Growing Peppers in a Canadian Climate

Growing peppers in Calgary means working with about 110 frost-free days. That's not a lot when some pepper varieties need 120 days or more to reach maturity. But with indoor starts, the right variety selection, and a little stubbornness, you can grow peppers that rival anything from warmer climates. I've been doing it for years, and every September I have more peppers than I know what to do with.

Start Early, Start Inside

Pepper seeds need warmth to germinate, ideally 27 to 32 degrees Celsius. In Alberta, that means starting seeds indoors in late February or early March, a full two months before your last frost date. Use a heat mat under your seed trays. Without one, germination is slow and unreliable, especially for superhot varieties like ghost peppers and habaneros, which can take 3 to 4 weeks to sprout even under ideal conditions.

Start in small cells or pots with a sterile seed-starting mix. Keep the soil moist but not waterlogged. Once seedlings have their first true leaves (the second set of leaves after the initial seed leaves), pot them up into 4-inch containers. Give them the strongest light you can manage. A south-facing window is rarely enough; supplemental grow lights for 14 to 16 hours per day will produce much stockier, healthier transplants.

Variety Selection

Not every pepper variety is suited to a short Canadian growing season. Here are reliable producers in Zone 3-4:

• Early Jalapeno (65 days to maturity) is nearly foolproof. Sets fruit quickly and produces heavily.
• Hungarian Hot Wax (70 days) tolerates cooler temperatures better than most peppers and produces long, waxy pods with medium heat.
• Cayenne (75 days) is a prolific producer of thin-walled peppers that dry easily for winter use.
• Habanero (100+ days) needs a long indoor start and the warmest spot in your garden, but will produce in Calgary if you start seeds by mid-February.
• Ghost Pepper (120+ days) is the limit of what's realistic outdoors in Calgary. Start in January and use a cold frame or greenhouse to extend the season.

Transplanting

Don't rush transplanting. In Calgary, the last frost date is typically around May 25, but late frosts can hit into early June. Harden off your seedlings by setting them outside for increasing periods over 7 to 10 days. Start with an hour of indirect light and work up to full days. Peppers are tropical plants and cold shock will set them back weeks.

Plant in the warmest, most sheltered spot in your garden. South-facing walls, raised beds with dark soil, and areas protected from wind are ideal. Peppers want soil temperature above 18 degrees Celsius. Planting into cold soil stalls growth even if air temperatures are warm.

Season Extension

Cold frames, row covers, and simple plastic hoop tunnels can add 2 to 4 weeks to each end of the season. That's the difference between a handful of green peppers and a full harvest of ripe, mature fruit. A cold frame over a raised bed is the single most effective tool for prairie pepper growing. You can build one from an old window and some lumber in an afternoon.

When fall frost warnings arrive and you still have green fruit on the plants, pick everything. Green peppers will ripen indoors on a sunny windowsill over 1 to 2 weeks. They won't be quite as flavourful as vine-ripened fruit, but they'll be leagues better than anything from the grocery store.