How to coax peppers into performing in Oregon's coolness

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Red and yellow peppers growing on pepper plant.
Red and yellow peppers growing on pepper plant.
Last Updated: 
June 17, 2010

CORVALLIS - Peppers thrive in heat. Though many Oregon regions lack a true hot climate, peppers can be successfully grown in our state with a little extra care.

May is too late to start peppers successfully from seed, but transplants are readily available from garden centers in May and June. To grow peppers from seed you need to start in February or March. Plant pepper transplants after all danger of frost is past and the night temperatures stay above 55 degrees - sometime after May 1 in most parts of Oregon.

Pepper plants thrive in warm, well-drained fertile soil. You can plant them up to as deep as the first true leaves. The plants should be placed between 18 to 36 inches apart.

For the first few days they are planted out in the garden, keep pepper plants well watered and protect from excessive wind and sun. Pinch off any premature blossoms or fruit that may have developed before transplanting.

If night temperatures in your area stay cool in the summer, the following techniques will help coax peppers into ripe fruit before the first frost:

  • Cover the soil around the plants with black plastic to help the sun warm the soil.
  • Grow peppers under cover for the first few weeks. Plant them under a cloche. Or surround each pepper plant with a round wire cage wrapped in clear plastic, to form a miniature heat-storing greenhouse. The cage should be about two feet tall. Leave the top open. Later on, in about July, when the plants are good sized, remove the cloche cover or plastic from the wire frame.
  • Select short season pepper varieties - Parks Early Thickset, Lady Bell, Early Cal Wonder 300, Golden Bell, Banana Supreme, Gypsy, Yankee Bell and Northstar peppers are OSU-recommended sweet pepper varieties said to mature from starts in an average of about 70 days.

Peppers are rich sources of vitamins A and C. They vary widely in pungency or "hotness," depending on the amount of capsaicin, a compound found in all peppers. "Sweet" peppers, with tiny amounts of capsaicin, include the blocky bell peppers, the pimiento and sweet cherry peppers. Most peppers are green as immature fruits, and then turn color as they ripen. They can be harvested immature (green) or mature (colored).

Capsaicin accumulates to highest levels in the tissue connecting the seeds with the wall of the pepper fruit (placenta) and in the seeds themselves. Removing this tissue can reduce this "heat".

"The hottest are the habeneros," explained Jim Myers, OSU vegetable breeder. "Habeneros, which belong to the Capsicum chinense species, also has the distinctive aromas that give Indian cuisine its characteristic flavor."

The first peppers should be ready to harvest eight to 10 weeks after transplanting. When fruits are mature, they are thick walled and well colored. Bell peppers can be left on the plant to ripen fully to a red, yellow or orange color, depending on the variety. Purple, white and chocolate-colored peppers are also available. Most peppers can be stored for a week or two in cool, moist refrigerated conditions. Some can be pickled, frozen as halves, cubed or stuffed.

Habeneros are reported to be 100 times as hot as the popular jalapeno. OSU doesn't recommend any habenero types because they require more heat than can typically be found during most Oregon growing seasons, said Myers. But if started early indoors and grown with season extenders such as plastic mulch, cloches or hot caps, they may be harvested successfully in Oregon.

Hot peppers can be traditionally dried. Pick and tie pepper stems together, gather a "ristra" with needle and thread, or pull out the entire plant and hang in a dark, warm area such as a garage to dry. Or remove the stems and seeds and freeze them. Be careful not to touch your eyes while handling hot peppers.

OSU Agricultural Experiment Station vegetable researchers have tested and recommend the following varieties of peppers as performing well in Oregon conditions:

  • (sweet, bell, green to red) Parks Early Thickset, Camelot, Fat 'N Sassy, Ace, Bellboy, Jupiter, Yankee Bell, North Star, Parks Whopper Improved, Vidi, Elisa, Lady Bell, Bell Tower, King Arthur.
  • (sweet bell, green to yellow) Golden Bell, Golden Summer, Labrador.
  • (sweet bell, green to orange) Ariane, Corona.
  • (sweet bell, green to purple) Lilac Bell, Purple Beauty.
  • (sweet bell, green to lavender to red) Islander.
  • (sweet bell, ivory to red) Snow White.
  • (specialty sweet types) Sweet Banana, Banana Supreme, Gypsy, Biscayne, Red Bull's Horn, Pizza, Lipstick.
  • (sweet cherry) Euro Jumbo Sweet Cherry.
  • (novelty, ornamental) Marbles, Riot, Ivory, Varengata. Riot and Marbles, 10 to 12-inch tall hot pepper plants are both developed by Jim Baggett, OSU professor emeritus of horticulture. These small pepper varieties can be grown in the garden or in pots on sunny patios, window planters or porches.
  • (mildly hot) Anaheim TMR 23, Fajita Bell, Paprika Supreme. These thin skinned Anaheim, Pasilla and Poblano or Ancho types are traditionally roasted and skinned before use.
  • (hot) Serrano, Volcano, Super Cayenne II, Tam Jalapeno.

For more information read Grow Your Own Peppers (PDF - EC1227) or visit the OSU Extension publications and video catalog.

Author: Carol Savonen
Source: Deborah Kean, Jim Myers