How to Grow Peppers

Timing matters more than for tomatoes

Peppers are slower and fussier about cold than tomatoes. Clemson notes that they grow very slowly in cool periods and do best with days at 70 to 85°F and nights at 60 to 70°F. Waiting until the soil has thoroughly warmed, at least 60°F, is the most useful thing you can do; the dates for your zone above already allow for this.

Start seed indoors 6 to 8 weeks before the last frost (Clemson, NC State), or 8 to 10 weeks according to Utah State, which grows larger transplants. Pepper seed is slow and needs warmth: at 68°F it takes about 12 days to emerge and at 59°F about 25, while at 77 to 86°F it comes up in about 8. Utah State germinates seed at 80°F, then grows seedlings at 65 to 75°F under lights. The ideal transplant is stocky, dark green and 5 to 8 inches tall with 6 to 9 leaves. Remove any flowers or fruit before planting, since they slow establishment.

In short-season areas, black plastic mulch laid before planting warms the soil, and row covers or hot caps protect young plants. Vent them when the air inside goes above 80°F, because heat during flowering makes flowers and young fruit abort.

Varieties for your region

Extension services recommend these for their own states:

• South Carolina (Clemson): bells Capistrano, Jupiter, Plato, Antebellum, Valencia and Vanguard; jalapeños Jalapeno M, Tula, Mitla and Fooled You; cayennes Carolina Cayenne and Charleston Hot.
• Texas (Texas A&M): sweet Bell Tower, Big Bertha, California Wonder, Gypsy, Jupiter and Yolo Wonder; hot Hidalgo Serrano, Hungarian Wax and jalapeño, plus Long Red Cayenne and TAM Mild Jalapeño.
• Utah (Utah State): sweet Big Bertha, California Wonder, Gypsy, Keystone Resistant Giant and Yolo Wonder L; hot Anaheim, Early Jalapeño, NuMex Big Jim and Serrano Hot.
• Florida (UF/IFAS): sweet California Wonder, Red Knight, Big Bertha and Cubanelle; hot Early Jalapeno, Hungarian Hot Wax, Anaheim Chile and Habanero, among others.

Planting and spacing

Peppers need full sun, at least 6 hours, and well-drained soil; Utah State recommends a raised bed where drainage is poor. Clemson suggests a pH of 6.0 to 6.5. Rotate: don’t plant peppers where tomatoes, eggplant, potatoes or peppers grew within the last 3 years.

Spacing advice ranges from 12 inches in the row (Clemson) to 18 inches (Utah State, Texas A&M); UF/IFAS gives 9 to 15 inches. Rows are 18 to 24 inches apart in Utah State’s guide and 3 feet in Clemson’s and Texas A&M’s. Set plants no deeper than their original root ball, unlike tomatoes, and transplant in the evening or on a cloudy day.

Water, mulch and feeding

Even moisture is critical, especially during flowering and fruit development. Clemson advises wetting the soil at least 6 inches deep each time and not letting it dry out between waterings once fruit is forming; Utah State suggests 1 to 2 inches a week, ideally by drip. Irregular watering causes both flower drop and blossom-end rot. Organic mulch helps, but hold it until the soil is above 75°F so it doesn’t keep spring soil cool.

Peppers need only moderate fertilizer. Clemson side-dresses ½ pound of calcium nitrate per 100 square feet 3 to 4 weeks after planting and again 3 to 4 weeks later; Utah State uses ¼ tablespoon of 21-0-0 per plant at 4 and 8 weeks. Texas A&M adds about 2 tablespoons of fertilizer per plant once the first fruit starts to enlarge. More nitrogen than this gives big plants with few peppers.

Hoe shallowly. Texas A&M warns that deep cultivation cuts pepper roots and slows growth. Hand-pull weeds close to the plants.

Regional notes

In the cold North and at high elevations, choose early varieties, use transplants and warm the soil with plastic. In the humid South, a fall crop is possible: Texas A&M sets fall plants out 12 to 16 weeks before the first expected frost, and Clemson recommends a fall crop on the South Carolina coastal plain but not in the Piedmont. In the low desert around Phoenix, the University of Arizona calendar sets peppers out in late winter and again in midsummer, and fruit set stalls whenever days pass about 90°F. In frost-rare Florida and zones 9 to 11, UF/IFAS notes that peppers set out in late winter often keep producing into summer.

Problems

• Flower drop: nights below 55°F, days above 90°F, or uneven watering.
• Blossom-end rot: a dark, sunken patch on the fruit’s blossom end, caused when interrupted water supply stops calcium reaching the fruit. Keep soil evenly moist but not soggy, and test soil calcium before planting.
• Bacterial leaf spot and bacterial wilt: Clemson calls these the two worst pepper diseases in home gardens. Buy disease-free transplants, rotate, and clear out plant debris and volunteer peppers.
• Viruses: tobacco mosaic spreads from tobacco products, so don’t smoke or use tobacco around plants; control aphids, which carry other viruses.
• Insects: aphids, thrips, flea beetles and caterpillars such as corn earworm. Handpick caterpillars or use Bt or spinosad.
• Sunscald: pale, papery patches on fruit exposed to hot sun; dense foliage and steady moisture reduce it.

Harvest and storage

Sweet peppers can be picked once full size with firm walls, while still green. Left on the plant, most turn red, yellow, orange or brown, and Clemson notes that fully colored peppers are sweeter than green ones. Jalapeños are ready at full size with a deep, dark green sheen. Pepper branches are brittle, so cut the stems instead of pulling. Picking regularly increases yields, according to Texas A&M. Before the first fall frost, you can pull whole hot pepper plants and hang them to finish.

Storage advice varies: Clemson recommends 45 to 50°F with high humidity for 2 to 3 weeks, Utah State 50 to 55°F for 1 to 2 weeks with a warning about chilling injury, and Texas A&M says to use refrigerated peppers within 3 to 5 days.