Bell Peppers in Zone 7A — Mountain West

Bell peppers are a rewarding addition to any Mountain West garden. Their vibrant colors and crisp, sweet flavor add a burst of freshness to summer meals. Growing your own means enjoying truly flavorful peppers, far beyond what you find in the store, and they're incredibly versatile in the kitchen.

Our high altitude, intense sun, and cool nights present unique challenges, but don't let that deter you. With careful planning and attention to timing, you can absolutely grow delicious bell peppers in our short, 173-day season. Starting seeds indoors and providing proper care will set you up for success.

Starting bell pepper seeds indoors is essential for Mountain West gardeners to get a head start on our short growing season. Aim to sow your seeds in early to late March, about eight weeks before you plan to transplant them outdoors. This gives them a fighting chance.

Use seed trays or small pots filled with a good quality seed-starting mix. Keep the soil consistently moist, and a great tip is to water from the bottom to avoid disturbing the seeds. Provide warmth, ideally around 75-80°F, using a heat mat if needed. Once seedlings emerge, provide plenty of light with a grow light or a very sunny window.

Remember, spring in the Mountain West can be unpredictable, so starting indoors gives your peppers the best possible start before facing our variable weather.

Transplant your bell pepper seedlings outdoors from early May through early June, once the danger of frost has passed. Before transplanting, it's crucial to harden off your seedlings. Gradually expose them to outdoor conditions for about a week, starting with an hour or two of shade and increasing the time each day.

When transplanting, space your plants about 18-24 inches apart in a sunny spot with well-drained soil. Keep an eye on the forecast during this time – late frosts can still happen! Be prepared to cover your young plants if temperatures dip unexpectedly.

Consistent watering is key to growing plump, thick-walled bell peppers in our dry Mountain West climate. Peppers need moderate, even moisture throughout the growing season to prevent problems like blossom end rot. Since we get so little rainfall (10-20 inches annually) and humidity is low, you’ll need to be diligent.

During the hottest part of summer, aim to water deeply about 1-2 inches per week, depending on rainfall. Use the finger test – stick your finger about 2 inches into the soil. If it feels dry, it's time to water. Because of our low humidity, watering at the base of the plant is preferable to overhead watering, which can encourage foliar diseases in other regions.

Signs of underwatering include wilting leaves and blossom drop. Overwatering, on the other hand, can lead to yellowing leaves and root rot. Adding a layer of mulch, like straw or wood chips, around your plants helps retain moisture and regulate soil temperature in our intense sun.

While bell peppers have a bush-like growth habit, the weight of the fruit can sometimes cause branches to droop or even break, especially after a summer hailstorm. Providing support is an easy insurance policy.

Simple stakes work well for bell peppers. Install the stakes at planting time, placing them a few inches away from the stem. As the plant grows, gently tie the main stem to the stake with soft twine or plant ties.

This prevents toppling and keeps the fruit off the ground, reducing the risk of rot and making harvesting easier.

Pruning bell peppers in the Mountain West is all about maximizing airflow and encouraging fruit production. Start by pinching off any early flowers that appear before the plant is well-established. This directs the plant's energy towards vegetative growth, resulting in a stronger, more productive plant later on.

Throughout the season, remove any leaves or fruit that are touching the ground to prevent disease. Prune out any crowded interior branches to improve airflow and sunlight penetration. As the first frost approaches in early October, you can remove any new flowers that are unlikely to mature before the cold weather sets in.

In the Mountain West, you can expect your first bell pepper harvest from mid July through late August, about 70 days after transplanting. Bell peppers can be harvested at any stage of maturity, but the sweetest flavor comes when they're fully ripe and have turned their mature color (red, yellow, or orange).

To harvest, use sharp pruners or scissors to cut the pepper from the plant, leaving a short stem attached. Avoid pulling or twisting the fruit, as this can damage the plant. Bell peppers are continuous producers, so harvesting ripe peppers encourages the plant to set more fruit.

As the first frost approaches in early October, harvest any remaining mature peppers, even if they haven't fully colored. You can ripen green peppers indoors by placing them in a paper bag with a ripe banana or apple.

Bell peppers in the Mountain West can face a few common problems. Here's how to identify, fix, and prevent them:

Blossom End Rot

• What it looks like: Sunken, dark brown or black leathery patch on the bottom of the pepper.
• What causes it: Calcium deficiency due to inconsistent watering. Our dry climate and alkaline soil can exacerbate this.
• How to fix/prevent it: Water consistently! Mulch heavily to maintain even soil moisture. Avoid over-fertilizing with nitrogen. Remove affected fruit.

Blossom Drop

• What it looks like: Flowers fall off without setting fruit. Small fruit yellows and drops.
• What causes it: Temperature stress, especially cold nights or intense daytime heat. Low humidity can also contribute.
• How to fix/prevent it: Be patient – fruit set resumes when temperatures moderate. Provide afternoon shade during extreme heat. Keep plants well-watered.

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. Sticky honeydew residue.
• What causes it: Rapid-reproducing sap-sucking insects. Populations explode in warm weather.
• How to fix/prevent it: Strong water spray knocks them off. Encourage ladybugs. Use insecticidal soap or neem oil.

Sunscald

• What it looks like: White, papery patches on fruit exposed to direct sun.
• What causes it: Intense, direct sunlight on fruit, especially after leaf loss. Our high altitude UV makes this worse.
• How to fix/prevent it: Don't over-prune foliage. Use shade cloth in extreme heat.

Mountain West Specific Challenges: Our moderate-at-altitude heat, low humidity, and dry rainfall mean consistent watering is paramount. Be vigilant about monitoring soil moisture and providing supplemental water as needed to avoid blossom end rot and blossom drop. The intense sun can also lead to sunscald, so be mindful of providing adequate shade during the hottest part of the day.

Companion planting can give your bell peppers a boost in the Mountain West garden. Tomatoes make excellent companions, as they share similar growing requirements and can provide some shade. Basil repels pests like aphids and whiteflies, while also attracting beneficial pollinators.

Carrots help to aerate the soil, improving drainage. Onions deter pests and can help to prevent fungal diseases. Spinach acts as a ground cover, suppressing weeds and helping to retain moisture in our dry climate.

Avoid planting bell peppers near fennel, which inhibits their growth. Kohlrabi and other brassicas like cabbage and broccoli can compete for nutrients and attract pests that also affect peppers.