Washington · zones 6b–9a
When to plant bell peppers in Washington.
Sow or transplant between Apr 30 to Jun 21 in a typical year, keyed to Washington's median last frost around Apr 14. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Bell Peppers dates for a typical Washington season.
1 · Start indoors
Mar 19 to May 10
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
Apr 30 to Jun 21
Keyed to the ~Apr 14 last frost. Sow 0.25" deep, 18" apart.
Harvest
~70 days later
~4 lb per plant over ~8 weeks.
Washington spans more than one climate: Zone 8 is the most common zone, but the state runs 6b to 9a. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.
Washington growing notes
Peppers pick a side of the Cascades in Washington.
The heat threshold that decides fruit set
Pepper flowers refuse to set once the thermometer holds above 90 during the day and stays above 75 overnight, a tighter margin than tomato gets in the same garden; the difference in Washington is which side of the Cascades sees that kind of heat at all. East of the mountains, the irrigated Columbia Basin regularly delivers exactly that hot summer stretch, which can stall pepper set for a week or two at the peak of summer even as the plant itself looks perfectly healthy.
West of the mountains, Puget Sound gardens rarely see days hot enough to trigger that fruit-set failure, but they face the opposite problem: summer nights commonly stay cool enough that a slow-maturing bell pepper, needing roughly 70 days in the ground after transplanting, struggles to size fruit before the season runs out. Black plastic mulch laid ahead of transplanting, banking real soil warmth, helps close that gap on the cooler west side.
A stalled harvest east, a slow one west, different fixes
On the hot Columbia Basin side, the workaround for the 90/75 stall is patience rather than intervention: keep the plant otherwise healthy through the worst heat, water consistently so it is not also fighting drought stress, and expect fruit set to resume once nights ease back down later in summer, since the plant itself is not damaged by the heat, only temporarily unable to set new fruit. Fruit already pollinated before the stall keeps sizing normally through the hot stretch.
On the cool west side, row cover left on through the plant's early weeks, then removed once flowering starts so pollinators can reach the blossoms, buys the plant a faster start that helps offset the slower fruit development a cool Puget Sound summer otherwise causes; a pepper transplanted even a week later than optimal on the west side often never fully catches up before fall weather arrives.
Hornworms and blight, watched differently on each side
Tomato hornworm, the same large green caterpillar that targets tomatoes, feeds on pepper foliage just as readily and is easiest to find by checking for fresh, ragged holes and the dark droppings that collect on leaves below the feeding site, since the caterpillar itself is camouflaged well enough to miss on a quick glance. A weekly check of a handful of plants, looking down rather than just at the foliage, catches an infestation before it strips a plant of leaf cover fruit needs for protection from sunscald.
Bacterial leaf spot and Phytophthora blight, a soil-borne rot that can collapse a plant at the base overnight in saturated ground, both run higher on the humid west side than in the dry Columbia Basin, so west-side growers benefit more from staking plants to keep the canopy open and dry after rain, while east-side growers dealing with drip or overhead irrigation should still aim water at the base of the plant rather than the leaves, since both problems spread fastest wherever leaves or soil stay wet longest.
In Washington: watch for
The pests that find bell peppers here.
A middle-length season, about 187 frost-free days, means pepper, bell overlaps aphids for a stretch each summer. Check plants every week or two and treat early.
Clusters on new growth, sticky leaves, curling tips. Green peach aphid spreads virus.
Organic fix: Blast with water, then insecticidal soap or neem.
Bacterial leaf spot
Small water-soaked spots that turn brown; badly spotted leaves drop.
Organic fix: Plant resistant varieties, avoid overhead watering, rotate out of nightshades.
Plant wilts and collapses at the soil line after a bed stays soggy.
Organic fix: Plant on raised ground for drainage; remove collapsed plants and do not replant there.
Tiny shot-hole pits peppering young leaves.
Organic fix: Row cover the seedlings; healthy transplants outgrow the damage.
Your season math: Washington gives bell peppers about 187 frost-free days, and it needs roughly 70 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting bell peppers in Washington: questions
When should I plant bell peppers in Washington?+
In a typical Washington year, sow bell peppers or set out transplants between Apr 30 to Jun 21, keyed to the state's median last frost around Apr 14. Your exact dates shift with your ZIP code and microclimate.
When do I start bell peppers seeds indoors in Washington?+
Start seeds inside about 6 weeks before set-out: roughly Mar 19 to May 10 for a typical Washington season.
What USDA zone is Washington?+
Washington spans zones 6b–9a, mostly zone 8. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many bell peppers plants do I need?+
Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.