Johnston, RI planting zone & frost dates
Johnston is in USDA hardiness zone 6b. The last spring frost usually comes around April 11 and the first fall frost around October 30, for a growing season of about 199 days.
Planting calendar for Johnston
Dates are counted from the average last spring frost (April 11) 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 14 – Feb 28 Transplant outdoors: Apr 18 – Apr 25 |
| Peppers | Start seeds indoors: Jan 31 – Feb 14 Transplant outdoors: Apr 25 – May 2 |
| Eggplant | Start seeds indoors: Jan 31 – Feb 14 Transplant outdoors: Apr 25 – May 2 |
| Broccoli | Start seeds indoors: Jan 31 – Feb 14 Transplant outdoors: Mar 14 – Mar 28 |
| Cabbage | Start seeds indoors: Jan 31 – Feb 14 Transplant outdoors: Mar 14 – Mar 28 |
| Onions (sets) | Plant outdoors: Mar 14 – Mar 28 |
| Peas | Sow outdoors: Feb 28 – Mar 14 |
| Spinach | Sow outdoors: Feb 28 – Mar 14 |
| Lettuce | Sow outdoors: Mar 14 – Mar 28 |
| Carrots | Sow outdoors: Mar 14 – Mar 28 |
| Potatoes | Plant outdoors: Mar 14 – Mar 28 |
| Beans | Sow outdoors: Apr 18 – Apr 25 |
| Sweet corn | Sow outdoors: Apr 18 – Apr 25 |
| Cucumbers | Sow outdoors: Apr 18 – Apr 25 |
| Squash & zucchini | Sow outdoors: Apr 18 – Apr 25 |
| Basil | Start seeds indoors: Feb 28 – Mar 14 Transplant outdoors: Apr 18 – Apr 25 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Sep 4 (8 weeks before the average first fall frost on Oct 30).
Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Apr 1 | Apr 11 | Apr 23 |
| First 32°F frost in fall is before | Nov 12 | Oct 30 | Oct 16 |
How to read it: in spring there is a 10% chance of a frost after April 23, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 16. A hard freeze (28°F) usually ends around April 1.
Hardiness zone by ZIP code in Johnston
- 02919 zone 6b
Nearby cities
- North Providence zone 6b, last frost Apr 11
- North Scituate zone 6b, last frost Apr 25
- Cranston zone 7a, last frost Apr 11
- Providence zone 7a, last frost Apr 11
- Smithfield zone 6b, last frost Apr 22
- Lincoln zone 6b, last frost Apr 22
- West Warwick zone 6b, last frost Apr 22
- Central Falls zone 7a, last frost Apr 22
Questions
What growing zone is Johnston, RI?
Johnston 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 Johnston?
The average last spring frost (32°F) in Johnston is April 11. There is still a 10% chance of frost until April 23.
When can I plant tomatoes in Johnston?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 18 – Apr 25. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Providence T F Green Ap, RI (USW00014765), 12.7 km (7.9 mi) from the city center, elevation 18 m, based on 30 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.