Shishito Pepper in Zone 6B — Pacific Northwest

Shishito peppers are a fantastic choice for the Pacific Northwest garden. Their mild, slightly sweet flavor with the occasional surprising kick makes them incredibly versatile in the kitchen. Plus, the satisfaction of harvesting your own peppers, even with our mild summers and cool nights, is hard to beat!

While our region presents some unique challenges for warm-season crops, like getting enough heat, starting your shishitos indoors and timing your transplant just right makes a successful harvest well within reach during our 162-day growing season. Don't let the overcast spring days discourage you!

Starting Shishito peppers indoors is the way to go here in the PNW. You'll want to sow your seeds from mid-March through early April, about eight weeks before you plan to transplant them outdoors. This gives them a head start before our cool spring soil warms up.

Use seed trays or small pots filled with a good seed-starting mix. Keep them consistently warm (around 75-80°F) with a heat mat. A sunny windowsill might not be enough light this time of year, so consider using grow lights to prevent leggy seedlings. And remember to water from the bottom to encourage strong root growth and avoid damping off in our wet springs.

Transplant your Shishito pepper seedlings outdoors from mid-May through mid-June, once the danger of frost has passed. Before transplanting, harden them off for about a week by gradually exposing them to outdoor conditions. Start with an hour or two of shade and slowly increase the time and sun exposure each day.

Plant them 18-24 inches apart in a sunny spot with well-drained soil. Even in mid-May, we can still get some cool, wet weather, so be sure to check the forecast and delay transplanting if necessary. A little row cover can help protect them from unexpected chills.

Shishito peppers need consistent moisture to thrive, but be careful not to overwater them, especially with our dry-summer conditions. During the typically dry summer months, aim for about 1 inch of water per week. Use the "finger test" – stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water.

Water deeply at the base of the plants to encourage strong root growth and avoid wetting the foliage. Overhead watering can increase the risk of fungal diseases, especially if we get an unusually humid spell. Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to yellowing leaves and root rot.

A layer of mulch around the base of the plants can help retain moisture, suppress weeds, and regulate soil temperature. Straw or wood chips work well in our region.

Shishito pepper plants are relatively compact but can sometimes lean or topple over when loaded with peppers. Providing support is optional, but it can help keep the plants upright and prevent the peppers from touching the soil.

A simple stake and some soft twine work well. Install the stake near the plant at transplant time to avoid damaging the roots later. As the plant grows, gently tie the main stem to the stake. You can also use small tomato cages for support.

Pruning Shishito peppers is fairly simple. Pinch off any early blooms that appear before the plant is well-established. This encourages the plant to focus on vegetative growth first, leading to a larger, more productive plant later in the season.

Regular harvesting is also a form of pruning. Pick the peppers frequently, even if you don't need them right away, to encourage the plant to continue producing new fruit. As we approach the first frost in early October, you can remove any remaining flowers to encourage the plant to put its energy into ripening the existing peppers.

You can expect your first harvest of Shishito peppers from mid-July through early September, about 60 days after transplanting. Look for peppers that are 3-4 inches long and still green. They should be firm and have a slightly shiny skin.

Gently twist or snip the peppers off the plant with scissors or pruning shears. Avoid pulling, which can damage the plant. Frequent harvesting encourages continuous production throughout the season.

As the first frost approaches in early October, harvest all remaining peppers, even if they are still green. You can ripen them indoors by placing them in a paper bag with a ripe banana or apple. The ethylene gas released by the fruit will help them ripen.

Here are some common problems you might encounter with Shishito peppers in the Pacific Northwest:

Aphids:

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. You might also see a sticky honeydew residue and curled or distorted new growth.
• What causes it: Aphids are sap-sucking insects that reproduce rapidly, especially in warm weather. Ant colonies may "farm" them for their honeydew.
• How to fix/prevent it: A strong spray of water can knock aphids off the plants. Encourage natural predators like ladybugs and lacewings. For heavy infestations, use insecticidal soap or neem oil. Avoid over-fertilizing with nitrogen, as this attracts aphids.

Occasional Random Hot One:

• What it looks like: Most Shishito peppers are mild, but occasionally, one will pack a surprising amount of heat. There's no visual difference between the mild and hot ones.
• What causes it: The exact reason for the occasional hot pepper is unknown, but it's thought to be related to stress factors like inconsistent watering or temperature fluctuations.
• How to fix/prevent it: Unfortunately, there's no way to guarantee that all your Shishito peppers will be mild. Consistent watering and avoiding extreme temperature swings may help reduce the chances of hot ones. Just be prepared for a surprise now and then!

Sunscald:

• What it looks like: White, papery patches on fruit exposed to direct sun. The affected areas may blister and become susceptible to rot.
• What causes it: Intense, direct sunlight on fruit, usually after leaves are removed or lost to disease, suddenly exposing previously shaded fruit. This is more common in our region if we get a sudden heat spike during our mild summers.
• How to fix/prevent it: Avoid over-pruning the foliage. Use shade cloth during periods of extreme heat. Maintain healthy foliage to naturally shade the fruit. If fruit is already exposed, drape a small piece of row cover over it.

Pacific Northwest Specific Challenges: Due to our mild summers and dry-summer conditions, Shishito peppers in the PNW are susceptible to late blight, which can quickly decimate plants. Ensure good air circulation, avoid overhead watering, and consider blight-resistant varieties. Slugs can also be a nuisance, so use traps or other control methods.

Companion planting can be beneficial for Shishito peppers in the Pacific Northwest. Tomatoes make good companions because they share similar growing requirements (sun, water, and nutrients) and can provide some shade during our mild summers. Basil is another excellent choice, as it repels many common pests and is said to improve the flavor of peppers. Carrots can help loosen the soil and improve drainage, while onions repel aphids and other insects.

Avoid planting Shishito peppers near fennel, as it inhibits the growth of many plants. Brassicas, such as cabbage and broccoli, can also be poor companions because they compete for the same nutrients and can attract pests that also affect peppers.