Start by checking what the pepper is supposed to do. Most bell and hot peppers start green and turn red when fully ripe, but some varieties ripen to yellow, orange, purple or brown, and a few start white and stay that way. Look at the seed tag or catalog listing: many give days to harvest for the green stage, and the colored stage comes later. If the fruit is full size, firm and glossy but still green, and the variety is meant to turn red, nog is wrong with the plant. It is waiting on time and heat.
Time is the most common answer. Oregon State University Extension says peppers take at least 45 to 55 days after pollination to produce harvestable fruit, and Utah State University Extension counts 35 to 45 days from flowering to full color. In practice, a bell pepper that has reached full green size often needs another two to four weeks on the plant to finish coloring. Large, thick-walled bells tend to take the longest; small hot peppers usually color sooner. A plant set out late, or one that stalled for weeks after , may run out of season before its fruit turns.
Cool weather slows everything down. Peppers grow best with days of 70–80°F and nights of 60–70°F, and Oregon State notes that where days and nights run cooler, fruit can take an extra 15 to 20 days to mature. That is why fruit set in the second half of summer often stays green as nights lengthen and cool toward fall. Too much sun on the fruit can cause trouble as well: Utah State notes that sun-exposed fruit can overheat, dry out and color unevenly, so don't strip leaves to expose peppers.
Leave full-size fruit on the plant as long as the weather allows, and water deeply whenever the t inch of soil is dry so the plant doesn't stall. Black plastic warms the soil, and a on cool nights holds in heat; vent covers when the air under them passes 80°F. Before your first fall frost, pick every full-size pepper. Fruit that has started to color can keep coloring off the plant if held warm, around 68–77°F. Fully green bells usually stay green, but they are still good to eat.
Next year, choose a variety whose days to the colored stage fit your season, not only its days to green. If your frost-free season is short, favor early or smaller-fruited peppers; Oregon State notes some varieties shouldn't be grown where the frost-free season is under 120 days. Start seeds indoors 8 weeks before your last spring frost and transplant about 2 weeks after it, once the soil has warmed to at least 60°F. Utah State notes that transplants mature about 4 weeks ahead of peppers, and that black plastic mulch brings fruit in earlier.
- SunscaldBleached, papery patches on sun-exposed fruit — usually appears after the leaf canopy is reduced.
- Fruit CrackingTomatoes crack at the stem end or shoulder, cabbage heads split, and carrots split lengthwise — usually after heavy rain follows dry weather.
- Early BlightDark spots with concentric rings on lower leaves that yellow and drop, working up the plant.
- Crown RotThe base of the plant turns brown and soft at the soil line, and the plant collapses — caused by wet-soil pathogens attacking the crown.
- MoleRaised surface tunnels and conical soil mounds across garden beds — moles tunnel for earthworms and grubs, not plant roots.
- Why do my pepper plants keep dropping their flowers?Pepper flowers usually drop from stress: nights below 60°F or above 75°F, very hot days, uneven watering, or too much nitrogen. Most plants start setting fruit again once the weather settles.
- Why are my pepper plant leaves turning yellow?Peppers yellow their lower leaves most often from cold stress or nitrogen deficiency — they're extremely sensitive to cool soil and temperatures below 55°F at night.
- How can I extend my growing season in fall?Row cover fabric, cold frames, and switching to cold-hardy crops are the three most reliable tools for extending production 4–6 weeks past your first fall frost.