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.
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.
There are at least 27 species of capsicum, though only five are cultivated. The others are wild species.
Most of the commonly grown varieties (such as bell, cherry and cayenne peppers, pimentos, jalapeños, Anaheim and New Mexico chiles) belong to C. annuum. There are hundreds, if not thousands, of varieties of this species. The peppers cross-pollinate readily and have many different common names and variations in shapes, so it’s not always easy to classify them.
Despite their love of heat, peppers need plenty of water and do best with regular, even watering.
Cultivars commonly recommended for cooler climates include ‘California Wonder’ and ‘Gypsy’ sweet bell peppers, the more pungent ‘Karlo’ and ‘Mexi-Bell’ bells, ‘Hungarian Yellow Hot Wax’, ‘Jalapa’ jalapeño, ‘Long Slim Cayenne’ and ‘Super Chili’ hybrid. I’ve had mixed results, depending on the weather.
The other types of cultivated Capsicum are:
C. chinense, popular with chile heads, which includes the fiery habanero, scotch bonnet, datil and congo chiles. The name means “from China,’’ though most experts believe this species originated in the Amazon Basin and spread from there to the Caribbean. Because the slow-growing plants can take between 80 and 120 days to mature, this species is a challenge in Chicago.
C. frutescens (shrubby), the pungent tabasco and bird chiles. These are primarily grown for hot-sauce manufacturing. They are compact plants, good for container growing, and a single plant can produce 100 pods.
C. baccatum, the fruity South American aji, and C. pubescens (hairy foliage), the intensely hot rocoto and manzana or peron chiles. Relatively new to North America, and grown mainly by chile aficionados, both require growing seasons of 120 days or more — not very practical for Chicago growers, in any case.