Cross-posted on Planet Green .
When most people think of gardening, they think of vegetables, not fruit—especially those who are gardening in small spaces. Who could ever fathom having a peach tree in their Brooklyn backyard, after all? It seems so…so…California. But it can be done. Fruit trees are extremely adept at growing vertically, and berry plants can fit just about anywhere. So yeah, gardening just got a whole lot sweeter, even in less tropical climates. Now all you need is a balcony, a wall, or a neglected dusty corner of your sidewalk.
R. J. Ruppenthal  is an expert in growing food with limited land access. In his book Fresh Food From Small Spaces: The Square Inch Gardener’s Guide to Year-Round Growing, Fermenting, and Sprouting  he gives great tips on how to use trellises, walls, and espaliers to maximize your harvest in minimal space:
Ruppenthal says, “Your space is limited, so you must use it well. It is normally not too difficult to keep small trees and berry bushes pruned. This involves pruning off any dead or excess growth during the winter with the aim of helping the tree maximize its energy into growing its main branches and producing good fruit. Pruning also can help promote good air circulation and sunlight for the branches. If you have a particular space that the tree must fit, you can prune most types of small trees to fit your space.”
“Growing fruit or berries on trellises,” Ruppenthal claims, “can help you train these plants vertically and maximize your space. Simple, two-dimensional trellises often are sold in nurseries and commonly take the shape of a fan or lattice. If you have a south-facing wall, consider training a fruit tree to grow two-dimensionally to maximize your space. Apples, pears, grapes, and figs are examples of plants that can be espaliered (trained and pruned to grow two-dimensionally, often into specific shapes and forms). This is fairly simple to do…
Other fruit grows better on a larger trellis. For vining fruits (such as grapes and kiwi) and cane berries (such as raspberries, blackberries, currants, and gooseberries), you will get more fruit with a three-dimensional trellis. Imagine a vineyard, where a row of grapes grows between posts. Their vines are trained along wires or horizontal supports that are strung between the posts. These must be strong enough, and widely spaced, to support heavy vines laden with fruit. Next, imagine an arbor. It is basically four posts with a stepladder placed horizontally on top of them, and perhaps some lattices on each end. Arbors make great trellises because they support three-dimensional growth: upward, across, and outward. What you need for vine or cane fruits, even in a container garden, is a smaller version of these.
Now…How-To Make a 3-D Trellis
Ruppenthal gives great tips on how to make your own trellis:
- Take four posts and string some strong fencing wire around the top corners to make a rectangular frame on top.
- Nail the posts to wooden containers or sink them into the ground or container-based soil. “Grapes and kiwis,” he says “will be trained to grow up and then along the wires, while cane berries will be planted into the soil underneath and will grow up through (inside) the rectangular wire frame.”
- Keep the canes inside the wire frame and prevent spreading—this helps the berries grow vertically, allowing maximum berry production and easy harvesting.