When To Plant Peppers In Washington State

Getting your pepper timing right is the single biggest factor for a great harvest. If you’re wondering when to plant peppers in Washington State, you’re already on the right track. Our unique climate, with its cool springs and relatively short growing season, means timing is everything. Plant too early, and a late frost can wipe out your seedlings. Plant too late, and your peppers won’t have enough warm days to ripen fully. This guide will walk you through the exact schedule and methods for success.

This is your core calendar. The key is to start peppers indoors and transplant them outside only after the weather has truly settled. Peppers are tropical plants that demand warmth from seed to harvest.

Understanding Your Washington Growing Zone

Washington’s climate varies dramatically from west to east. Your specific zone is your best guide.

Western Washington (Zones 8a-9a): This includes Seattle, Tacoma, and Olympia. It has milder, wetter winters and cooler summers. The last spring frost is typically between April 15th and May 1st.
Eastern Washington (Zones 5b-7a): This includes Spokane, Tri-Cities, and Yakima. It has colder winters, hotter summers, and less rainfall. The last frost date can range from late April to mid-May, depending on elevation.
Coastal Areas (Zones 8b-9a): These areas frost rarely but have cooler summer temperatures, which can slow pepper growth.

Always check your local last frost date. Your county extension service is a fantastic resource for this.

The Indoor Seed Starting Schedule

Starting seeds indoors is non-negotiable for peppers in Washington. It gives them a crucial head start.

Start seeds 8-10 weeks before your last expected frost date. For Western WA, this is late February to early March. For Eastern WA, aim for mid-March.
Use a sterile seed-starting mix and plant seeds 1/4 inch deep.
Provide bottom heat. A seedling heat mat set to 80°F dramatically improves germination.
Once sprouted, provide 14-16 hours of strong light daily using grow lights placed just a few inches above the plants.

Pepper seedlings grow slower than tomatoes, so don’t get discouraged if they seem small for a while. Their growth will accelerate as days get longer.

The Outdoor Transplanting Timeline

Patience here pays off. Peppers are extremely sensitive to cold soil and air.

Critical Rule: Transplant peppers outdoors 2-3 weeks after your last frost date. For many, this means late May or even early June.
Soil Temperature Must Be Above 60°F. Use a soil thermometer. Cold soil will stunt plants for the entire season.
Watch the nightime forcast. Consistently warm nights above 50°F are the real signal.

Rushing this step is the most common mistake gardeners here make. It’s better to have a slightly pot-bound plant inside than a dead one outside.

Preparing Your Garden Bed

Peppers need a warm, sunny, and nutrient-rich home.

Site Selection

Choose the sunniest spot in your garden—at least 8 hours of direct sun. A south-facing slope or against a heat-absorbing wall (like a house or fence) is ideal, especially in cooler western areas.

Soil Preparation

Washington soils often need amending. Here’s what to do:

Test Your Soil: A simple test can reveal pH and nutrient levels. Peppers prefer a pH of 6.0-6.8.
Add Compost: Work in 2-3 inches of well-rotted compost to improve drainage and fertility.
Consider Warmth: Using black plastic mulch or red plastic mulch (shown to benefit peppers) warms the soil faster. Lay it down a week before planting.

Hardening Off Your Pepper Plants

This 7-10 day process acclimates your tender seedlings to outdoor conditions. Skipping it causes shock and sunscald.

Days 1-3: Place plants in a shaded, protected spot outside for just 2-3 hours.
Days 4-6: Gradually increase their time outside to 6 hours, introducing a bit of morning sun.
Days 7-10: Leave them out all day and night, provided temperatures stay above 50°F. Ensure they are watered.

After this, they’re ready for their permanent spot. If a surprise cold night is forcasted, bring them back inside or cover them.

Planting and Seasonal Care Tips

Once in the ground, your focus shifts to consistent care.

Planting Technique

Space plants 18-24 inches apart in rows 24-36 inches apart.
Plant at the same depth they were in their pot. Unlike tomatoes, peppers do not root from their stems.
Water in thoroughly with a starter fertilizer or fish emulsion.

Watering and Feeding

Consistent moisture is key, especially during fruit set.

Water deeply 1-2 times per week, aiming at the base. Drip irrigation is best.
Mulch with straw or grass clippings to conserve moisture and suppress weeds.
Feed with a balanced fertilizer or one slightly higher in phosphorus when first flowers appear.

Extending the Season

Washington’s early fall frosts can cut the harvest short. Be prepared.

Floating Row Covers: Keep these handy to drape over plants on chilly nights in early fall.
Container Growing: Growing peppers in pots allows you to move them to a sheltered porch or garage when cold weather threatens.
If a hard frost is predicted and you still have green fruit, you can pull the entire plant and hang it upside down in a garage; many peppers will continue to ripen.

Recommended Pepper Varieties for Washington

Choosing varieties with shorter “days to maturity” increases your success.

Early Bell Peppers: ‘Ace’, ‘King of the North’, ‘Gypsy’ (matures in ~60 days).
Productive Jalapeños: ‘Early Jalapeño’, ‘Jalafuego’.
Cool-Climate Specials: ‘Hungarian Wax’ (banana pepper), ‘Shishito’.
For Hot Summers (Eastern WA): You can try longer-season varieties like ‘Carmen’ or ‘Habanero’ if started very early indoors.

Frequently Asked Questions (FAQ)

Can I plant pepper seeds directly in the garden in Washington?
It is not recommended. Our soil warms too slowly, and the growing season is too short for direct-sown peppers to mature.

What is the latest I can plant peppers?
Aim to have transplants in the ground by mid-June at the absolute latest. Later planting risks the fruit not maturing before fall cool-down.

Why are my pepper plants growing but not producing fruit?
Temperatures below 60°F or above 90°F can cause blossoms to drop. Also, excess nitrogen fertilizer promotes leaves, not fruit. Ensure they are getting enough sun and try a blossom-set spray if cool weather persists during flowering.

Should I prune my pepper plants?
In Washington, minimal pruning is best. Removing the very first flowers can encourage the plant to grow larger before setting fruit. Some gardeners pinch back leggy seedlings to encourage bushiness.

How do I know when my peppers are ready to harvest?
Most peppers can be harvested green when they reach full size. For colored (red, orange, yellow) varieties, they will change color on the plant. Use pruning shears to cut the fruit off, don’t pull, to avoid damaging the branch.