 25. | Jul 23 |
| Melons | Apr 14 | May 12–May 19 | 122 | fits: 85 days to maturity, 122 available after May 12. | Jun 4 |
| Mint | — | Apr 28–May 12 | 185 | fits: 90 days to maturity, 185 available after Apr 28. | — |
| Nasturtiums | Mar 31 | Apr 28–May 5 | 150 | two-plantings: Plant Apr 28 and again by Jul 18; both mature before Sep 25. | Jul 18 |
| Pole Beans | — | May 5–May 19 | 143 | fits: 65 days to maturity, 143 available after May 5. | Jul 8 |
| Spaghetti Squash | Apr 14 | May 12–May 19 | 129 | fits: 90 days to maturity, 129 available after May 12. | Jun 6 |
| Sunflowers | — | Apr 28–May 12 | 150 | fits: 70 days to maturity, 150 available after Apr 28. | Jul 3 |
| Tomatillos | Mar 3 | May 5–May 12 | 129 | fits: 75 days to maturity, 129 available after May 5. | Jun 14 |
| Watermelon | Apr 14 | May 5–May 12 | 129 | fits: 80 days to maturity, 129 available after May 5. | Jun 9 |
| Yellow Squash | Apr 14 | May 12–May 19 | 136 | two-plantings: Plant May 12 and again by Jul 18; both mature before Sep 25. | Jul 18 |
| Zinnias | Mar 31 | Apr 28–May 12 | 150 | two-plantings: Plant Apr 28 and again by Jul 13; both mature before Sep 25. | Jul 13 |
Month by month in Chelmsford
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 3), Lavender (Feb 3), Onion (Feb 3), Rosemary (Feb 3), Celery (Feb 17), Collards (Feb 17), +5 more. |
| March | Start indoors: Broccoli (Mar 3), Brussel Sprouts (Mar 3), Cabbage (Mar 3), Lettuce (Mar 3), Sage (Mar 3), Swiss Chard (Mar 3), +14 more. Direct sow from: Arugula (Mar 3), Beets (Mar 3), Dill (Mar 3), Peas (Mar 3), Radish (Mar 3), Spinach (Mar 3), +3 more. Transplant from: Broccoli (Mar 31), Brussel Sprouts (Mar 31), Cabbage (Mar 31), Collards (Mar 31), Kale (Mar 31), Lettuce (Mar 31), +2 more. Plant: Strawberry (Mar 24). |
| April | Start indoors: Cucumber (Apr 7), Butternut Squash (Apr 14), Cantaloupe (Apr 14), Melons (Apr 14), Pumpkin (Apr 14), Spaghetti Squash (Apr 14), +3 more. Direct sow from: Carrots (Apr 7), Potatoes (Apr 14), Sunflowers (Apr 28). Transplant from: Calendula (Apr 14), Swiss Chard (Apr 14), Bok Choy (Apr 21), Cauliflower (Apr 21), Cosmos (Apr 28), Lavender (Apr 28), +4 more. Last frost around April 28. |
| May | Direct sow from: Beans (May 5), Pole Beans (May 5). Transplant from: Celery (May 5), Chives (May 5), Corn (May 5), Okra (May 5), Oregano (May 5), Parsley (May 5), +17 more. Last sowing dates: Butternut Squash (May 27), Pumpkin (May 27). |
| June | Last sowing dates: Cantaloupe (Jun 4), Celery (Jun 4), Melons (Jun 4), Spaghetti Squash (Jun 6), Tomato (Jun 9), Watermelon (Jun 9), +4 more. |
| July | Last sowing dates: Sunflowers (Jul 3), Brussel Sprouts (Jul 8), Pole Beans (Jul 8), Basil (Jul 13), Cosmos (Jul 13), Cucumber (Jul 13), +11 more. |
| August | Last sowing dates: Cabbage (Aug 7), Carrots (Aug 7), Beets (Aug 8), Dill (Aug 8), Swiss Chard (Aug 8), Calendula (Aug 13), +8 more. |
| September | Last sowing dates: Arugula (Sep 6), Spinach (Sep 6), Radish (Sep 7). |
| October | Direct sow from: Garlic (Oct 9). First frost around October 9. Last sowing dates: Garlic (Oct 30). |
| November | Harvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year. |
| December | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
Frequently Asked Questions
What is the last frost date for Chelmsford, MA (ZIP 01824)?
The median last spring frost date for Chelmsford, MA (ZIP code 01824) is around April 28. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before April 16; one in ten it runs past May 10.
What is the first fall frost date in Chelmsford, MA?
The median first fall frost date for Chelmsford, MA is around October 9. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around September 25 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Chelmsford, MA?
The frost-free growing season in Chelmsford is about 164 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Chelmsford (164 frost-free days, a moderate season), 31 of 56 planner crops fit outright, 24 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Chelmsford, MA?
Chelmsford, MA is in USDA hardiness zone 6b (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Chelmsford, MA?
Start tomatoes indoors Mar 24 and plant out May 12 in Chelmsford. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Chelmsford?
Two: plant Mar 31 and again by Aug 18; both mature before Oct 16.
When do I plant garlic in Chelmsford?
Oct 9 to Oct 30; it overwinters and is ready the following summer.
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