Banana Peppers in Zone 5B — Mountain West

Banana peppers are a rewarding addition to any Mountain West garden. Their mild, slightly sweet flavor and versatility in the kitchen make them a worthwhile crop, especially since the cool nights even in summer here seem to enhance their sweetness. Plus, they're just plain fun to grow.

Our short growing season and high altitude can present challenges, but with careful timing, you can definitely harvest a great crop of banana peppers. Starting seeds indoors at the right time is key to maximizing our roughly 149-day growing season and getting those peppers producing before the first frost.

Starting banana pepper seeds indoors is essential in our zone. You'll want to get those seeds going mid-March through early April, about eight weeks before you plan to transplant them outside. This gives them a head start and allows them to mature before our short season ends.

Use seed trays or small pots filled with a good seed-starting mix. Keep the soil consistently moist but not soggy, and provide plenty of warmth and light. Bottom watering is a great way to keep the seedlings happy without overwatering. A heat mat can help with germination, and once they sprout, a grow light will ensure they don't get leggy reaching for the sun. Remember, spring here starts late!

Transplanting outdoors should happen mid-May through mid-June, after the danger of frost has passed. Before planting directly into the garden, be sure to harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the intense sun and cooler nights.

Space your banana pepper plants about 18-24 inches apart in a sunny spot with well-drained soil. Even though our days can be warm, those nights can still be chilly, so a little protection with row covers initially can help them get established without stress.

Banana peppers need consistent moisture, but they don't like to be waterlogged. In our dry Mountain West climate, moderate watering is key. Since we get so little rainfall (10-20 inches annually), you'll need to be diligent.

During the hottest part of the summer, aim for about 1 inch of water per week, delivered slowly at the base of the plant to avoid wetting the foliage (low humidity means foliar issues are less common here). Use the finger test: stick your finger about 2 inches into the soil. If it feels dry, it's time to water. Since our humidity is low, overhead watering isn't as risky as in other climates, but watering at the base is still preferable.

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 will help retain moisture and regulate soil temperature.

Banana peppers are prolific plants, and the weight of all those peppers can sometimes cause the branches to droop or even break. While not strictly necessary, light staking can provide support and keep your plants upright.

Simple bamboo stakes or tomato cages work well. Install the supports at planting time to avoid disturbing the roots later. As the plant grows, gently tie the branches to the stakes with soft twine.

Pinching off the first few flowers that appear on your banana pepper plants can encourage them to focus their energy on vegetative growth early in the season. This leads to a stronger, more productive plant later on.

Throughout the season, regular harvesting is the best form of maintenance. As the first frost approaches around early October, you can remove any remaining flowers to encourage the plant to put its energy into ripening existing peppers.

You can expect your first harvest of banana peppers from late July through mid-September, about 70 days after transplanting. Look for peppers that are pale yellow-green and about 6-8 inches long. You can harvest them at any stage from yellow to red, depending on your preference.

To harvest, use sharp scissors or pruning shears to cut the pepper from the plant, leaving a short stem attached. Regular harvesting encourages the plant to continue producing more peppers. Before the first frost, harvest all remaining peppers, even if they are still green.

Green banana peppers will ripen indoors if you place them in a paper bag with a ripe apple or banana. The ethylene gas released by the fruit will help them turn yellow or red.

Even in the Mountain West, banana peppers can face some challenges. Here are a few common problems and how to address them:

Blossom Drop

• What it looks like: Flowers fall off without setting fruit. Small fruit yellows and drops. Plant looks healthy but produces no fruit.
• What causes it: Temperature stress is the main culprit. Nights above 75°F or days exceeding 95°F can prevent fruit set. Low humidity, excess nitrogen, or poor pollination can also contribute.
• How to fix/prevent it: Be patient — fruit set should resume when temperatures moderate. Provide afternoon shade during extreme heat. Keep plants well-watered but don't over-fertilize. Try hand-pollination.

Aphids

• What it looks like: Clusters of tiny soft-bodied insects (green, black, or white) on stems and leaf undersides. Sticky honeydew residue. Curled or distorted new growth.
• What causes it: Rapid-reproducing sap-sucking insects thrive in warm weather. Ant colonies may farm them for honeydew.
• How to fix/prevent it: A strong water spray can knock them off. Encourage ladybugs and lacewings (natural predators). Insecticidal soap can be used for heavy infestations. Neem oil works systemically. Avoid excess nitrogen fertilizer.

Flea Beetles

• What it looks like: Tiny round holes (shot-hole pattern) in leaves. Small dark beetles that jump when disturbed. Worst damage to young seedlings.
• What causes it: Small jumping beetles that feed on leaves. Most damaging to small, young plants.
• How to fix/prevent it: Row covers protect seedlings. Delay planting until plants are larger. Kaolin clay coating. Neem oil spray. Interplant with basil or catnip. Healthy, vigorous plants outgrow damage.

Bacterial Spot

Mountain West Specific Challenges: Our moderate-at-altitude heat, low humidity, and dry conditions can make banana peppers particularly susceptible to blossom drop during heat waves. Also, the intense UV light can stress young plants, so hardening off is extra important.

Companion planting can help your banana peppers thrive. Tomatoes make good neighbors, as they have similar needs and can provide some shade during the hottest part of the day. Basil is another great companion, as it repels pests like aphids and attracts beneficial insects. Carrots and onions can also be planted nearby, as they don't compete for the same nutrients and can help deter pests.

Avoid planting fennel or kohlrabi near your banana peppers. Fennel can inhibit the growth of many plants, and kohlrabi can attract pests that also attack peppers.