Colorado’s short growing season means potatoes should go in the ground two to four weeks before the final frost. Knowing exactly when to plant potatoes in Colorado can make the difference between a big harvest and a disappointing one. This guide covers everything you need for success.
Potatoes are a cool-season crop. They need soil temperatures around 45-50°F to start growing well. If you plant too early, the seed pieces might rot. Too late, and the summer heat will stop tuber growth.
When To Plant Potatoes In Colorado
The best time depends on your specific location and elevation. Colorado has diverse climates, from the Front Range to the mountains and the Western Slope. Here is a breakdown by region.
Front Range (Denver, Boulder, Colorado Springs)
For most of the Front Range, the final frost happens between mid-April and early May. Plant potatoes about two to four weeks before that. This usually means:
- Lower elevations (5,000-6,000 ft): Late March to mid-April
- Higher elevations (6,000-7,000 ft): Mid-April to early May
Check your local frost dates online. The Old Farmer’s Almanac has a good tool for this.
Mountain Regions (Leadville, Breckenridge, Vail)
These areas have very short growing seasons. The final frost can be as late as June. Plant potatoes from late May to early June. You might need to use season extenders like row covers or cold frames.
Western Slope (Grand Junction, Montrose)
This region is warmer and drier. The final frost comes earlier, often in late March or early April. Plant potatoes from late March to mid-April. You can sometimes get a second crop if you plant early-maturing varieties in July.
Understanding Soil Temperature
Soil temperature is more important than the calendar date. Potatoes need soil that is at least 45°F at planting depth. Use a soil thermometer to check. Insert it 4 inches deep in the morning.
If the soil is too cold (below 40°F), the seed pieces will sit and rot. If it is too warm (above 80°F), the tubers may not form well. Aim for 50-60°F for best results.
How To Warm Soil Faster
You can speed up soil warming with a few tricks:
- Cover the planting bed with black plastic for two weeks before planting
- Use raised beds, which warm up faster than ground soil
- Add compost to improve drainage and heat retention
Choosing The Right Potato Varieties
Not all potatoes grow well in Colorado. Pick varieties that mature in 70-90 days. Here are some top choices:
- Yukon Gold: Early-maturing, good for boiling and mashing
- Red Pontiac: Reliable, stores well
- Kennebec: Great for baking and frying
- Russian Banana: Fingerling type, very flavorful
- All Blue: Fun color, good for roasting
Seed Potatoes Vs. Grocery Store Potatoes
Always use certified seed potatoes from a garden center. Grocery store potatoes are often treated with sprout inhibitors. They may also carry diseases that harm your soil. Seed potatoes are disease-free and bred for your region.
Preparing The Soil
Potatoes need loose, well-drained soil. Heavy clay soil can cause rot and misshapen tubers. Here is how to prepare:
- Test your soil pH. Potatoes prefer 5.5 to 6.5
- Add 2-3 inches of compost or aged manure
- Mix in a balanced fertilizer (10-10-10) at 1 pound per 100 square feet
- Loosen the soil to 12 inches deep
- Remove rocks and debris
Raised Beds For Better Drainage
Raised beds are ideal for Colorado gardens. They warm up faster and drain better than ground soil. Build beds at least 8 inches tall. Fill them with a mix of topsoil, compost, and sand.
How To Plant Potatoes
Follow these steps for a successful planting:
- Cut seed potatoes into pieces with 2-3 eyes each
- Let the cut pieces dry for 24-48 hours. This prevents rot
- Dig trenches 4-6 inches deep
- Space pieces 12 inches apart in rows 30 inches apart
- Cover with 4 inches of soil
- Water well after planting
Hilling Up The Potatoes
As the plants grow, you need to hill them. This means pulling soil up around the stems. It prevents sunlight from reaching the tubers. Sunlight turns them green and toxic. Hill when the plants are 6-8 inches tall. Repeat every 2-3 weeks until the plants flower.
Watering And Fertilizing
Potatoes need consistent moisture, especially during tuber formation. Water deeply once or twice a week. Aim for 1-2 inches of water per week. Drip irrigation is best because it keeps leaves dry and prevents disease.
Fertilize lightly when the plants are 6 inches tall. Use a low-nitrogen fertilizer like 5-10-10. Too much nitrogen makes lots of leaves but few tubers.
Common Watering Mistakes
- Overwatering: Causes rot and fungal diseases
- Underwatering: Leads to small, misshapen tubers
- Inconsistent watering: Causes cracking and hollow heart
Pest And Disease Management
Colorado potatoes face a few common problems. Here is how to handle them:
- Colorado potato beetle: Handpick adults and larvae. Use neem oil if needed
- Aphids: Spray with insecticidal soap
- Flea beetles: Use row covers early in the season
- Late blight: Avoid overhead watering. Remove infected plants immediately
- Scab: Keep soil pH below 6.5. Use resistant varieties
Natural Pest Control Methods
Companion planting helps. Plant potatoes near beans, corn, or marigolds. Avoid planting near tomatoes or eggplants, which share diseases.
Harvesting Potatoes
You can harvest new potatoes about 2-3 weeks after the plants flower. For full-sized potatoes, wait until the vines die back. Cut the vines 10 days before harvesting. This toughens the skins for storage.
Harvest on a dry day. Use a garden fork to gently lift the tubers. Brush off loose soil, but do not wash them. Washing removes the protective layer.
Storing Your Harvest
Store potatoes in a cool, dark, humid place. Ideal conditions are 40-50°F and 80-90% humidity. A basement or root cellar works well. Do not store them in the refrigerator. Cold temperatures turn starch into sugar, making them sweet.
Check stored potatoes regularly. Remove any that are soft or sprouting. Properly stored potatoes can last 4-6 months.
Season Extension Techniques
Colorado’s short growing season can be extended. Here are some methods:
- Row covers: Protect from frost and pests
- Cold frames: Warm the soil and air
- Mulching: Keeps soil temperature stable
- Black plastic: Warms soil faster in spring
Planting A Second Crop
In warmer areas like the Western Slope, you can plant a second crop in July. Use early-maturing varieties like Yukon Gold or Red Norland. Harvest before the first frost in October.
Common Mistakes To Avoid
Here are the biggest mistakes Colorado gardeners make:
- Planting too early in cold, wet soil
- Planting too late in hot weather
- Using grocery store potatoes
- Not hilling up the plants
- Overwatering or underwatering
- Ignoring pest problems
Signs You Planted Too Early
If the seed pieces rot, you planted too early. The soil was too cold and wet. Wait until the soil reaches 45°F. If the plants emerge and get hit by a late frost, cover them with row covers or blankets.
Frequently Asked Questions
Q: Can I plant potatoes in Colorado in July?
A: Yes, but only in warmer regions like the Western Slope. Use early-maturing varieties and plant by mid-July. Harvest before the first frost.
Q: What is the best month to plant potatoes in Colorado?
A: For most of the state, April is the best month. Adjust based on your local frost dates and elevation.
Q: How deep should I plant potatoes in Colorado?
A: Plant seed pieces 4-6 inches deep. Cover with 4 inches of soil. Hill up more soil as the plants grow.
Q: Do potatoes need full sun in Colorado?
A: Yes, potatoes need at least 6-8 hours of direct sunlight per day. Partial shade reduces yield.
Q: Can I grow potatoes in containers in Colorado?
A: Yes, containers work well. Use a 10-gallon pot or larger. Fill with loose potting soil. Follow the same planting and hilling steps.
Final Tips For Success
Planting potatoes in Colorado is not hard. The key is timing. Watch the soil temperature, not just the calendar. Use certified seed potatoes. Prepare the soil well. Water consistently. Hill up the plants. Harvest at the right time.
With these tips, you can enjoy fresh, homegrown potatoes from your Colorado garden. Start planning now. Check your local frost dates. Get your soil ready. Your future harvest will thank you.
Remember, the exact timing varies by year. A warm spring means you can plant earlier. A cold spring means you should wait. Always check the 10-day forecast before planting. If a late frost is coming, cover your plants.
Potatoes are rewarding to grow. They store well and taste better than store-bought. Give them the right start, and they will produce abundantly. Happy gardening in Colorado!