Hartford, CT planting zone & frost dates
Hartford is in USDA hardiness zone 6b. The last spring frost usually comes around April 17 and the first fall frost around October 26, for a growing season of about 191 days.
Planting calendar for Hartford
Dates are counted from the average last spring frost (April 17) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Feb 20 – Mar 6 Transplant outdoors: Apr 24 – May 1 |
| Peppers | Start seeds indoors: Feb 6 – Feb 20 Transplant outdoors: May 1 – May 8 |
| Eggplant | Start seeds indoors: Feb 6 – Feb 20 Transplant outdoors: May 1 – May 8 |
| Broccoli | Start seeds indoors: Feb 6 – Feb 20 Transplant outdoors: Mar 20 – Apr 3 |
| Cabbage | Start seeds indoors: Feb 6 – Feb 20 Transplant outdoors: Mar 20 – Apr 3 |
| Onions (sets) | Plant outdoors: Mar 20 – Apr 3 |
| Peas | Sow outdoors: Mar 6 – Mar 20 |
| Spinach | Sow outdoors: Mar 6 – Mar 20 |
| Lettuce | Sow outdoors: Mar 20 – Apr 3 |
| Carrots | Sow outdoors: Mar 20 – Apr 3 |
| Potatoes | Plant outdoors: Mar 20 – Apr 3 |
| Beans | Sow outdoors: Apr 24 – May 1 |
| Sweet corn | Sow outdoors: Apr 24 – May 1 |
| Cucumbers | Sow outdoors: Apr 24 – May 1 |
| Squash & zucchini | Sow outdoors: Apr 24 – May 1 |
| Basil | Start seeds indoors: Mar 6 – Mar 20 Transplant outdoors: Apr 24 – May 1 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 31 (8 weeks before the average first fall frost on Oct 26).
Useful for zone 6b gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Cold frame / mini greenhouse — adds weeks to a short season
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Apr 1 | Apr 17 | May 1 |
| First 32°F frost in fall is before | Nov 7 | Oct 26 | Oct 12 |
How to read it: in spring there is a 10% chance of a frost after May 1, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 12. A hard freeze (28°F) usually ends around April 3.
Hardiness zone by ZIP code in Hartford
- 06101 zone 6b
- 06102 zone 6b
- 06103 zone 6b
- 06104 zone 6b
- 06105 zone 6b
- 06106 zone 6b
- 06112 zone 6b
- 06114 zone 6b
- 06115 zone 6b
- 06120 zone 6b
- 06123 zone 6b
- 06126 zone 6b
- 06132 zone 6b
- 06134 zone 6b
- 06140 zone 6b
- 06141 zone 6b
- 06142 zone 6b
- 06143 zone 6b
- 06144 zone 6b
- 06145 zone 6b
- 06146 zone 6b
- 06147 zone 6b
- 06150 zone 6b
- 06151 zone 6b
- 06152 zone 6b
- 06153 zone 6b
- 06154 zone 6b
- 06155 zone 6b
- 06156 zone 6b
- 06160 zone 6b
- 06161 zone 6b
- 06167 zone 6b
- 06176 zone 6b
- 06180 zone 6b
- 06183 zone 6b
- 06199 zone 6b
Nearby cities
- West Hartford zone 6b, last frost Apr 17
- Wethersfield zone 6b, last frost Apr 17
- East Hartford zone 6b, last frost Apr 17
- Newington zone 6b, last frost Apr 17
- Bloomfield zone 6b, last frost Apr 17
- South Windsor zone 6b, last frost Apr 17
- Glastonbury zone 6b, last frost Apr 17
- Windsor zone 6b, last frost Apr 21
Questions
What growing zone is Hartford, CT?
Hartford is in USDA Plant Hardiness Zone 6b (average extreme winter low -5°F to 0°F), according to the USDA 2023 map.
When is the last frost in Hartford?
The average last spring frost (32°F) in Hartford is April 17. There is still a 10% chance of frost until May 1.
When can I plant tomatoes in Hartford?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 24 – May 1. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Hartford Brainard Fld, CT (USW00014752), 4.2 km (2.6 mi) from the city center, elevation 6 m, based on 28 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.