How to Build a Simple Garden Trellis

A trellis turns a sprawling, ground-hogging plant into a vertical grower that takes up a fraction of the space and produces cleaner, healthier fruit. Cucumbers, pole beans, peas, small melons, and even indeterminate tomatoes all benefit from vertical support. Building one yourself costs under $20 in materials and takes less than an hour.

The A-Frame Trellis: Easiest to Build

An A-frame trellis leans two panels against each other to form a triangular structure.

You can grow climbing plants on both sides, effectively doubling your growing space. For each panel, you need two 6-foot lengths of 2x2 lumber ($2 each at any lumber yard) and a piece of welded wire fencing or concrete reinforcement mesh cut to 3 feet wide by 6 feet tall ($12 for a 3.5 by 7-foot sheet at home improvement stores). Staple the wire mesh to the 2x2s using 1/2-inch staples and a staple gun.

Hinge the two panels together at the top with a pair of 3-inch hinges ($4 for a pack). The A-frame opens to whatever width you want and folds flat for storage. It is self-supporting and does not need to be anchored to the ground unless you are in a windy area, in which case push two stakes through the bottom wire mesh into the soil.

The Lean-To Trellis: Best for Garden Beds Against Walls

If your garden bed runs along a fence or wall, a lean-to trellis maximizes the vertical space.

Drive two 8-foot T-posts ($5 each) or sturdy wooden stakes 18 inches into the ground at each end of the bed, positioned about 12 inches from the wall or fence. Lean them back against the structure at a 15 to 20 degree angle. Stretch galvanized wire or heavy-duty twine horizontally between the posts at 12-inch intervals, starting 12 inches from the ground. This creates a ladder-like structure that climbing plants weave through as they grow.

The angled design makes it easy to harvest from the front side and allows good air circulation behind the plants. Total cost for a 6-foot section is about $15.

String Trellis for Pole Beans and Peas

The simplest trellis for beans and peas requires only two posts and some twine. Set two sturdy posts (4x4 lumber, metal T-posts, or even thick branches) at each end of your row, buried at least 18 inches deep.

Run a horizontal wire or board across the top. From this top support, drop lengths of cotton or jute twine every 6 inches, tying them to a ground-level wire or pegging them to the soil with landscape staples. Each string becomes a climbing path for one or two plants. Cotton and jute twine are preferable to nylon because they are biodegradable. At the end of the season, cut the whole assembly down and compost the spent plants and twine together.

A 10-foot row needs about $8 in materials.

Cattle Panel Arch: The Premium Option

A cattle panel arch is the sturdiest and most productive trellis design for home gardens. A standard cattle panel is a 16-foot by 50-inch section of heavy-gauge welded wire that costs about $25 at farm supply stores like Tractor Supply. Bend it into an arch between two raised beds or over a pathway. Secure the ends by wiring them to T-posts or pushing them 6 inches into the soil of each bed. The arch creates a shaded tunnel underneath that is perfect for heat-sensitive crops like lettuce in summer while supporting heavy crops like melons and winter squash on top.

The 4-inch by 4-inch grid openings are large enough to reach through for harvesting. A single cattle panel arch lasts 15 to 20 years with no maintenance.

Materials to Avoid

Pressure-treated lumber manufactured before 2004 contains chromated copper arsenate (CCA), which leaches arsenic into soil. Modern pressure-treated wood uses copper azole or alkaline copper quaternary, which are considered safer but still not ideal for direct contact with food crops.

Untreated cedar and redwood naturally resist rot and are the best wood choices for garden structures, though they cost more. Cedar 2x2s run about $4 each compared to $2 for pine. If you use pine, apply a food-safe wood sealer or coat the soil-contact portions with raw linseed oil to extend the lifespan from 2 years to about 5 years.

Sizing Your Trellis for the Crop

Peas need only 4 to 5 feet of vertical space and lightweight support.

A few bamboo poles with twine strung between them is plenty. Pole beans climb 6 to 8 feet and need sturdier support since a full-grown bean plant loaded with pods weighs several pounds. Cucumbers reach 5 to 6 feet and need a trellis with openings no larger than 6 inches so the tendrils can grip. Small melons like cantaloupe can grow on a trellis but the fruit needs sling support once it gets larger than a softball.

Old pantyhose or mesh produce bags tied to the trellis frame cradle the fruit and prevent it from pulling off the vine under its own weight.

Positioning for Best Results

Orient your trellis on the north side of the garden bed so the climbing plants do not shade shorter crops growing nearby. If the trellis runs east to west, the south face gets the most sun. A trellis on the south or west side of a bed casts shade that can stress sun-loving plants growing in front of it. The exception is if you intentionally want afternoon shade for heat-sensitive crops. In that case, a trellis of pole beans on the west side of a lettuce bed provides welcome relief from late-day sun in midsummer. Plan your trellis placement during the garden layout phase in winter, not as an afterthought once plants are already growing.