How to Grow Broccoli in Colorado
Broccoli is a cool-weather crop, making it well-suited for Colorado’s climate, especially in the spring and fall. With its rich soil and abundant sunshine, Colorado provides ideal conditions for broccoli to thrive, but the state’s fluctuating temperatures and short growing season require careful planning. Here’s a comprehensive guide to growing broccoli in Colorado.
1. Choosing the Right Variety
For Colorado’s unpredictable weather, it’s essential to select broccoli varieties that are cold-tolerant and can mature within the shorter growing season. Some great varieties include:
- Arcadia: Known for its resistance to cold temperatures.
- Calabrese: A classic variety that matures quickly.
- Green Magic: Good for spring planting with heat tolerance.
2. Timing Your Planting
In Colorado, the key to successful broccoli growth is timing:
- Spring Planting: Start seeds indoors 6 to 8 weeks before the last frost date, typically around late February to March. Transplant them into the garden when they have 4-5 true leaves and temperatures are consistently above 50°F.
- Fall Planting: Begin seeds indoors in late June to July. Transplant seedlings outdoors in mid-August to early September for a fall harvest before the first frost in October.
3. Soil Preparation
Broccoli requires well-drained, fertile soil with a pH between 6.0 and 7.0. To prepare your garden:
- Amend the Soil: Incorporate compost or well-rotted manure to boost organic content and improve drainage.
- Fertilization: Use a balanced fertilizer (such as 10-10-10) before planting and continue with side dressing every 4-6 weeks to promote strong growth.
4. Planting Broccoli
Transplant your seedlings into the garden when the soil temperature is around 60°F. Space the plants about 18 inches apart in rows that are 24 inches apart. Broccoli requires full sun, so choose a location that receives at least 6 hours of sunlight per day.
5. Watering and Mulching
Colorado’s dry climate means consistent watering is crucial for broccoli:
- Water Deeply: Broccoli needs about 1 to 1.5 inches of water per week. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases.
- Mulching: Apply mulch around the plants to help retain soil moisture and regulate soil temperature.
6. Temperature Management
Broccoli prefers temperatures between 65°F and 75°F, so in Colorado’s unpredictable climate, you may need to:
- Use Row Covers: These can protect seedlings from unexpected late frosts and help cool the soil during hot spells.
- Shade Cloth: For summer months, use a shade cloth to shield plants from excessive heat, which can cause bolting (premature flowering).
7. Pest and Disease Control
Common pests in Colorado include cabbage worms, aphids, and flea beetles. To protect your plants:
- Inspect Regularly: Check under leaves for eggs and larvae.
- Use Organic Insecticides: Neem oil or insecticidal soap can be effective against pests.
- Rotate Crops: Avoid planting broccoli in the same spot every year to reduce disease risk.
8. Harvesting Broccoli
Broccoli heads are ready to harvest when they’re compact and deep green. Cut the central head with a sharp knife, leaving the side shoots intact. With proper care, your plants will produce smaller side heads throughout the growing season.
By following these steps, you’ll be able to grow healthy, productive broccoli in Colorado’s unique climate.
