Snow Peas in Zone 7A — Mountain West

Snow Peas are a fantastic addition to any Mountain West garden. Their crisp, sweet pods are delicious raw, stir-fried, or added to salads. Plus, they thrive in our cool spring and fall weather, and the intense sunlight really concentrates their flavor.

Our high altitude and short growing season might seem like hurdles, but Snow Peas are surprisingly adaptable. With careful timing and a little attention, you can enjoy a bountiful harvest within our 173-day growing season.

If you choose to start Snow Peas indoors, transplant them outdoors from late March through mid April. Before planting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the intense UV and temperature swings we often get.

Space transplants 3-4 inches apart. Keep an eye on the forecast — a late frost or unexpected hail can damage young plants, so be prepared to cover them if necessary.

Direct sowing is the preferred method for Snow Peas, mirroring how we often grow garden peas here. Sow seeds directly into the garden from early March through early August. For a fall harvest, aim for late July through late August.

Prepare the soil by loosening it and adding compost to improve drainage and fertility. Snow Peas prefer soil temperatures around 45-70°F for optimal germination. Plant seeds 1-2 inches deep and 3-4 inches apart. Keep the soil consistently moist until seedlings emerge.

Snow Peas need consistent moisture, especially during flowering, but they don't like soggy conditions. Because of our dry climate, you'll need to be vigilant about watering. Aim to provide about 1 inch of water per week, either through rainfall or irrigation.

Use the "finger test" to determine if your plants need water: stick your finger about 2 inches deep into the soil near the base of the plant. If the soil feels dry, it's time to water. Water at the base of the plants to avoid wetting the foliage, which can encourage disease in some conditions. However, our low humidity usually means foliar diseases aren't a huge issue.

Underwatering can lead to stunted growth and reduced pod production. Overwatering can cause root rot, especially in heavy clay soils. Signs of underwatering include wilting leaves and dry soil. Overwatering signs include yellowing leaves and constantly soggy soil. Adding a layer of mulch around your plants helps retain moisture and regulate soil temperature.

Snow Peas are vining plants and need support to grow vertically. A simple string trellis, netting, or even a section of chicken wire works well. They are lighter vines than snap peas, so you don't need anything too heavy-duty.

Install the support system at planting time to avoid disturbing the roots later. As the plants grow, gently train the vines to climb the trellis by weaving them through the support. This encourages them to grow upwards, maximizing space and air circulation.

You can expect your first harvest of Snow Peas from early May through mid October, about 55 days after planting. The key is to harvest when the pods are flat, before the peas inside fully develop. You should just barely be able to see the outlines of the peas through the pod. The pods should be crisp and translucent.

Harvest by gently snapping the pods off the vine, being careful not to damage the plant. Regular harvesting encourages continued production. As the end of the season approaches and the first frost threatens in early October, harvest all remaining pods, even if they are slightly smaller than ideal.

Here are some common problems you might encounter with Snow Peas in the Mountain West:

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems. Leaves curl, yellow, and die.
• What causes it: Various fungi that thrive in warm days, cool nights, and moderate humidity. Although our humidity is low overall, these conditions can occur occasionally.
• How to fix/prevent it: Improve air circulation through spacing and pruning. Remove affected leaves. Neem oil or potassium bicarbonate sprays help. Milk spray (1 part milk to 9 parts water) is surprisingly effective. Plant resistant varieties.

Pea Aphids

• What it looks like: Clusters of small, soft-bodied green insects on stems, leaves, and pods. Stunted growth, curled or yellowing leaves, and sticky honeydew.
• What causes it: Aphids thrive in warm weather and can quickly multiply. They suck sap from the plants, weakening them.
• How to fix/prevent it: Knock aphids off plants with a strong stream of water. Introduce beneficial insects like ladybugs and lacewings. Insecticidal soap or neem oil can be effective.

Root Rot

• What it looks like: Yellowing leaves, stunted growth, and wilting plants. Roots are brown and mushy.
• What causes it: Overwatering or poorly drained soil creates conditions favorable for fungal growth.
• How to fix/prevent it: Ensure good drainage by amending soil with compost. Avoid overwatering. Plant in raised beds if necessary.

Fusarium Wilt

• What it looks like: Wilting on one side of the plant first, then spreading. Yellow leaves starting on one side. Brown streaks in stem when cut open.
• What causes it: Soil-borne fungus (Fusarium oxysporum). Persists in soil for years. Enters through roots. Warm soil temperatures favor it.
• How to fix/prevent it: No cure once infected — remove and destroy the plant. Plant resistant varieties (look for 'F' on seed labels). Rotate crops on a 4-year cycle. Solarize soil in hot zones. Raise soil pH above 6.5.

Mountain West Specific Challenges: Our intense UV radiation can stress plants, making them more susceptible to disease. While our low humidity helps prevent some fungal diseases, the dry air can also lead to rapid soil drying. Hailstorms can also cause significant damage to young plants. Be prepared to provide shade during the hottest part of the day and protect your plants from hail with row covers or netting.

Good companions for Snow Peas include carrots, radishes, cucumbers, corn, and lettuce. Carrots and radishes loosen the soil, making it easier for pea roots to grow. Cucumbers and corn provide a natural trellis for the peas to climb. Lettuce benefits from the nitrogen fixed by the peas.

Avoid planting Snow Peas near onions and garlic, as these can inhibit their growth. Onions and garlic are allelopathic, meaning they release chemicals into the soil that can suppress the growth of other plants.