How Deep to Bury a Trellis

Low-Lying Trellises

• T-trellises or other similarly low-lying trellises are fairly easy to construct, using two pieces of wood in the shape of a T at either end with wire running between them. This type of trellis is most commonly used for grapevines, berries or other low-growing plants such as snap peas. The timber should be buried about 2 to 3 feet. The longer you intend to keep the trellis in place, the deeper it should be buried. As the upper portion is relatively close to the ground, you do not need to worry that windy or inclement weather will push over the trellis.

Larger Overhead Trellises

• Larger trellises or overhead trellises need to be buried much deeper as their higher center of gravity makes them susceptible to damage in high winds and heavy rains. Most commonly constructed from larger wooden beams, overhead trellises should be buried 54 to 60 inches in order to provide sufficient support.

Support Posts

• If you live in a high wind area or you just want to ensure more support for your trellis, consider installing supports for the primary posts of your trellis. Place the wooden supports at a 45-degree angle against the primary posts, burying the supports to an equal depth as the primary post. If you live in a very high wind area and you are concerned about the stability of your trellis, you can bury the support posts even deeper than the main posts.

Burying in Concrete

• Depending on the size of your trellis and the type of vegetation that will be growing on it, you may not need to support your primary trellis posts with concrete. However, it is recommended that you support all of your trellis posts with concrete if the structure is intended to be more permanent, you live in an area that may experience occasional high winds, or you are planning to grow plants with heavy fruit — such as squash or melons — from your trellis. After digging a hole for your posts, pour concrete into the space. You can use concrete to support even lower-lying trellises if you think it is necessary.