How to Grow Peppers in Containers, Temperature, Water and Harvest

Peppers are a warm-season crop that sets fruit best between about 70 and 80°F, and flowers can drop when nights are cool or afternoons are very hot. University of Maryland (UMD) Extension adds that improper watering, too much or too little, is the number one reason container vegetables fail. The notes below pull together what Iowa State, Colorado State and Maryland extension services say, as of October 2026.

1. Know your temperature window

Iowa State University Extension says peppers need a long, warm season, with daytime temperatures of 70 to 85°F best for plant growth. It adds that bell pepper flowers may abort and drop when night temperatures fall below 60°F or daytime temperatures rise above 85°F, and that maximum fruit set on bell peppers is generally at 70 to 80°F. Hot peppers usually set fruit better in warmer weather than bells do.

Colorado State University (CSU) Extension gives a slightly lower floor: peppers need nighttime temperatures above 55°F for pollen development. The numbers are not identical, but the message is: when nights are in the 50s, expect slow fruit set. This is also why the planting date comes after frost has passed. Iowa State says to transplant after the danger of frost, and that seeds started indoors should go in 6 to 8 weeks before the planting date.

2. Pot basics

Give each plant its own pot. CSU's container table lists peppers at a minimum of 8 inches deep and 2 to 5 gallons per plant, one plant per container. UMD's guidance for container size is larger: it puts full-size peppers among large vegetables needing 8 to 10 gallons and 12 to 16 inches of depth, and dwarf peppers among medium crops needing 4 to 6 gallons. CSU notes that larger sizes make the crop easier to care for by supplying more water and nutrients, and UMD warns against squeezing large plants into small containers.

UMD also says peppers benefit from some type of vertical support, as do tomatoes, cucumbers and eggplant, so push a stake or small cage in at planting time rather than after roots fill the pot.

For sun, Iowa State recommends at least six hours of direct light a day.

3. Watering

UMD puts it bluntly: improper watering, both too much and too little, tends to be the biggest limiting factor and the number one reason for failure in container vegetables. Its rules:

• Press a finger into the soil; water when it is dry.
• Water until it runs out of the drainage holes. Several shallow waterings are not nearly as effective as one long one.
• Apply water at the base, not on the leaves, to cut down disease.
• Empty saucers after watering or rain, and use pot feet to improve drainage.
• If the pot dries out so far that the soil pulls away from the edge, water runs through the gap. Soak the pot halfway in a bucket or sink until the surface is moist.

Iowa State adds that an adequate moisture supply during flowering and fruit set is important. It also describes blossom end rot, the brown, leathery patch at the fruit's blossom end. It is caused by a calcium deficiency in the developing fruit, and the factors that contribute include fluctuating soil moisture, high nitrogen fertilization and root pruning. In a pot, "fluctuating moisture" is the likeliest trigger.

4. Feeding

Regular watering leaches nutrients out of a pot. UMD says long-season crops such as tomato, cucumber, eggplant and pepper may need light fertilizing about every 2 weeks for a continuous harvest. Slow-release pellets mixed into the potting mix feed a little with every watering. If the mix already contains fertilizer, plants should have enough for a few weeks. Follow the label: too much can burn plants and build up salts in the pot. UMD also says never to add lime, wood ashes or gypsum to commercial growing mix, because lime is already included.

Iowa State lists high nitrogen fertilization among the factors that contribute to blossom end rot, which is another reason to stay within label rates.

5. Sunscald

Iowa State describes sunscald as a soft, light-colored patch that dries to white and papery on the side of the fruit exposed to the sun. Keeping a plant leafy by fertilizing lightly and controlling leaf diseases reduces the risk. Leaf diseases that defoliate plants raise the risk.

6. Harvest

Iowa State says bell and hot peppers can be picked green or fully ripe. Bells are usually picked large and firm while still green, but left on the plant they ripen to red, yellow, orange, purple or other colors depending on the cultivar. Fully ripe bell peppers are slightly sweeter and have more vitamins than green ones.

For hot peppers, Iowa State advises gloves and ventilation when handling and processing, and not touching eyes or other sensitive areas. If an ingested hot pepper causes discomfort, it suggests eating something fatty like cheese or drinking milk.

For a sense of the heat scale, Iowa State's Scoville table puts bell peppers at 0, poblano and Anaheim at 1,000 to 2,500, jalapeno at 2,500 to 10,000, and habanero and Scotch bonnet at 100,000 to 350,000 Scoville heat units. Seeds are not the source of the heat. Iowa State says capsaicin is produced in the placenta, the membrane that joins the seed to the fruit.

7. Key takeaways

• Peppers set fruit best at 70 to 80°F; flowers drop with nights under 60°F (Iowa State) and pollen needs nights above 55°F (CSU).
• One plant per pot, as large a pot as you can manage, with a stake or cage at planting.
• Check the soil with a finger, water until it drains, and keep moisture steady to avoid blossom end rot.
• Feed lightly about every 2 weeks, at label rates.
• Bells can be picked green or left to color; fully ripe ones are slightly sweeter but take longer.