Sweet Peppers in Zone 10A — Southern California

Sweet peppers are a fantastic addition to any Southern California garden, offering a burst of sweetness and vibrant color to your meals. From stuffing them with rice and veggies to adding them raw to salads, their versatility shines. Plus, the satisfaction of harvesting your own sun-ripened peppers in our mild climate is hard to beat.

While we face challenges like drought and intense summer heat inland, careful planning makes growing sweet peppers here very achievable. Our long 349-day growing season gives you plenty of time to get a delicious harvest. You can start seeds indoors in late November through mid December and transplant seedlings outdoors in late January through late February.

Starting sweet pepper seeds indoors gives them a head start in our very-early spring. Begin sowing seeds indoors from late November through mid December, about eight weeks before you plan to transplant them. This timing allows the seedlings to establish well before the summer heat inland arrives.

Use seed trays or small pots filled with a good seed-starting mix. Keep the soil consistently moist, but not soggy. Bottom watering is a great way to ensure even moisture without disturbing the seeds. Place the trays in a warm spot (around 70-75°F) and provide plenty of light, either from a sunny window or a grow light.

Remember, our spring weather can be variable, so starting indoors provides a controlled environment for optimal germination and early growth.

Transplant your sweet pepper seedlings outdoors from late January through late February, once the danger of frost has passed. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun, wind, and temperature fluctuations.

Choose a sunny spot in your garden with well-drained soil. Space the plants 18-24 inches apart to allow for adequate air circulation and growth. Be mindful of unexpected temperature swings that can happen even in late winter here in SoCal.

Sweet peppers need consistent moisture to produce thick, sweet-walled fruits, but overwatering can be just as detrimental as underwatering, especially with our occasional winter rains. A good rule of thumb is to water deeply when the top two inches of soil feel dry to the touch – the "finger test."

During the cooler months, from late January through spring, you might only need to water once or twice a week, providing about 1 inch of water each time. As the weather heats up in the summer, especially inland, you'll likely need to increase watering to every other day or even daily, providing 1-2 inches of water per week. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our low-to-moderate humidity.

Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to yellowing leaves and root rot. Applying a layer of mulch around your plants will help retain soil moisture, regulate soil temperature, and suppress weeds, which is especially helpful during our hot, dry summers.

While not always necessary, providing support for your sweet pepper plants can be beneficial, especially for larger varieties that become heavy with fruit. The bush growth habit can sometimes lead to branches breaking under the weight of the peppers.

Stakes or tomato cages work well for supporting sweet pepper plants. Install the support at planting time to avoid disturbing the roots later. As the plant grows, gently tie the main stems to the stake or cage with soft twine or plant ties.

Pinching off the first few flowers that appear on your sweet pepper plants can encourage stronger root development and overall plant growth. This may seem counterintuitive, but it ultimately leads to a higher yield of peppers later in the season.

Simply pinch off the flowers as soon as they appear. Otherwise, sweet peppers don't require much pruning. As the season winds down towards late December, when our first frost usually arrives, you can remove any remaining small peppers to encourage the plant to focus its energy on ripening the larger fruits.

You can expect your first sweet pepper harvest from early April through late May, about 65 days after transplanting. Sweet peppers are ready to harvest when they've reached their full size and color for the variety you're growing. Remember, peppers will get sweeter the longer they stay on the plant.

To harvest, use pruning shears or a sharp knife to cut the pepper from the plant, leaving a short stem attached. Avoid pulling the peppers, as this can damage the plant. Regular harvesting encourages continued production.

As our first frost approaches in late December, harvest any remaining mature peppers, even if they haven't fully ripened. You can ripen them indoors by placing them in a paper bag with a ripe banana or apple.

Here are some common issues you might encounter with sweet peppers in Southern California:

Blossom Drop

• What it looks like: Flowers fall off the plant without setting fruit. Small fruit turns yellow and drops. The plant looks healthy otherwise.
• What causes it: Temperature stress is the main culprit. Sweet peppers struggle to set fruit when nighttime temperatures stay above 75°F or daytime temperatures exceed 95°F. Low humidity, excess nitrogen, and poor pollination can also contribute.
• How to fix/prevent it: Be patient – fruit set will resume when temperatures moderate. Provide afternoon shade during extreme heat inland. Keep plants consistently watered, especially during Santa Ana winds. Avoid over-fertilizing with nitrogen. Gently shake the plants to encourage pollination, or try hand-pollination.

Aphids

• What it looks like: Clusters of tiny, soft-bodied insects (green, black, or white) on stems and the undersides of leaves. Sticky honeydew residue is often present, and new growth may be curled or distorted.
• What causes it: Aphids are sap-sucking insects that reproduce rapidly, especially in warm weather. Ants may "farm" them for their honeydew.
• How to fix/prevent it: A strong spray of water from your hose can knock aphids off the plants. Encourage beneficial insects like ladybugs and lacewings to prey on them. Use insecticidal soap for heavy infestations, or neem oil for a systemic solution. Avoid excess nitrogen fertilizer, which attracts aphids.

Sunscald

• What it looks like: White, papery patches on fruits that are exposed to direct sunlight. Affected areas may blister and become susceptible to rot.
• What causes it: Intense, direct sunlight on fruit, usually after leaves have been removed or lost to disease, suddenly exposing previously shaded fruit. This is a real risk during our hot summers inland.
• How to fix/prevent it: Avoid over-pruning foliage. Use shade cloth to protect plants during periods of extreme heat. Ensure plants have healthy foliage to naturally shade the fruit. If fruit is already exposed, drape a small piece of row cover over it.

Blossom End Rot

• What it looks like: A sunken, dark brown or black, leathery patch on the bottom (blossom end) of the fruit. Often affects the first fruits of the season.
• What causes it: Calcium deficiency caused by inconsistent watering. It's not a disease but a nutrient uptake problem triggered by drought/flood cycles, which can happen even with our winter-wet rainfall.
• How to fix/prevent it: Water consistently. Mulch heavily to maintain even soil moisture. Avoid over-fertilizing with nitrogen. Remove affected fruit.

Southern California Specific Challenges: Our hot, dry summers inland, combined with periodic Santa Ana winds, can create challenging conditions for sweet peppers. Consistent watering is crucial to prevent blossom end rot and blossom drop. Shade cloth can help protect plants from sunscald during heat waves.

Companion planting can help your sweet peppers thrive in our Southern California gardens. Tomatoes make excellent companions, as they share similar growing requirements and can provide some shade during the hottest part of the day. Basil is another great choice, as it repels many common pests. Carrots and onions can also be planted nearby, as they don't compete for the same nutrients and can help deter pests. Spinach, planted as a ground cover, can help retain moisture in the soil.

Avoid planting sweet peppers near fennel, kohlrabi, or other brassicas (like broccoli or cabbage). Fennel inhibits the growth of many plants, while kohlrabi and brassicas can attract pests that also affect peppers. By choosing the right companions, you can create a thriving and productive garden.