Regional guide
Colorado High-Elevation Mountain Vegetable Garden
CSU Extension mountain vegetable guide for Colorado gardeners over 7,500 feet who need short-season, frost-aware, cool-season planning.
Climate signals
- CSU Extension defines high elevation or mountain vegetable gardening in Colorado as anything over 7,500 feet.
- The source gives the Gilpin County Extension office at 9,300 feet as an example with a June 10 average last frost and a September 15 average first frost.
- Many Colorado mountain sites can have fewer than 90 frost-free days, and lower-elevation valleys can be cooler than surrounding hillsides because cold air sinks at night.
- Cool-season vegetables are the easiest and most productive crops for mountain gardens.
- Warm-season vegetables such as tomatoes, corn, winter squash, beans, cucumbers, melons, peppers, eggplant, and okra often lack enough growing degree units; bush beans and summer squash are the warm-season crops most likely to succeed.
Planning notes
- Choose varieties with the least number of days to harvest because shorter-season selections require fewer GDUs; the source warns that listed maturity days may take longer in mountain conditions.
- Use a site with six to eight hours of full sun when possible, while four to six hours can be enough for leafy greens; a south-facing, slightly sloped area is best for warming soils in spring.
- Floating row cover is useful in mountain gardens because it can provide frost protection down to about 24 F, reduce drying winds, and help hold moisture.
- Direct-seed frost-tolerant plants such as kale, kohlrabi, lettuce, spinach, turnips, chard, mustard, beets, carrots, cabbage, endive, peas, and radish four weeks before the last frost when conditions allow.
- A soil thermometer is more accurate than frost dates alone; the source says to plant frost-tolerant crops when soil 6 inches deep is 40 F at 8:00 a.m. and to wait if the ground is frozen or snowy.
- Start longer-season crops such as broccoli, cauliflower, leeks, and Brussels sprouts indoors 6 to 8 weeks before the last frost and plant them out two weeks before the last frost after hardening off.
- Treat beans as experimental warm-season crops for mountain gardens and plant them after all danger of frost has passed; avoid using the difficult warm-season crop list as mountain priority recommendations.
- Because many mountain gardens have only one cool season, plant smaller amounts every two weeks for succession instead of planting every bed as soon as the ground thaws.
- Use block planting to save space and water, keeping blocks no wider than 3 to 4 feet so they can be tended without stepping into the bed.
- Check moisture instead of watering by a fixed schedule; irrigate when the top 2 to 4 inches of soil is dry to the touch.
- For season extension, floating row covers can add a couple weeks on either side of the season, and plastic-covered low tunnels can add about a month at either end when managed and ventilated.
- Use these priority catalog links as crop-level examples for CSU's mountain crop groups, not as Colorado mountain cultivar recommendations.
Catalog crop examples
These catalog entries match crops covered by the regional timing source; variety-specific details remain tied to each seed entry's own source.
- Black Seeded Simpson Lettuce Vegetable · Cool · 45 days
- Astro Arugula Vegetable · Cool · 35 days
- Lacinato Kale Vegetable · Cool · 60 days
- Bloomsdale Spinach Vegetable · Cool · 42 days
- Bright Lights Swiss Chard Vegetable · Shoulder · 55 days
- Georgia Southern Collards Vegetable · Cool · 65 days
- Golden Acre Cabbage Vegetable · Cool · 64 days
- Green Curled Endive Vegetable · Cool · 85 days
- Vit Mache Corn Salad Vegetable · Cool · 50 days
- Danvers 126 Carrot Vegetable · Shoulder · 70 days
- Detroit Dark Red Beet Vegetable · Cool · 58 days
- French Breakfast Radish Vegetable · Cool · 28 days
- Purple Top White Globe Turnip Vegetable · Cool · 55 days
- Early White Vienna Kohlrabi Vegetable · Cool · 55 days
- American Purple Top Rutabaga Vegetable · Cool · 90 days
- American Flag Leek Vegetable · Cool · 120 days
- Sugar Snap Pea Vegetable · Cool · 62 days
- Waltham 29 Broccoli Vegetable · Cool · 74 days
- Snowball Y Cauliflower Vegetable · Cool · 70 days
- Long Island Improved Brussels Sprouts Vegetable · Cool · 100 days
- Italian Flat Leaf Parsley Herb · Shoulder · 75 days
- Bouquet Dill Herb · Shoulder · 55 days
- Common Borage Herb · Warm · 60 days
- Common Chives Herb · Cool · 80 days
- Provider Bush Bean Vegetable · Warm · 50 days
Related regional guides
- Colorado Front Range and High Plains Garden A soil-temperature-first guide for dry, variable spring conditions, fast cool-season windows, and tender crops that need reliably warm weather.
- Colorado Front Range Container Vegetable Garden CSU Extension container vegetable guide for Front Range gardeners balancing container size, water, fertility, sun, and frost timing.