When To Plant Bell Peppers In Washington State

Getting your bell pepper timing right is the single biggest factor for a great harvest here in Washington. If you’re wondering when to plant bell peppers in Washington State, you need to plan around our unique and often unpredictable climate.

Our short growing season and cool springs mean you can’t just follow generic advice. This guide will walk you through the exact timing, from starting seeds indoors to moving plants outside, so you can give your peppers the best possible start.

This is your core calendar. Bell peppers need warm soil and no threat of frost, which pushes our planting dates later than many other regions.

Understanding Your Washington Growing Zone

Washington’s climate varies dramatically from west to east. Your USDA Hardiness Zone is your best starting point.

Western Washington (Zones 8a-9a): This includes the Puget Sound area and coastal regions. You have milder winters but cooler, wetter springs. The last frost is typically between mid-April and early May.
Eastern Washington (Zones 5b-7a): This area, like Spokane and the Tri-Cities, has hotter summers but colder winters and a shorter season. The last frost can be as late as mid-May.

Always check your local frost dates. Your county extension service is a fantastic resource for hyper-local advice.

Starting Bell Pepper Seeds Indoors

Because of our short season, starting seeds indoors is non-negotiable for bell peppers. They need a long head start.

When to Start: Begin seeds 8-10 weeks before your last expected frost date. For most of Western WA, start seeds in early to mid-March. For Eastern WA, aim for late March to early April.
How to Start: Use a sterile seed-starting mix in small pots or trays. Plant seeds ¼ inch deep. They need warmth to germinate—a heat mat set to 80°F is ideal. Keep the soil moist but not soggy.
After Germination: Once sprouts appear, move them to a very sunny south-facing window or under grow lights for 14-16 hours a day. Thin to one strong seedling per pot.

Transplanting Seedlings Outdoors

Rushing this step is the most common mistake. Bell peppers are tropical plants and hate the cold.

Critical Soil Temperature: Wait until the garden soil is consistently at least 65°F. This is often 2-3 weeks after your last frost date. Use a soil thermometer to be sure.
Typical Outdoor Planting Window:
- Western WA: Late May to early June.
- Eastern WA: Early to mid-June.
Hardening Off is Essential: For 7-10 days before transplanting, gradually acclimate your seedlings to outdoor conditions. Start with just an hour in a shaded, sheltered spot, increasing their time and sun exposure each day.

Preparing Your Garden Bed

Bell peppers thrive in specific conditions. A little prep work makes a huge difference.

Sunlight: Choose the sunniest spot in your garden—at least 8 hours of direct sun daily.
Soil: They need well-draining, fertile soil. Work in several inches of compost or well-rotted manure a few weeks before planting. Raised beds are excellent for warming up faster in our cool springs.
Fertilizer: Mix in a balanced, slow-release organic fertilizer at planting time. Avoid high-nitrogen mixes, which will give you lots of leaves but few fruits.

Step-by-Step Planting Guide

On a cloudy afternoon or calm evening, dig a hole slightly larger than the root ball of your seedling.
Gently remove the plant, teasing apart any circling roots if it’s root-bound.
Place it in the hole, planting it slightly deeper than it was in its pot. This helps support the stem.
Space plants 18-24 inches apart in rows 24-36 inches apart for good air flow.
Water deeply immediately after planting to settle the soil.

Caring for Your Bell Pepper Plants

Consistent care through the summer is key to getting those thick-walled, sweet peppers.

Watering and Mulching

Peppers like consistent moisture, but wet feet cause rot. Water deeply when the top inch of soil is dry. Drip irrigation or soaker hoses are best to keep leaves dry and prevent disease. Apply a 2-3 inch layer of straw or shredded bark mulch to conserve moisture, suppress weeds, and keep soil warm.

Feeding and Support

Once plants begin to flower, feed them with a fertilizer higher in phosphorus and potassium (like a 5-10-10 formula) to encourage fruiting. Most bell pepper varieties benefit from a small cage or stake for support, especially once heavy fruits start to develope.

Managing Washington’s Cool Nights

Our summer nights can still be chilly, which can slow pepper growth. Using floating row covers or even placing water jugs around plants can help trap daytime heat. Black plastic mulch can also warm the soil effectively.

Common Problems and Solutions

Blossom End Rot: A dark, sunken spot on the fruit bottom is caused by calcium deficiency, usually due to irregular watering. Maintain even soil moisture and ensure your soil pH is around 6.5-6.8.
Poor Fruit Set: If flowers drop without making fruit, it’s often due to nighttime temps below 55°F or above 90°F. Be patient for warmer weather, and avoid over-fertilizing.
Pests: Watch for aphids and flea beetles. A strong spray of water or insecticidal soap usually manages them. Good spacing helps prevent disease.

Harvesting Your Bounty

Bell peppers can be harvested at any size, but they are sweeter when fully mature. Green peppers are immature; if left on the plant, they will turn red, yellow, orange, or purple (depending on the variety). This change adds sweetness but takes more time. Use pruners or a sharp knife to cut the fruit from the plant, leaving a short stem attached.

FAQ: Growing Bell Peppers in Washington

Can I plant bell peppers directly in the ground in Washington?

It is not recommended. Our growing season is too short for direct-sown seeds to mature fully. Starting indoors is crucial for success.

What are the best bell pepper varieties for Washington’s climate?

Choose varieties with shorter “days to maturity” (70-80 days). Good options include ‘Ace’, ‘King of the North’, ‘California Wonder’, and ‘Gypsy’.

Should I use walls of water or cloches?

Absolutely. These season-extending tools are very helpful in Washington. They protect young plants from wind and trap heat, letting you transplant a week or two earlier safely.

My plants are growing but not producing peppers. Why?

This is usually a temperature issue. Cool nights below 55°F or very hot days above 90°F can cause blossom drop. Ensure they are getting enough sun and that you are not using too much nitrogen fertilizer.

By following this schedule and tips, you can grow a productive bell pepper crop even in Washington’s challenging climate. The key is patience—waiting for truly warm soil and protecting plants from our cool nights. With the right timing, you’ll be harvesting crisp, sweet peppers from your own garden all summer long.