Eggplant in Zone 7A — Pacific Northwest

Eggplant might seem like a stretch in the Pacific Northwest, but the satisfaction of harvesting your own glossy, purple fruit is absolutely achievable. Their unique flavor and versatility in the kitchen, grilled, roasted, or in a hearty vegetable stew, make them a worthwhile addition to your garden. Plus, our cool nights actually intensify their flavor!

While our region isn't known for scorching summers, we can certainly grow eggplant successfully with a little planning. Our 183-day growing season is long enough, but you'll need to give them a head start indoors. Don't let the fear of a little extra effort deter you; the reward is well worth it.

Starting eggplant indoors is key to getting a jump on our relatively mild summers. You'll want to sow your seeds indoors in early to late March, about 8 weeks before you plan to transplant them outside. Use seed trays filled with a good seed-starting mix, and make sure to provide consistent warmth, ideally around 80-85°F. A heat mat can be really helpful here, especially with our overcast spring days.

Eggplants appreciate consistent moisture, so bottom watering your seed trays is a great way to keep the soil evenly moist without overwatering and risking damping off. Place the tray in a shallow container of water and let the soil soak it up from the bottom. Once the seedlings emerge, provide them with plenty of light. A grow light is almost essential in our region, as natural sunlight can be limited during this time of year.

Remember that our spring weather can be slow to warm up, so don't rush the process. Give those seedlings plenty of time to develop strong roots before moving them outdoors.

Transplanting your eggplant seedlings outdoors should happen in mid May through early June, once the danger of frost has passed and the soil has warmed up significantly. Before planting them directly in the ground, be sure to harden them off by gradually exposing them to outdoor conditions for about a week. This prevents transplant shock.

When transplanting, space your eggplant plants about 18-24 inches apart. Our summers, while mild, still provide enough sun for them to thrive with this spacing. Keep an eye on the weather forecast; we sometimes get unexpected cool snaps even in late spring, so be prepared to cover your young plants if needed.

Eggplants are thirsty plants, and consistent watering is essential for producing those beautiful, glossy fruits we all crave. In our dry-summer climate, you'll need to pay close attention to their moisture needs, especially during the peak of summer.

During the dry summer months, aim to water your eggplants deeply about 1-2 times per week, providing about 1-2 inches of water each time. The finger test is your best friend here: stick your finger about 2 inches deep into the soil near the base of the plant. If it feels dry, it's time to water. Watering at the base of the plant is preferable to overhead watering, as it reduces the risk of fungal diseases.

Pay attention to your plants' signals. If the leaves start to wilt or droop, they're likely underwatered. On the other hand, yellowing leaves can indicate overwatering. A good layer of mulch, like straw or wood chips, can help retain moisture in the soil and reduce the need for frequent watering.

Eggplants can produce a surprising amount of fruit, and those heavy fruits can easily cause branches to droop and even break. Providing support is a simple way to keep your plants healthy and productive.

A sturdy stake is the best option for supporting eggplant. Install the stake at planting time, placing it close to the main stem. As the plant grows, gently tie the main stem to the stake using soft twine or plant ties. This will help keep the plant upright and prevent the fruit from touching the ground, which can lead to rot.

Eggplants benefit from a little bit of pruning to encourage good air circulation and larger fruit. The pruning is minimal, but it can make a big difference in your harvest.

Throughout the growing season, remove any suckers that sprout from the base of the plant below the first main fork. These suckers will only draw energy away from fruit production. You can also limit the plant to 5-6 main branches to encourage the plant to put its energy into producing fewer, but larger, eggplants. As the first frost approaches in mid- October, you can remove any small, immature fruit to encourage the plant to focus on ripening the larger ones.

The first harvest of your eggplants will arrive mid July through early September, depending on the variety and the weather. Keep an eye on your plants and harvest the fruits when they are glossy and have a slight give when you gently press them. Dull skin indicates the eggplant is overripe and likely seedy.

When harvesting, use a sharp knife or pruners to cut the stem just above the fruit. Avoid pulling the fruit off the plant, as this can damage the branches. Regular harvesting encourages the plant to continue producing more fruit throughout the season.

As the first frost approaches in mid- October, harvest any remaining mature fruit, even if it's not quite fully ripe. They may not ripen fully off the vine, but they can still be used in cooking.

Eggplants can face a few challenges in the Pacific Northwest, but with a little vigilance, you can keep your plants healthy and productive.

• Flea Beetles
• What it looks like: Tiny round holes (shot-hole pattern) in leaves. You'll see small, dark beetles that jump when disturbed. Young seedlings are most susceptible to damage.
• What causes it: These small jumping beetles feed on leaves, especially of young plants.
• How to fix/prevent it: Row covers are your best friend for protecting seedlings during their vulnerable stage. Delay planting until plants are larger. Kaolin clay coating is effective. Neem oil spray can help. Interplant with basil or catnip. Healthy, vigorous plants often outgrow the damage.
• Colorado Potato Beetle
• Verticillium Wilt
• What it looks like: Lower leaves yellow, wilt, and die, progressing upward. One side of the plant may be affected first. You might see brown streaks in a cross-section of the stem.
• What causes it: A soil-borne fungus that can persist for years. Cooler soil temperatures favor it (unlike fusarium). It has a wide host range.
• How to fix/prevent it: Unfortunately, there's no cure. Remove infected plants immediately. Rotate crops with non-susceptible plants like corn or grains. You can try solarizing the soil. Look for resistant varieties when purchasing (they'll have a 'V' on the label).
• Blossom Drop
• What it looks like: Flowers fall off without setting fruit. Small fruit may yellow and drop. The plant looks healthy, but there's no fruit production.
• What causes it: Temperature stress is the main culprit. Eggplants don't set fruit well when nights stay above 75°F or days exceed 95°F. Low humidity, excess nitrogen, or poor pollination can also contribute.
• How to fix/prevent it: Be patient; fruit set usually resumes when temperatures moderate. Provide afternoon shade during extreme heat. Keep plants well-watered, but avoid excess nitrogen fertilizer. Try hand-pollination to ensure good fruit set.

Pacific Northwest Specific Challenges: Our mild heat and relatively dry summers (compared to other regions) can actually be beneficial for eggplants, reducing the risk of some fungal diseases. However, late blight can still be a concern, especially if you're also growing tomatoes or potatoes nearby. Good air circulation and avoiding overhead watering can help prevent it. Cool soil in spring can slow growth, so be patient and wait for the soil to warm up before transplanting. Slugs can also be a nuisance, so use your preferred slug control methods.

Companion planting can be a great way to improve the health and productivity of your eggplant. Green beans are excellent companions because they fix nitrogen in the soil, which benefits the eggplant. Peppers and tomatoes also make good companions, as they share similar growing requirements. Spinach can be planted between eggplant rows as a ground cover, helping to suppress weeds and retain moisture.

Avoid planting fennel near eggplant, as it can inhibit their growth. Fennel releases compounds into the soil that can be detrimental to many vegetable crops.