Peas are a cool-season annual that thrives in the mild temperatures of spring and early summer. Precise planting time is essential, as the goal is to allow the plants to mature and produce pods before temperatures rise consistently above 80°F. High heat causes the plants to stop flowering and the pods to become starchy. Timing this initial spring planting is complicated by the distinct microclimates found across Oregon’s varied landscape.
Planting Timing Across Oregon’s Major Climate Zones
The timing for sowing peas is largely dictated by the ability to work the soil. For gardeners in the Western Valleys, which includes the Willamette Valley, planting can often begin remarkably early, from late February through March. This early window is possible because peas can germinate in soil temperatures as low as 40°F, and the seedlings tolerate light frost.
Gardeners along the Coast share a similarly mild climate, but they must be especially mindful of saturated soil conditions. While the temperatures may permit a February planting, soggy ground increases the risk of seed rot and fungal issues like damping off. It is better to delay planting slightly until the soil drains sufficiently, ensuring the ground is merely moist and not waterlogged.
The climate east of the Cascade Mountains, in the High Desert and Eastern Oregon, requires a more cautious approach to planting. Due to much colder winters and the risk of hard freezes well into spring, the planting window shifts significantly later. Gardeners in these regions typically must wait until April or early May, depending on elevation, to ensure the soil is frost-free and workable. The growing season is notably shorter than in the western half of the state.
Preparing the Soil and Supporting Pea Growth
The soil needs to be well-drained and should have an optimal temperature range for germination between 50°F and 75°F. Poorly drained soil in cold conditions can lead to the seeds rotting before they sprout. Amending the area with compost before planting is beneficial.
Peas are legumes and can fix their own nitrogen from the atmosphere through a symbiotic relationship with soil bacteria. For this reason, they should be planted in soil that has low nitrogen levels, as excessive nitrogen will encourage lush foliage growth at the expense of pod production. Seeds should be sown directly into the prepared garden bed, as peas do not transplant well due to their sensitive root systems.
The seeds are planted about 1 to 2 inches deep and spaced 1 to 4 inches apart within the row. Vining varieties, which can grow several feet tall, require immediate support in the form of a trellis, netting, or a fence installed at planting time. Bush varieties are shorter and may not need support, but a small structure can help keep the plants upright and the peas clean.
Succession Planting and Fall Crops
To maximize the harvest window before summer heat arrives, growers can utilize succession planting techniques. By planting small batches of seeds every one to two weeks, starting with the initial spring planting, the harvest can be extended for several weeks. This method should continue until mid-May or early June, depending on the typical onset of summer temperatures in the specific location.
For a second, later harvest, peas can be planted again in the summer for a fall crop. This is most successful in the cooler climates of the Western Valleys and the Coast. Fall planting should occur roughly 8 to 10 weeks before the first expected hard frost date, allowing the plants to establish and produce pods during the cooler days of autumn.