Pea plants are vining crops that require external support to grow upright and maximize production. Installing a trellis elevates the foliage, which improves air circulation and reduces humidity, lowering the risk of fungal diseases like powdery mildew. Vertical growth also keeps developing pods off the soil, preventing rot and making the crop easier to spot and harvest. Providing the correct structure is foundational for a successful, high-yielding pea season.
Defining Pea Varieties and Required Heights
The appropriate height for a pea trellis depends entirely on the specific variety being cultivated and its mature growth habit. Vining or climbing peas, including popular shelling and sugar snap varieties, are indeterminate growers that reach considerable heights. For these vigorous cultivars, a trellis must be constructed six to eight feet tall; some heirloom types may even climb to ten feet, necessitating a sturdy and tall structure.
Snow peas have an intermediate growth pattern, often maturing in the four-to-six-foot range, making a mid-sized trellis suitable. Bush or dwarf pea varieties are determinate plants that stop growing once flowering begins, usually topping out between 18 and 30 inches tall. While these shorter plants may not require a full trellis, a short fence or staking two to three feet high helps lift the stems for better harvest access and airflow. Always consult the mature height specification printed on the seed packet to determine the necessary trellis height.
Structural Considerations for Pea Trellis Design
Once the required height is known, the trellis design must focus on stability to support the substantial weight of the mature vines and pods. For any structure exceeding six feet, anchoring the vertical supports is important, as the dense foliage acts like a sail and can catch the wind, causing collapse. End posts should be driven deep into the soil or set in concrete to provide a strong footing against lateral forces.
Various materials can be used for the climbing surface, including nylon netting, heavy-duty twine, cattle panels, or wire mesh fencing. Netting must be tensioned tightly between robust posts to prevent sagging under the load. Teepee or pyramid-style trellises, often made from bamboo poles, provide greater stability due to their angled geometry and are practical for smaller plantings. When planting, arranging the peas in a double row with the trellis positioned directly between them, spaced about six inches apart, maximizes the growing area and yield per square foot.
Techniques for Training Pea Vines
Pea plants use specialized, thread-like structures called tendrils to climb. These tendrils instinctively coil around any slender support material they encounter. Initial guidance is often required to ensure the young plants begin utilizing the trellis instead of sprawling on the ground or tangling with neighboring plants.
Training should begin when the pea vines are only four to six inches tall, before the tendrils have fully developed and interlocked. Simply positioning the growing tips of the young plants so they make contact with the trellis material is often enough to initiate the climbing process. If the tendrils are not immediately finding the support, a gardener can gently loop the vine around a section of the mesh or loosely tie the stem to the structure using soft garden twine. Continuous, upward growth is sustained by the plant itself, but occasional checks are beneficial to redirect any stray vines that have fallen away from the support back onto the trellis.