Gardening in Colorado can be challenging, especially to newcomers. In addition to cold weather, Colorado's low humidity, fluctuating temperatures, heavy calcareous soils and drying winds often restrict plant growth. Knowing how to select plants that will do well and by manipulating the soil and microclimate will help gardeners grow vegetables successfully in Colorado.
All types of lettuce grow well in a high-altitude garden. With an extra bit of effort at planting time, bountiful lettuce yields are possible on a year-round basis.
Using a fertile soil that retains moisture yet drains well is ideal for growing lettuce. Most Colorado soils will need the addition of organic compost. The mixture will enable moisture to drain and the oxygen to filter into the root zone. Adding nitrogen from well-composted manure or cottonseed meal will ensure rapid, leafy growth production.
Installing a soaker hose an inch or more beneath the soil surface in a slightly mounded row before planting seed keeps the soil surface dry. Doing so will reduce the chances of predation and disease caused by pests associated with moist conditions. Sowing lettuce seed directly into the soil, 1/4 to 1/2 inch deep, and covering the beds with a floating row cover tunnel will protect the plants throughout the growing season. Lettuces prefer cool temperatures; the seeds sprout best at 60 to 65 degrees Fahrenheit. At 80 degrees Fahrenheit and above, lettuce seeds may not germinate at all.
Head, romaine, leaf and Boston are examples of lettuces that grow well in Colorado.
Spinach can grow in Colorado. It grows in a wide range of soils, provided the soils are moist and fertile. It takes spinach 30 days from seed to maturity. Seeding about every ten days will provide a continuous supply of spinach throughout the year. Seeding into August is possible, as spinach will tolerate a light September frost.
Sow seeds 1/4 to 1/2 inch deep, spacing about an inch apart. Plant in an area that receives at least six hours of direct sun. Keep garden soil moist, but not waterlogged. Spinach seeds may be difficult to germinate; however, you can try different methods. For example, covering the seed beds with boards can help hold the moisture in the ground and shade the soil. Covering the seed beds with loose mulch, such as old straw, and watering every day works well to shade the soil, keeping it cooler and moist. Avoid mulching too heavily or the germinating plants won't be able to push through.
Savory, tyee, melody and winter bloomsdale are varieties of spinach that can grow well in Colorado.
Peppers thrive in a well-amended soil that contains plenty of organic matter, supplemented with a balanced fertilizer. You may choose one with slightly higher nitrogen and phosphorous levels. Place peppers in an area that will receive the most sun and plant 18 inches apart with rows three feet apart to ensure that the plants will get enough light even as they grow bigger. Similar to tomatoes, peppers may yield heavy crops; therefore, using tomato cages can prevent plants from splitting or falling over.
Avoid planting peppers in the garden in early spring. Plant in late May or early June when the nighttime temperatures consistently stay above 50 degrees Fahrenheit ensures a bountiful harvest. Protect from wind and cover the plants with hot caps during unexpected cooler weathers.
Habanero, cayenne and red chili are some examples of peppers that can grow in Colorado.