Eggplant in Zone 6B — Pacific Northwest

Eggplant, with its rich flavor and meaty texture, is a rewarding addition to any Pacific Northwest garden. Grilled, roasted, or incorporated into your favorite Mediterranean dishes, homegrown eggplant offers a taste far superior to anything you'll find at the store. Plus, those glossy, deep purple fruits are just beautiful on the plant!

While our mild summers and cool nights present a bit of a challenge for heat-loving eggplant, careful timing and a few simple tricks will help you enjoy a bountiful harvest. With our 162-day growing season, we can absolutely make eggplant work. It just needs a little extra attention.

Starting eggplant indoors is essential here in the PNW to get a jump start on our relatively short growing season. Aim to sow your seeds mid-March through early April, about 8 weeks before you plan to transplant them outdoors. This gives the seedlings plenty of time to develop a strong root system.

Use seed trays or small pots filled with a good quality seed-starting mix. Keep the soil consistently moist by watering from the bottom – set the tray in a shallow dish of water until the surface of the soil is damp. Eggplant needs warmth to germinate, so provide a heat mat or place the trays in a warm spot. Once the seedlings emerge, provide plenty of light with grow lights, especially with our overcast spring days.

Transplant your eggplant seedlings outdoors in late May through mid-June, once the danger of frost has passed and the soil has warmed up. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun, wind, and temperature fluctuations.

Choose a sunny spot with well-drained soil, spacing the plants 18-24 inches apart. Our wet springs can sometimes lead to cool soil temperatures, so consider using black plastic mulch to warm the soil before planting. This helps get your eggplant off to a good start.

Eggplant needs consistent moisture, especially during our dry summer months, to produce smooth, glossy fruit. Inconsistent watering can lead to bitter fruit and a less-than-desirable texture. You'll want to pay close attention to watering needs throughout the growing season.

During the wet springs, you may not need to water much at all, but as we transition into our dry summer, you'll need to water deeply once or twice a week. Use the finger test – stick your finger about 2 inches into the soil. If it feels dry, it's time to water. Aim to provide about 1-2 inches of water per week, adjusting based on rainfall.

Water at the base of the plants to avoid wetting the foliage, which can increase the risk of fungal diseases, even with our dry-summer humidity. Signs of underwatering include wilting leaves and dry soil, while overwatering can lead to yellowing leaves and root rot. A layer of mulch, like straw or wood chips, will help retain moisture and suppress weeds.

Eggplant branches can become heavy with fruit, causing them to bend or break. Providing support is essential to keep your plants upright and the fruit off the ground, which helps prevent rot and makes harvesting easier. A simple stake works wonders.

Install a sturdy stake near each plant at planting time, driving it deep enough into the ground to provide good support. As the plant grows, gently tie the main stem to the stake with soft twine or plant ties. Check the ties regularly and loosen them as needed to avoid constricting the stem.

Eggplant requires minimal pruning, but a little attention can improve air circulation and fruit production. Remove any suckers (small shoots) that grow below the first main fork of the plant. These suckers steal energy from the main plant and can reduce fruit size.

Throughout the season, you can also limit the plant to 5-6 main branches to encourage larger fruit. As the first frost approaches in early October, you can remove any small, immature fruit to encourage the plant to focus its energy on ripening the remaining fruit before the cold weather arrives.

You can expect your first eggplant harvest in late July through mid-September, about 70 days after transplanting. The best time to harvest is when the skin is glossy and the fruit feels firm with a slight give when pressed gently. Avoid harvesting when the skin is dull, as this indicates the fruit is overripe and may be seedy.

Use a sharp knife or pruning shears to cut the eggplant from the plant, leaving a short stem attached. Pulling the fruit can damage the plant. Regular harvesting encourages continued production throughout the season.

As the first frost approaches in early October, harvest any remaining mature fruit, even if it's not quite fully ripe. You can also try covering the plants with a blanket or row cover on frosty nights to extend the harvest a bit longer.

Here are some common problems you might encounter growing eggplant in the PNW:

Flea Beetles

• What it looks like: Tiny round holes (shot-hole pattern) in leaves. You might see small, dark beetles that jump when disturbed. The worst damage happens to young seedlings.
• What causes it: Small jumping beetles that feed on leaves. They're most damaging to small, young plants.
• How to fix/prevent it: Cover seedlings with row covers. Delay planting until plants are larger. Spray with kaolin clay or neem oil. Interplant with basil or catnip. Healthy, vigorous plants outgrow the damage.

Colorado Potato Beetle

• What it looks like: These beetles can be difficult to manage, but you can handpick them off your plants. The larvae are particularly voracious eaters.
• What causes it: The Colorado potato beetle can be a pest on eggplant, with both the larvae and adults feeding on the foliage.
• How to fix/prevent it: Handpicking is often the best solution. You can also use row covers to protect young plants.

Verticillium Wilt

• What it looks like: Lower leaves yellow, wilt, and die, progressing upward. One side of the plant may be affected first. Look for brown streaks in a stem cross-section.
• What causes it: A soil-borne fungus that persists for years. Cooler soil temperatures favor it (unlike fusarium). It has a wide host range.
• How to fix/prevent it: There's no cure – remove infected plants. Rotate with non-susceptible crops (corn, grains). Consider solarizing the soil. Plant resistant varieties (look for 'V' on labels).

Blossom Drop

• What it looks like: Flowers fall off without setting fruit. Small fruit yellows and drops. The plant looks healthy, but produces no fruit.
• What causes it: Temperature stress. Eggplant don't set fruit well when temperatures are too hot or too cold. This can also be caused by low humidity, excess nitrogen, or poor pollination.
• How to fix/prevent it: Be patient – fruit set usually resumes when temperatures moderate. Provide afternoon shade during extreme heat. Keep plants well-watered. Avoid excess nitrogen. Try hand-pollination.

Pacific Northwest Specific Challenges: The mild heat and dry-summer humidity of the Pacific Northwest can sometimes lead to blossom drop if temperatures fluctuate too much. Late blight can also be a concern in wet years, so choose blight-resistant varieties and ensure good air circulation. Slugs can be problematic, especially for young seedlings, so use slug bait or other control methods.

Good companion plants for eggplant in the Pacific Northwest include green beans, peppers, spinach, and tomatoes. Green beans fix nitrogen in the soil, which benefits eggplant. Peppers share similar growing requirements. Spinach provides ground cover and helps retain moisture. Tomatoes can act as a windbreak.

Avoid planting eggplant near fennel, as it inhibits growth. By choosing the right companions, you can create a thriving and productive garden in our unique PNW climate.