Many different types of trellis systems have been designed for growing vegetables, but most tend to fall into three main categories. A flat vegetable trellis is usually flat on the surface and can extend upward as high as is needed, depending on the type of vegetable being grown. Caged trellises are usually multi-sided, most commonly in the shape of a pyramid or a cone. Pole trellising is also commonly used for a wide variety of vegetables, and is probably the most easy to install.
A flat vegetable trellis is commonly used for peas, squash, and cucumbers. It is ideal for heavier vegetables because these trellises can be made in various widths and heights, and can be installed against walls to help give them more support. This type of trellis is usually constructed of overlapping wood, which adds to their ability to bear extra weight. Most gardeners recommend burying the trellis to a depth that will best offset its height. Ideally, the trellis should be buried at least 24 inches (61 cm) into the garden bed.
Tomatoes and peppers are commonly grown using a caged vegetable trellis. Cages are sometimes constructed entirely of wire mesh, but can also be made from wood. Mesh cages are usually circular or cone shaped, and are installed around each individual plant. Most gardeners claim that vine type plants that are trellised usually produce more yield than plants allowed to grow along the ground. In addition, trellising the plants helps protect them from rot and some types of insect infestation.
Many types of beans benefit from being staked. This type of trellising encourages the bean plant to wrap around a stake or pole as it grows. Beans that grow along a pole are considered much easier to harvest compared to beans allowed to form a bush or beans that grow along the ground. Bean plants often produce a great many leaves, which can make it difficult to spot the bean itself. Having them staked makes the beans more visible, and eliminates the need for constant bending while harvesting.
Adding a vegetable trellis to a garden is not considered difficult. The extra time it takes is usually offset by the amount of time the trellis may save in tending and harvesting. In addition, trellising often produces larger, more uniform vegetables. Trellises specifically designed for different types of plants can usually be purchased at nurseries or home improvement retailers, though some gardeners prefer to build their own.