Swiss chard
What Plant Yet? knows about swiss chard, and where each number comes from. For today's answer, pick your town.
Planting numbers
- Frost category
- Semi-hardy Source: Colorado State University Extension
- Plant outdoors
- From 2 weeks before typical last frost up to the frost date Given for semi-hardy crops as a group. Source: Colorado State University Extension
- Start seeds indoors
- 5–6 weeks before planting out Source: Utah State University Extension
- Cover at or below
- 32°F Source: Utah State University Extension
- Grows once daytime temperatures reach
- 40°F Given for semi-hardy crops as a group. Source: Colorado State University Extension
- Days to harvest
- 60 Source: Colorado State University Extension
Left out because we found no university extension source for it: minimum night temperature. We don't estimate.
Growing tips
- Needs steady water and rich soil for good-quality leaves. (Colorado State University Extension)
- Seed can go in once soil reaches 40°F. (Utah State University Extension)
- Grows best when temperatures stay at or below 75°F. (Utah State University Extension)
- Cut outer leaves and let plants regrow for a continuous harvest. (Colorado State University Extension)
- Thin when seedlings have three to four true leaves. (Utah State University Extension)
How the answer uses this
The planting window opens 2 weeks before typical last frost up to the frost date in your town and stays open while a planting still has 60 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 32°F (no source gives a minimum night temperature, so the cold-damage temperature is used). Cover tonight shows when tonight's low is 32°F or colder while swiss chard is normally in the ground.
Sources
- Colorado State University Extension — checked Nov 11, 2026
- Utah State University Extension — checked Nov 11, 2026
- Colorado 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.