Planting Warm Season Vegetables by Donna Duffy

Photo courtesy CSU Extension

Yes, it's officially Spring! On those warm 60+ degree days, it's tempting to get your warm season vegetables into the ground. Before you take that leap, here's advice from PlantTalk Colorado that may save you time and disappointment.

Beans, corn, cucumbers, melons, okra, eggplant, peppers, tomatoes, pumpkin and squash are warm-season vegetables. Many of these crops grow under cool conditions, but won't produce fruit when night temperatures are in the 50 degree Fahrenheit range. They need warm temperatures to grow and mature. Once the fruit begins to form, it needs up to two months of frost-free weather. Warm-season vegetables are typically not suited for high elevation gardens.

Plant warm season vegetables in rich garden soil that gets plenty of sunlight and drains well. Work the soil early in the spring, adding one and one-half inches of organic material. Too much nitrogen promotes leaf growth but delays flower and fruit production, so choose organic material carefully.
To help warm the soil, you can cover rows with black plastic mulch early in the season. Seeds can be planted through plastic mulch or directly in garden soil, depending on the local weather and recommendations for individual vegetables.

Check the seed packet for the number of days until maturity so that there will be enough time for plants to grow before the first killing frost.

Transplants are plants started indoors or in greenhouses to get an early start on the growing season. Hardened transplants can be planted through plastic mulch or directly in soil anytime after the last average frost date.

Photo courtesy cloversgardencenter.com

In Denver, the last frost is around May 10. Colorado's climate is different each year so careful attention to the current year's local weather conditions is extremely important.

Protect seedlings from frost and cold air by using hot caps or other insulation methods that use water to hold the sun's heat. This protection can add up to two weeks to the gardening season.

Check out CSU Extension's Vegetable Planting Guide for specific recommendations for cold and warm season vegetables.