Building a trellis can be as simple or complicated as you choose to make it. More complex ones are large and can run the length of a long fence. Simple ones can be only a foot or so wide and a couple of feet high.
A trellis is basically a two-dimensional grid, most often made out of wood but sometimes PVC, that acts as a plant support. Here are some things to consider to help you figure out how much work is involved in building the type of trellis you'd like.
The Size and Style of the Trellis
The larger the size and the more complex the style, the more money and time it's going to take to build. Begin by deciding how expansive and creative you'd like your design to be.
Some suggestions are to grow a grape vine, cucumbers, or climbing roses, but there are plenty of plants of different kinds that will be happy to climb a trellis, from vegetables to flowering creepers.
Find the desired location and measure the dimensions to get a sense of what you'll be able to fit there.
The Type of Material
Cheap wood elements like bamboo or pine poles are common go-tos. Although not as common, PVC is also an option. PVC tends to be more expensive initially and requires special tools to cut and assemble.
Hard woods like oak or cedar may cost more, but they're also more weather resistant and will typically last longer.
Take your calculated dimensions to your lumber store to price out your plans. Don't forget to include the costs of all necessary fasteners.
Most trellises have a lattice. Pre-made lattices tend to cost less, but may not fit a custom size. If you choose to make a trellis from scratch, be prepared to spend a little more time and money. Picking up some extra wood is also a good idea in case of errors.
A building sketch becomes more important the more complicated the design. Plans also help with estimating the space, time and cost.
To make sure you get the structural support you need, think ahead about the types of plants you'd like on the trellis. Go to a garden center to find out the cost of these plants and how many you'd need for the type of trellis you're building.