Colorado’s high altitude and cool nights require waiting until late spring for borage to settle in. The best time to plant borage in colorado is typically between mid-May and early June, after the last frost has passed and the soil has warmed to at least 60°F. This timing ensures your borage will thrive in Colorado’s unique climate, producing those beautiful blue star-shaped flowers that attract pollinators and add a cucumber-like flavor to salads.
Borage (Borago officinalis) is a hardy annual that can tolerate some cool weather, but Colorado’s unpredictable spring frosts can damage young plants. By waiting until late spring, you give your borage the best chance to establish strong roots before the summer heat arrives. Let’s break down exactly when and how to plant borage in Colorado for the best results.
Understanding Colorado’s Growing Zones For Borage
Colorado spans USDA hardiness zones 3 through 7, with most Front Range areas falling in zones 5 and 6. This means your last frost date can vary significantly depending on where you live. In Denver and Colorado Springs, the average last frost is around May 5 to May 15. In higher elevations like Boulder or the mountains, you might need to wait until late May or even early June.
Borage is not frost-tolerant, so you must wait until all danger of frost has passed. A light frost can kill young borage seedlings, so check your local frost dates carefully. You can find your specific zone and frost dates through the Colorado State University Extension website or your local county extension office.
How Soil Temperature Affects Borage Germination
Borage seeds germinate best when soil temperatures are between 60°F and 70°F. In Colorado, the soil warms up slowly in spring due to cool nights and occasional snow. Using a soil thermometer is a simple way to check if the ground is ready. If you plant too early in cold soil, seeds may rot or germinate poorly.
To warm the soil faster, consider using black plastic mulch or a cold frame. This can help you plant a week or two earlier if you’re eager to get started. But remember, borage grows quickly once it gets going, so waiting for the right conditions is usually better than rushing.
Best Time To Plant Borage In Colorado
The absolute best time to plant borage in Colorado is about two weeks after your last expected frost date. For most Front Range gardeners, this means planting between May 15 and June 1. For mountain gardeners, aim for late May to mid-June. This window gives the soil time to warm and reduces the risk of a late frost damaging your plants.
If you want to get a head start, you can start borage seeds indoors 3-4 weeks before your last frost. Use biodegradable pots to avoid disturbing the taproot when transplanting. Borage has a long taproot that doesn’t like being disturbed, so direct sowing is usually easier and more successful.
Direct Sowing Borage Seeds In Colorado Soil
Direct sowing is the most reliable method for planting borage in Colorado. Follow these steps for success:
- Wait until soil temperature is consistently above 60°F.
- Choose a sunny location with well-draining soil. Borage tolerates poor soil but prefers a pH of 6.0 to 7.0.
- Loosen the soil to about 6 inches deep and remove any rocks or debris.
- Sow seeds 1/4 to 1/2 inch deep, spacing them 12 to 18 inches apart.
- Water gently after planting and keep the soil moist until seeds germinate, which takes 5 to 15 days.
- Thin seedlings to 12-18 inches apart once they have two sets of true leaves.
Borage seeds need light to germinate, so don’t bury them too deep. A light covering of soil is all they need. If you’re planting in heavy clay soil common in Colorado, consider amending with compost to improve drainage.
Transplanting Borage Seedlings Outdoors
If you started seeds indoors, harden off the seedlings over 7-10 days before transplanting. Place them outside for a few hours each day, gradually increasing exposure to sun and wind. Transplant on a cloudy day or in the evening to reduce transplant shock.
Dig a hole slightly larger than the root ball, place the seedling in, and firm the soil around it. Water thoroughly after transplanting. Space plants 12-18 inches apart to allow for their bushy growth habit. Borage can reach 2-3 feet tall and wide, so give them room.
Fall Planting Considerations For Borage In Colorado
While spring is the primary planting time, some Colorado gardeners experiment with fall planting. Borage is an annual that completes its life cycle in one season, so fall planting is tricky. If you plant in late summer, borage may flower and go to seed before the first frost, but it won’t survive winter.
For a fall harvest of leaves and flowers, you can plant borage in late July or early August. This gives the plant about 60 days to mature before the first frost, which typically occurs in September or October in Colorado. However, the shorter days and cooler temperatures may reduce flower production.
If you want borage to self-seed for next year, let some plants go to flower and drop seeds. The seeds will lie dormant over winter and germinate in spring when conditions are right. This is a low-effort way to have borage return year after year.
Growing Borage In Colorado’s Unique Climate
Colorado’s high altitude means intense sunlight and low humidity. Borage actually thrives in these conditions, as long as it gets enough water. The plant’s hairy leaves help it retain moisture, but you still need to water regularly, especially during dry spells.
Here are some tips for growing borage in Colorado:
- Water deeply once or twice a week, depending on rainfall. Borage prefers consistent moisture but doesn’t like wet feet.
- Mulch around the base of plants to retain soil moisture and keep roots cool.
- Fertilize lightly if at all. Borage is a light feeder and too much nitrogen can produce lush leaves but fewer flowers.
- Deadhead spent flowers to encourage continuous blooming throughout summer.
- Watch for powdery mildew in humid conditions, though Colorado’s dry air usually prevents this.
Borage is also a fantastic companion plant for tomatoes, squash, and strawberries. It attracts bees and other pollinators, which improves fruit set in your garden. Some gardeners say borage improves the flavor of nearby tomatoes, though this is anecdotal.
Dealing With Colorado Pests And Diseases
Borage is generally pest-resistant, but Colorado gardeners may encounter a few issues. Aphids can sometimes appear on new growth. A strong spray of water from the hose usually knocks them off. Japanese beetles are rare in Colorado but can be a problem in some areas; handpick them if you see them.
Slugs and snails are more common in Colorado’s irrigated gardens. Use beer traps or diatomaceous earth around your borage plants to deter them. The hairy leaves of borage actually deter many pests, so you may not have major problems.
Root rot can occur if soil drains poorly. Amend clay soil with compost or plant borage in raised beds to improve drainage. Borage is drought-tolerant once established, so avoid overwatering.
Harvesting Borage Leaves And Flowers
You can start harvesting borage leaves once the plant has at least 6-8 leaves. Pick young, tender leaves for the best flavor. Older leaves can be tough and hairy. Use scissors to snip leaves from the outer part of the plant, leaving the inner leaves to continue growing.
Borage flowers are edible and have a mild cucumber taste. They bloom from early summer until the first frost. Pick flowers in the morning when they are fully open. Use them fresh in salads, as garnishes, or freeze them in ice cubes for a decorative touch in drinks.
To harvest seeds for replanting or culinary use, wait until the flowers fade and the seed heads turn brown. Cut the seed heads and place them in a paper bag to dry. Shake the bag to release the seeds. Store seeds in a cool, dry place for up to three years.
Common Mistakes When Planting Borage In Colorado
Even experienced gardeners make mistakes with borage. Here are the most common ones to avoid:
- Planting too early in cold soil. Wait for consistent warmth.
- Overwatering, which can cause root rot. Borage prefers moderate moisture.
- Planting in too much shade. Borage needs full sun for best growth and flowering.
- Not spacing plants enough. Crowded borage can get leggy and produce fewer flowers.
- Forgetting to deadhead. If you want continuous blooms, remove spent flowers regularly.
Another mistake is assuming borage will reseed reliably in Colorado’s climate. While it can self-seed, the seeds may not survive harsh winters in some areas. If you want borage next year, collect seeds or plant fresh ones in spring.
Frequently Asked Questions About Planting Borage In Colorado
Can I plant borage in Colorado in July?
Yes, you can plant borage in July for a late summer harvest, but you’ll have a shorter growing season before frost. Borage takes about 60 days to mature, so plant by mid-July at the latest in most Colorado areas.
Does borage need full sun in Colorado?
Borage grows best in full sun, which means at least 6 hours of direct sunlight daily. In Colorado’s high altitude, the intense sun is actually beneficial, but make sure to water adequately to prevent wilting.
How deep should I plant borage seeds in Colorado soil?
Plant borage seeds about 1/4 to 1/2 inch deep. They need some light to germinate, so don’t bury them too deep. A light covering of soil is sufficient.
Will borage survive Colorado winter?
Borage is an annual and will not survive winter in Colorado. It dies with the first hard frost. However, it may self-seed if you let some flowers go to seed before frost.
Can I grow borage in a container in Colorado?
Yes, borage grows well in containers. Use a pot at least 12 inches deep to accommodate the taproot. Place the container in full sun and water regularly, as pots dry out faster than garden soil.
Final Tips For Success With Borage In Colorado
Planting borage at the right time is crucial for success in Colorado. Remember to wait until after the last frost and when soil temperatures are warm. Direct sowing is easiest, but starting indoors can give you a head start if you’re careful with transplanting.
Once your borage is established, it’s a low-maintenance plant that rewards you with beautiful flowers and edible leaves. It’s also a magnet for bees and beneficial insects, making it a valuable addition to any Colorado garden. With proper timing and care, you’ll enjoy borage from late spring until the first fall frost.
If you’re new to gardening in Colorado, don’t be discouraged if your first attempt isn’t perfect. Borage is forgiving and grows quickly. Just pay attention to your local frost dates and soil conditions, and you’ll have a thriving patch of borage in no time.
Happy planting, and enjoy the unique flavor and beauty that borage brings to your Colorado garden.