Borage in Zone 8A — Northern California

Borage is a fantastic addition to any Northern California garden. The delicate, cucumber-like flavor of its leaves and the beautiful, star-shaped blue flowers make it both a culinary and ornamental delight. Plus, it's a pollinator magnet, which is always a win!

Our Mediterranean climate, with its dry summers and mild winters, is generally well-suited for Borage. While we do have to contend with drought, fire season, and water restrictions, the long, 255-day growing season gives you plenty of time to get a successful crop.

If you choose to start your Borage indoors, aim to transplant it outdoors from late February through late March. This gives the seedlings a chance to establish themselves before the summer heat arrives.

Before transplanting, be sure to harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind.

When transplanting, space the Borage plants 12-18 inches apart to allow for adequate growth. Keep an eye on the weather forecast, as those late-season cold snaps can still happen.

Direct sowing is the preferred and easiest method for growing Borage here in Northern California. You can start sowing seeds directly into the garden from early March through mid September. Borage is pretty forgiving!

Choose a spot with full sun to partial shade, and prepare the soil by loosening it and amending with compost. Sow seeds about ½ inch deep and 12-18 inches apart. Keep the soil consistently moist until germination, which usually takes about a week or two.

Borage is known for self-seeding readily, so be prepared to have new plants pop up in unexpected places!

Borage needs moderate watering, especially during our dry summers. While it's a pretty easy-going plant, consistent moisture is key for healthy growth and abundant flowering.

During the cooler spring and fall months, water deeply about once a week, or when the top two inches of soil feel dry to the touch. Use the "finger test" to check the soil moisture. In the heat of summer, you might need to water every other day, or even daily, depending on your specific microclimate and water restrictions.

Water at the base of the plant to avoid wetting the foliage, which can encourage powdery mildew. Aim to give your Borage about an inch of water per week, adjusting as needed based on rainfall and temperature. Signs of underwatering include wilting leaves, while yellowing leaves can indicate overwatering. A layer of mulch around the base of the plant will help retain moisture and suppress weeds.

You can expect your first Borage harvest starting around early May, and continuing all the way through late November, thanks to our long growing season. The key is to harvest regularly to encourage continued production.

Harvest the star-shaped blue flowers when they are fully open. The young leaves are also edible and have a refreshing cucumber flavor. Simply snip off the leaves or flowers with scissors or your fingers, being careful not to damage the plant.

To prolong the harvest, deadhead spent flowers regularly. As first frost approaches in mid- November, you can let the remaining flowers go to seed to ensure a supply of new plants for the following year.

Here are a few common problems you might encounter growing Borage in Northern California:

Self-Seeding Aggressively

• What it looks like: Borage popping up in unexpected places all over your garden.
• What causes it: Borage is a prolific self-seeder, and our mild winters allow seeds to germinate easily.
• How to fix/prevent it: Deadhead spent flowers before they go to seed. If you want to control its spread, be diligent about removing unwanted seedlings. You can also grow it in containers.

Powdery Mildew

• What it looks like: A white or grayish powdery coating on the leaves and stems.
• What causes it: Powdery mildew thrives in warm days, cool nights, and moderate humidity. Surprisingly, dry leaf surfaces favor it. This can be common in some NorCal microclimates with morning fog.
• How to fix/prevent it: Improve air circulation by spacing plants adequately and pruning if needed. Remove affected leaves promptly. Neem oil or potassium bicarbonate sprays can help. A milk spray (1 part milk to 9 parts water) is a surprisingly effective organic treatment.

Can Become Leggy

• What it looks like: Tall, spindly plants with fewer leaves and flowers.
• What causes it: Insufficient sunlight or overcrowding can cause Borage to become leggy as it reaches for more light.
• How to fix/prevent it: Ensure your Borage is planted in a location that receives at least 6 hours of sunlight per day. Thin out plants to provide adequate spacing.

Northern California Specific Challenges: Our moderate-to-hot summer heat, combined with low humidity and dry-summer rainfall, can stress Borage plants if they are not properly watered. Pay close attention to watering needs, especially during heat waves.

Borage is a wonderful companion plant for many vegetables and herbs in your Northern California garden.

Good companions include tomatoes, squash, strawberries, and cucumbers. Borage attracts pollinators, which can improve fruit set in these crops. It is also believed to deter certain pests. Borage is said to improve the flavor and growth of strawberries.

There are no significant bad companions to avoid with Borage. It's a pretty easy-going plant that gets along well with most neighbors!