Growing Chili Peppers in Chicago
Regional gardener Leah Zeldes shares her insight on growing various strands of peppers in Chicago.
June/July 2004
By Leah A Zeldes
The Chicago climate rarely stoops to moderation. Typically, we get a long, cold, wet spring followed by a sustained blast of fiercely hot temperatures, leaving me wishing for just a couple of weeks, at least, of mild, sunny, 75-degree, perfect gardening weather.
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Last summer, though, stayed relatively cool and, being the fickle gardener I am, I actually hoped for a rise in mercury levels. I wanted a bumper crop of chiles — and Capsicum likes it hot.
Pepper plants won’t set fruit unless night temperatures are between 65 and 85 degrees. Chiles don’t reach their full pungency if it’s too cold: Peppers that ripen at daytime temperatures between 85 and 95 degrees can be twice as hot as those maturing at lower temperatures. Peppers also may take longer to ripen in cool weather.
Even during normal Chicago growing seasons (if we can be said to have any), growing peppers, especially the tropical chiles, is a challenge. Frequently, they don’t mature before the first frost, so achieving nice, red-ripe fruits is a real triumph.
You can improve your chances for a spicy harvest by growing early-maturing varieties. Warming the soil by covering it with clear plastic for a couple of weeks before setting out seedlings also helps, along with black-plastic mulch around the plants to keep soil temperatures high and to block weeds, which easily can defeat pepper plants. Other tricks include planting in raised beds that slope to the south and using row covers to keep the heat in around the plants.
It’s not too late to raise the heat around your peppers now, as early blooms are more apt to produce fruit than later ones. If temperatures in your part of the world soar to the terrible highs we sometimes get, you may want to offer the plants a bit of shade during the hottest parts of the day. If temperatures rise above 95 degrees in the daytime or 86 degrees at night, fruit set will be impaired.
Despite their love of heat, peppers need plenty of water and do best with regular, even watering—at least 2 inches per week—especially after the fruit have set. Chile plants do not, however, need much fertilizer. Too much nitrogen will create a lot of leafy growth at the expense of peppers. In fact, the plant may even drop its flowers and abort small pods already formed.