Bell Peppers in Zone 6B — Mountain West

Bell peppers are a rewarding crop for the Mountain West gardener. Their sweet flavor and crisp texture, especially intensified by our cool nights even in summer, make them a versatile addition to your kitchen. Plus, there's a certain satisfaction in harvesting colorful peppers you’ve grown yourself, despite our challenging high altitude gardening conditions.

Our short season and intense sun can seem daunting, but with careful timing and a few tricks, you can absolutely enjoy a bountiful bell pepper harvest. We have a 163-day growing season here, so starting indoors is key.

Starting bell pepper seeds indoors in early to late March gives them a head start on our short growing season. Aim for about 8 weeks before you plan to transplant them outdoors.

Use seed trays or small pots filled with a good seed-starting mix. Keep the soil consistently moist, and bottom watering is a great way to avoid damping off. Provide warmth (a heat mat helps) and plenty of light – a grow light is essential, especially with our late spring character here.

Transplant your bell pepper seedlings outdoors from early May through early June, once the danger of frost has passed. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week.

Space plants 18-24 inches apart in a sunny spot with well-drained soil. Keep an eye on the weather forecast – a late frost can still happen, so be ready to cover your young plants if needed.

Consistent moisture is crucial for bell peppers in our dry Mountain West climate. Inconsistent watering leads to blossom end rot and thin-walled fruit, problems we want to avoid.

During the peak of summer, when temperatures are around 85°F, aim to water deeply about 2 inches per week, depending on rainfall. Use the "finger test" to check soil moisture – stick your finger about 2 inches into the soil; if it feels dry, it's time to water. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases, although our low humidity minimizes this risk.

Signs of underwatering include wilting leaves and blossom drop. Overwatering can cause yellowing leaves and root rot. Mulching around your plants with straw or wood chips helps retain moisture and regulate soil temperature, a valuable trick in our intense sun and dry conditions.

While bell peppers have a bush-like growth habit, the weight of the fruit can cause branches to droop or even break. Providing support is a good idea, especially as your plants mature.

Simple stakes are often sufficient. Insert the stake near the plant at planting time to avoid damaging the roots later. As the plant grows, gently tie the main stem to the stake with soft twine or plant ties. This prevents toppling, particularly when loaded with fruit.

Pruning bell peppers can improve airflow and encourage fruit production. Pinch off any early flowers that appear before the plant is well-established – this directs the plant's energy into vegetative growth.

Remove any fruit that touches the ground to prevent rot. You can also prune out some of the interior branches to improve air circulation and reduce the risk of disease. As the end of the season approaches (early October in the Mountain West), remove any new flowers to encourage the remaining fruit to ripen before frost.

You can expect your first bell pepper harvest from mid July through early September, about 70 days after transplanting. Bell peppers can be harvested green at the immature stage, but they develop their sweetest flavor and full color (red, yellow, or orange) when fully ripe.

The pepper should feel firm and have a glossy skin. Use pruning shears or a sharp knife to cut the pepper from the plant, leaving a short stem attached. Regular harvesting encourages continued production. As the first frost approaches, harvest any remaining peppers, even if they are still green – they can ripen indoors in a paper bag.

Here are common bell pepper problems in the Mountain West:

Blossom End Rot

• What it looks like: Sunken, dark brown or black leathery patch on the bottom of the fruit.
• What causes it: Calcium deficiency caused by inconsistent watering. Our dry climate with sporadic rainfall makes this a common issue.
• How to fix/prevent it: Water consistently, especially during fruit development. Mulch heavily. 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, often due to cold nights or even a few days of unexpected heat. Also caused by low humidity, excess nitrogen, or poor pollination.
• 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 insects on stems and leaf undersides. Sticky honeydew residue.
• What causes it: Rapid-reproducing sap-sucking insects that thrive in warm weather.
• How to fix/prevent it: Strong water spray knocks them off. Encourage natural predators like 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, which is common at our high altitude.
• How to fix/prevent it: Don't over-prune foliage. Use shade cloth in extreme heat.

Mountain West Specific Challenges: Our high altitude, intense UV, low humidity, and dry rainfall combine to make consistent watering and sun protection critical for bell peppers. Mulch is your friend!

Companion planting can help your bell peppers thrive in the Mountain West.

Good companions:

• Tomatoes: They enjoy similar growing conditions and can offer mutual support.
• Basil: Repels pests like aphids and whiteflies, and is said to improve pepper flavor.
• Carrots: Their roots loosen the soil and attract beneficial insects.
• Onions: Repel pests and deter fungal diseases.
• Spinach: Provides ground cover, suppressing weeds and conserving moisture.

Bad companions:

• Fennel: Inhibits the growth of many plants, including bell peppers.
• Kohlrabi: Competes for nutrients and space.
• Brassicas (cabbage, broccoli, cauliflower): Attract pests that can also affect bell peppers.