Colorado vegetable gardening success depends, in part, on which part of the state you live in. Gardeners on the Western Slope, near Grand Junction, can grow almost any vegetable successfully, while those living in the mountains face the challenges of poor soil and a short growing season. Gardeners in the Denver metro area can grow most crops successfully, with a few caveats: amend the soil thoroughly with compost and manure, use row covers and cloches to extend the growing season and expect to water the garden two to three times per week.
Colorado's cool, wet springs are ideal for growing greens such as lettuce, spinach, kale and broccoli. Plant these crops between mid-March and late-April, depending on where you live, because they bolt and run to seed as soon as the weather gets hot. Many of these crops turn bitter during dry weather so monitor the soil carefully, especially if you have the sandy soil that's common east of Denver.
Plant potatoes, carrots and fennel from mid-to-late April for a late summer crop. If you have clay soils, try using raised beds or plant small varieties. The heavy soils found throughout much of the Front Range stunt the growth of long carrots, causing them to be deformed or crooked. Shorter varieties grow successfully, though.
Beans grow beautifully in Colorado's warm, dry climate. They are rarely bothered by pests or disease and mature long before the first fall frost. Beans will also come back if hit by a light hailstorm, unlike many garden vegetables. Plant either row or bush beans after the last expected frost, which is typically mid-May, according to the Colorado State University Extension.
Tomatoes, Peppers and Eggplants
Tomatoes, peppers and eggplant all grow well in Colorado, although most gardeners find that chile peppers are more successful than bell peppers in Colorado's dry climate. Plant these heat-loving crops two to three weeks after the last expected frost, or use cloches and row covers to keep them warm. Monitor the soil moisture carefully to avoid blossom end rot or cracked skins from over watering. Heirloom varieties that might succumb to disease in more humid regions grow easily in Colorado.
Even the most inexperienced gardener can grow zucchini in Colorado. In fact, gardeners are often tired of zucchini long before it is done producing. Pumpkins also grow well in Colorado's dry climate and make decorative accents for fall. Plant both from seed after the last expected frost and give them plenty of room to grow.