Borage (Borago officinalis) is a popular annual herb, easily recognized by its vibrant blue, star-shaped flowers and slightly fuzzy leaves, which offer a delicate cucumber flavor. Gardeners value this plant for its culinary uses, medicinal properties, and appeal to pollinators like bees. Borage is straightforward to grow, making it a rewarding addition to most gardens. Timing the planting correctly is the most important factor for success with this frost-sensitive herb.
The Primary Planting Window
The best time to sow borage seeds is determined by the soil temperature, not the calendar. Since borage is intolerant of frost, planting should occur only after the last hard frost of spring has passed. Seeds require a warm environment to germinate effectively, with an optimal soil temperature range between 60°F and 70°F (15.5°C to 21°C).
Planting should occur directly into the garden bed where the plant is intended to grow permanently. Borage develops a long, delicate taproot, making it susceptible to shock and failure if transplanted. Therefore, starting seeds indoors is not recommended unless using biodegradable pots that can be planted directly into the ground. Allowing the soil to warm naturally ensures rapid germination, which typically occurs within five to fifteen days.
Preparing the Site and Seed
Successful borage growth requires proper site selection and seed placement. The plant performs best in full sun but can tolerate partial shade, especially in hotter climates. While borage tolerates average or poor soils, a well-draining medium is preferred since the plant does not thrive in waterlogged conditions.
Planting the seed requires attention to depth and spacing. Seeds should be sown about 1/4 to 1/2 inch deep and lightly covered with soil. Mature borage plants become large and bushy, requiring significant room to grow. Space plants 18 to 24 inches apart to prevent overcrowding and promote robust growth. After sowing, water the area immediately and thoroughly to settle the soil and maintain consistent moisture until germination.
Managing Self-Seeding and Succession Planting
Borage is a prolific self-seeder; once established, it often drops seeds that germinate the following season. This natural tendency can be managed or encouraged, depending on the gardener’s preference. To prevent the plant from spreading, deadhead or remove the flowers before they set seed, usually toward the end of the season.
To encourage its return, allow some of the last flowers to fade and drop their seeds naturally onto the soil. For a continuous supply of fresh leaves and flowers, succession planting is effective. This involves sowing a small batch of seeds every four to six weeks, from the initial spring planting until mid-summer. Staggering the planting ensures a fresh rotation of young, healthy plants, as older borage tends to decline in appearance and vigor as the season progresses.