Plenty of vegetables grow well in Denver, Colorado, but if you don’t know how to deal with the climate, you may have a hard time. Colorado’s average elevation is 6,800 feet above sea level. Because of its high elevation, the sun is intense and the humidity is low. The state also sees some extreme weather and has poor soil conditions. With the right vegetables, though, you can manage all of these obstacles.
Potatoes are a hardy vegetable that can survive Denver’s soil, sunlight and temperatures. Potatoes need soil with organic matter, but do not add too much fresh manure or compost. Plant potatoes once the soil temperature rises above 50 degrees F. Plant them 4 inches deep around 8 a.m. The spacing between your potatoes varies by variety, but a good starting point is 12 to 15 inches between plants and rows. Use clean straw as mulch.
Many vegetables known as cole crops will grow well in Denver, Colorado. Popular cole crops include broccoli, cauliflower and cabbage. Cole crops have shallow roots and require moist, well-drained soil. Because Colorado has a lot of clay soil, you must prepare your soil first. You can do this by adding 3 to 4 inches of organic compost. You should also add a plant starter fertilizer before planting any cole crops. Add it again at three weeks and five weeks. This will increase your harvest by 20 percent. Cole crops grow best in temperatures between 65 and 80 degrees F, so the best time to plant in Denver is in early July.
Most leafy vegetables are semi-hardy vegetables and will also grow well in Denver. Some examples of leafy vegetables include lettuce, spinach and Swiss chard. Prepare your soil for leafy vegetables if it is the common clay soil found in Colorado; use organic mulch such as dry grass clipping to reduce the soil temperatures in the summer. Leafy vegetables need 1 ½ inches of water each week. The best time to plant leafy vegetables is from middle to late summer. You can also plant in the middle of fall, but cover the seedling with organic mulch to protect them.
Vegetables from the onion family are hardy and will survive in Colorado. Besides onions, this family includes garlic, leeks and shallots. Vegetables in the onion family flourish on organic mulch because it cools the soil and controls weeds. You should only plant varieties that will bulb with day lengths of 14 to 16 hours and temperatures above 65 degrees F. This is because the length of night can trigger early bulb development. Plant vegetables from the onion family as soon as you can in the spring.