Kale
What Plant Yet? knows about kale, and where each number comes from. For today's answer, pick your town.
Planting numbers
- Frost category
- Hardy Source: Utah State University Extension
- Plant outdoors
- 4 weeks before typical last frost Source: Colorado State University Extension
- Start seeds indoors
- 5–6 weeks before planting out Source: Utah State University Extension
- Cover at or below
- 25°F Source: Utah State University Extension
- Days to harvest
- 55–75 Source: Iowa State University Extension
Left out because we found no university extension source for it: minimum night temperature. We don't estimate.
Growing tips
- Can be direct-seeded about four weeks before the last frost date. (Colorado State University Extension)
- Fall frosts improve the flavor. (Utah State University Extension)
- Grows best when temperatures stay at or below 75°F. (Utah State University Extension)
- Keep soil from drying out; dry soil makes cole crops strong-flavored. (Colorado State University Extension)
- Add organic mulch once temperatures climb above 80°F. (Utah State University Extension)
How the answer uses this
The planting window opens 4 weeks before typical last frost in your town and stays open while a planting still has 75 days to mature before the typical first fall frost. Inside the window the answer is Plant when the coldest of the next 7 nights stays above 25°F (no source gives a minimum night temperature, so the cold-damage temperature is used). Cover tonight shows when tonight's low is 25°F or colder while kale is normally in the ground.
Sources
- Utah State University Extension — checked Nov 11, 2026
- Colorado State University Extension — checked Nov 11, 2026
- Iowa State University Extension — checked Nov 11, 2026
- Colorado State University Extension — checked Nov 11, 2026
Guidance only. Extension advice is written for typical conditions; your soil, variety and microclimate matter.