When to plant swiss chard in Montana
Montana’s average last spring frost is May 15, and the first fall frost typically arrives around September 15 — about 123 frost-free days (USDA zones 3a, 3b, 4a, 4b, 5a, 5b, 6a). Swiss Chard needs 50–60 days to mature, which fits comfortably within Montana's growing season.
Montana covers a wide range of climates, so your exact frost dates may differ from the state average by two weeks or more. For dates tuned to your town, use the calendar generator.
When to plant swiss chard in Montana: the short answer
For a spring planting, plant out Apr 24 – May 11, with seeds started indoors Apr 10 – Apr 24. Seeds germinate in soil from 40 to 85°F.
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow swiss chard in Montana, step by step
- Start seeds indoors (Apr 10 – Apr 24). Sow seeds 0.75 inch deep in seed-starting mix under bright light. They take 5-14 days to sprout, fastest in soil around 70°F. Harden seedlings off for a week before they go outside.
- Prepare the bed. It needs six or more hours of sun for the best growth, though four to six hours in partial shade is enough and loose soil at least 12 inches deep, with a pH between 6.0 and 7.5. Dig in compost before planting.
- Plant out (Apr 24 – May 11). Space plants about 9 inches apart in rows 18 inches apart. It tolerates a light frost but not a hard freeze. As a cool-season crop it does best before summer heat arrives in Montana.
- Water and feed. Give it steady, even moisture, about an inch of water a week from rain or the hose.
- Watch for pests and problems. Pests: leaf miner, aphids, flea beetle. Diseases and disorders: cercospora leaf spot, downy mildew.
- Harvest (from about Jun 20 – Jun 30). Swiss Chard takes 50-60 days to reach harvest. One of the most heat-tolerant leafy greens - a single spring sowing usually carries through summer into fall if kept picked.
Figures come from our crop data; dates use Montana’s average frost dates. More in the full swiss chard growing guide.
Swiss Chard planting dates by USDA zone in Montana
Montana spans USDA zones 3a, 3b, 4a, 4b, 5a, 5b, 6a. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the swiss chard dates shift with them.
When to plant swiss chard in nearby states
Questions gardeners in Montana ask
When is the best time to plant swiss chard in Montana?
Plant swiss chard transplants outdoors in Montana between April 24 and May 11. That timing is set by Montana's average last spring frost of May 15; Montana spans several climates, so cooler and higher parts of the state run later.
When should I start swiss chard seeds indoors in Montana?
Start seeds indoors between April 10 and April 24, about 4 weeks before the last frost, so the seedlings are ready to plant out from April 24.
Can I plant swiss chard in the fall in Montana?
Yes. For a fall crop, sow between June 27 and July 14, so the crop matures in cool weather before Montana's first frost around September 15.
When will swiss chard planted in Montana be ready to harvest?
Planted on time, swiss chard is usually ready from about June 20 to June 30, 50-60 days after planting.
When is the last frost in Montana?
On average around May 15, with the first fall frost around September 15 - about 123 frost-free days. Your town may differ by two weeks or more.