When to plant bell peppers in Idaho
Idaho’s average last spring frost is May 10, and the first fall frost typically arrives around September 25 — about 138 frost-free days (USDA zones 3b, 4b, 5b, 6a, 6b, 7a). Bell Pepper needs 60–90 days to mature, which fits comfortably within Idaho's growing season.
Idaho 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 bell peppers in Idaho: the short answer
For a spring planting, plant out May 17 – Jun 3, with seeds started indoors Mar 8 – Mar 22. Wait until the soil is at least 60°F and frost is over.
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 bell peppers in Idaho, step by step
- Start seeds indoors (Mar 8 – Mar 22). Sow seeds ¼ inch deep in seed-starting mix under bright light. They take 7-14 days to sprout, fastest in soil around 82°F. Harden seedlings off for a week before they go outside.
- Prepare the bed. They need at least six to eight hours of direct sun a day and loose soil at least 12 inches deep, with a pH between 5.5 and 7.0. Dig in compost before planting.
- Plant out (May 17 – Jun 3). Space plants about 18 inches apart in rows 30 inches apart. It is killed by frost, so nothing goes outside until the danger has passed.
- 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: aphids, flea beetle, pepper maggot, tomato hornworm. Diseases and disorders: bacterial leaf spot, anthracnose, blossom-end rot (calcium disorder), phytophthora blight.
- Harvest (from about Jul 23 – Aug 22). Bell Pepper takes 60-90 days to reach harvest. Needs warm soil; wait until nights stay above 55 F to transplant. Green peppers are just unripe coloured peppers left another 2-3 weeks.
Figures come from our crop data; dates use Idaho’s average frost dates. More in the full bell pepper growing guide.
Bell Pepper planting dates by USDA zone in Idaho
Idaho spans USDA zones 3b, 4b, 5b, 6a, 6b, 7a. 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 bell pepper dates shift with them.
| Zone | Last frost | First frost | Season | Start indoors | Plant bell pepper |
|---|---|---|---|---|---|
| Zone 3 | May 15 | Sep 15 | 120 days | Mar 13 – Mar 27 | May 22 – Jun 8 |
| Zone 4 | May 10 | Sep 25 | 135 days | Mar 8 – Mar 22 | May 17 – Jun 3 |
| Zone 5 | Apr 30 | Oct 5 | 160 days | Feb 26 – Mar 12 | May 7 – May 24 |
| Zone 6 | Apr 15 | Oct 15 | 185 days | Feb 11 – Feb 25 | Apr 22 – May 9 |
| Zone 7 | Apr 5 | Oct 25 | 200 days | Feb 1 – Feb 15 | Apr 12 – Apr 29 |
When to plant bell peppers in nearby states
Questions gardeners in Idaho ask
When is the best time to plant bell peppers in Idaho?
Plant bell pepper transplants outdoors in Idaho between May 17 and June 3. That timing is set by Idaho's average last spring frost of May 10; Idaho spans several climates, so cooler and higher parts of the state run later.
When should I start bell pepper seeds indoors in Idaho?
Start seeds indoors between March 8 and March 22, about 8 weeks before the last frost, so the seedlings are ready to plant out from May 17.
What is the latest I can plant bell peppers in Idaho?
About July 27. Bell peppers need at least 60 days to mature after transplanting, and frost around September 25 ends the season, so later plantings risk being cut short.
When will bell peppers planted in Idaho be ready to harvest?
Planted on time, bell peppers are usually ready from about July 23 to August 22, 60-90 days after transplanting.
When is the last frost in Idaho?
On average around May 10, with the first fall frost around September 25 - about 138 frost-free days. Your town may differ by two weeks or more.