Peas are a rewarding cool-weather crop, offering some of the earliest harvests in the garden before the heat of summer arrives. Successfully growing peas requires synchronizing the planting schedule with the unique climate, ensuring the plants mature during the optimal temperature window. The goal is to maximize the cool growing period while avoiding the high temperatures that cause plants to stop producing.
Optimal Timing for Spring Planting
The precise moment to plant peas in Minnesota is dictated less by the calendar date and more by the physical condition and temperature of the soil. Gardeners should aim to sow seeds as soon as the ground has thawed and is dry enough to be easily worked without compacting into mud. This window often opens in late March or early April in the southern parts of the state, though it is usually later further north.
Monitoring the soil temperature is the most accurate method for determining the proper planting time. Pea seeds can successfully germinate in soil temperatures as low as 40°F, though an ideal range for faster and more consistent germination is between 45°F and 50°F. Planting during this cooler period allows the root system to establish itself before the plant begins its rapid growth phase. Young pea plants possess a tolerance for light frost, meaning a sudden drop in temperature after planting typically poses little threat to the seedlings.
To extend the harvest period, a technique called succession planting should be employed. This involves planting small batches of seeds every ten to fourteen days after the initial sowing. Gardeners should continue this practice until about mid-May, as planting past this point risks the plants maturing during the intense summer heat, which can halt pod production when temperatures rise above 85°F. This staggered approach ensures a continuous supply of fresh peas until the cool season concludes.
Preparing the Site and Selecting Cold-Hardy Varieties
Peas perform best in well-drained soil, as standing water or heavy, saturated clay can lead to seed rot and fungal issues like root rot. Incorporating organic matter, such as well-rotted compost or manure, improves soil structure and drainage while supplying necessary nutrients.
Peas prefer a soil pH that is slightly acidic to neutral, ideally ranging between 6.0 and 7.5. While peas are legumes that fix their own nitrogen, they generally require less fertilizer than other crops, and high-nitrogen formulas should be avoided. Excessive nitrogen encourages lush, leafy growth at the expense of pod development, which defeats the purpose of the harvest.
Selecting varieties known for early maturity and cold tolerance is important for success in Minnesota’s short growing season. Shelling peas like ‘Green Arrow’ or ‘Lincoln’ are good choices; ‘Lincoln’ is also known for some heat and wilt tolerance, which is beneficial when spring quickly turns to summer. Snap peas and snow peas, such as ‘Oregon Sugar Pod II,’ are also popular, with some varieties offering resistance to common diseases like powdery mildew. When choosing, gardeners should note whether the variety is a bush type, which requires minimal support, or a vining type, which needs a structure for climbing.
Planting Techniques and Required Support
When planting, seeds should be placed 1 to 2 inches deep and approximately 2 inches apart to allow for proper air circulation and growth. This relatively close spacing is beneficial because peas often use one another for minor support even when a trellis is provided.
For gardeners planting peas for the first time in a specific location, using a commercial inoculant is a worthwhile step. This product contains beneficial bacteria, Rhizobium leguminosarum, which form symbiotic nodules on the pea roots to convert atmospheric nitrogen into a usable form. This process, called nitrogen fixation, helps the plant thrive and improves the soil for subsequent crops.
Vining pea varieties require support to prevent the plants from sprawling on the ground, which can lead to disease and rot. Trellising should be set up at the time of planting, rather than waiting until the plants are large enough to need it. Simple vertical netting, stakes, or an A-frame structure are effective solutions, providing the necessary support for the tendrils to grasp as the vines grow quickly.
Ongoing Maintenance and Harvesting
Consistent moisture is important for pea plants, particularly once they begin to flower and set pods; the soil should be kept uniformly moist but not waterlogged. Deep watering once or twice a week is preferable to light daily sprinkling, encouraging the development of deeper, more resilient roots.
Gardeners should remain watchful for common pests and diseases. The pea aphid (Acyrthsiphon pisum) is a frequent insect pest that can stunt growth and transmit viruses. Fungal diseases like Aphanomyces root rot thrive in warm, wet soil, while powdery mildew often appears later in the season in dry conditions.
To manage aphids, a strong jet of water can dislodge them, and encouraging natural predators like lady beetles helps keep populations low. Preventative measures against fungal diseases include proper crop rotation and ensuring the planting site has excellent drainage. Choosing disease-resistant seed varieties also reduces the risk of infection.
Harvesting peas at the right time ensures the sweetest flavor and encourages the plant to produce more pods. Shelling peas are ready when the pods are plump and full. Snow peas should be picked when the pods are still flat and the peas inside are barely visible, and snap peas are harvested when the pods are nearly full but remain tender and juicy. Consistent picking of mature pods signals the plant to continue flowering, extending the overall harvest period.