When to plant sweet peas in Prineville, OR

Plant sweet peas from seed, directly in the garden in Prineville, Apr 20 – May 25.

Moderate Plant seeds in the ground

Difficulty: Moderate
Sun: Full sun
Spacing: 4 to 6 inches apart along a trellis
Planting depth: 1 inch deep (soak seeds overnight first)
Frost: Handles light frost
Flowers: Blooms in early summer

Why these dates

Prineville's typical last spring frost is June 1. As a cool-season crop that handles light frost, this crop doesn't need to wait for that date. In the high desert and mountains, though, the soil usually isn't ready to work until about April 20.

High desert and mountains. Central and high eastern Oregon. Frost is possible almost any month. Use row covers, wall-o-water or cloches for warm crops, and choose short-season varieties.

How to grow sweet peas in Prineville

Prepare the bed: loosen the soil and mix in an inch or two of compost.
Plant seeds Apr 20 – May 25, 1 inch deep (soak seeds overnight first), 4 to 6 inches apart along a trellis.
Keep the soil evenly moist until sprouts appear, which can take one to three weeks in cool soil.
Harvest: Cut stems every couple of days; the more you pick, the more they bloom. Plants stop flowering once pods form.

Key numbers

55–65°FSoil to sprout
6.5–7.5Soil pH
Up to 6–8 feetClimbs
Summer heatBiggest risk

Growing notes

What makes the difference in Northwest gardens, in plain language.

Soil and sowing

Sweet peas grow deep roots and bloom best in rich, well-drained soil with plenty of compost dug in. Soak the hard seeds overnight before sowing so they take up water and sprout evenly. Slugs love the seedlings, so watch closely in cool, damp springs.

When seedlings have three or four pairs of leaves, pinch off the top. The plant responds with several strong side shoots, which means more stems and more flowers. Guide young vines onto the trellis; their tendrils grab netting easily once started.

Keep them blooming

A sweet pea plant's goal is to make seeds. As soon as a pod forms, the plant slows down flowering, so cutting flowers every couple of days, and snipping off any pods you miss, keeps buds coming. Steady watering and mulch to keep roots cool help them last into summer.

Hot weather ends the show. That's why early sowing matters: plants that bloom in the cool weeks of June have a long season before heat arrives. East of the Cascades, the window is shorter, so sow as early as the soil allows.

Common problems

Aphids cluster on new growth, and a spray of water usually handles them. Powdery mildew shows up as white powder on leaves late in the season, a sign the plants are winding down. Buds sometimes drop in cold, cloudy spells; they recover when the weather brightens.

Remember that sweet pea seeds and pods are toxic, so keep them away from children and pets, and never plant them where you grow edible peas.

Common questions

When is the last frost in Prineville, OR?

Typically June 1. In 9 years out of 10, frost is over by June 22. These are 1991–2020 NOAA climate normals for Prineville.

Is it too late to plant sweet peas in Prineville?

The spring planting window runs through May 25. Later plantings tend to struggle in summer heat.

When do sweet peas bloom?

Blooms in early summer. Cut stems every couple of days; the more you pick, the more they bloom. Plants stop flowering once pods form.

Why don't my sweet peas smell?

Fragrance depends heavily on variety. Many modern varieties were bred for large flowers and lost some scent, while old types like Cupani are very fragrant. Flowers also smell strongest on warm days.

Can I sow sweet peas in fall?

In the mildest coastal and Puget Sound gardens some gardeners do, but hard freezes can kill young plants. Late winter or very early spring sowing is more reliable in most of the Northwest.

Why are my sweet peas turning yellow and done by July?

Heat and the end of their season. Plants decline as temperatures rise and once they're allowed to form pods. Sow earlier next year, pick constantly and keep the roots cool with mulch.

Also plant in Prineville around the same time

Planting dates for sweet peas in nearby areas

Bend and Redmond, OR Apr 28 – Jun 2
Klamath Falls, OR Apr 28 – Jun 2
Burns, OR Apr 30 – Jun 4
Madras, OR Apr 20 – May 25
Lakeview, OR Apr 23 – May 28
Baker City, OR Apr 20 – May 25

Full planting calendar for Prineville · Sweet peas in every city