Narrow, shaded patches are a classic gardening dilemma, especially for food growers. Yet the determined gardener finds only room for opportunity in these apparent wastelands. Their tools of the trade are annual and perennial vining plants that make the most of vertical space, tolerate at least partial shade and -- best of all -- produce legumes, greens and other tasty veggies.
Although your options are limited when it comes to familiar annual vegetables, there are a few vining plants that tolerate shaded conditions. Pole peas (Pisum sativum) and pole green beans, shelling beans or dried beans (all Phaseolus vulgaris spp.) can produce in partial sunlight. Nasturtiums not only tolerate shade, but they also have edible leaves and flowers that add a peppery kick to salads. These flowering vines also bear seeds that can be pickled as a kind of "poor man's capers," as they're fondly known. Matrimony vine (Lycium barbarum) is a perennial shrubby vine best known for its goji berries, but the leaves are also edible and are reminiscent of watercress.
Extend your selections to less well-known vining vegetables that tolerate some shade. Perennial cucumber (Coccinia grandis "Sterile Perennial") will return every year in U.S. Department of Agriculture zones 9 and higher, but it can be grown as a part-shade annual in other parts of the country. The groundnut (Apios americana) grows throughout North America and is well-suited to wet, shady sites. Give this perennial legume a sturdy trellis or even a stout shrub to climb. Basket vine (Trichostigma octandrum) is a shade-tolerant vine that can grow as a perennial in USDA zones 10 to 12, and as an annual in USDA zones 8 and 9. Its leaves produce a spinach-like vegetable.
Degrees of Shade
If you have a range of options when it comes to shady spots, select the ones most likely to nurture vegetables. Best for most shade-tolerant vegetables is dappled shade -- the space under taller plants that allows patches of bright sun to reach plants. Second best is the kind of partial shade that gives you some hours of sunlight in the afternoon, when the sun is brightest.
Because few vining edibles flourish in deep shade, anything you can do to maximize sunlight increases yield. Paint any nearby surfaces white to reflect all available light. White or light-colored sheds, foundations, fences and retaining walls increase the intensity of the available sun, especially if they are behind the vines. In addition, consider setting down reflective mulch. Silvery, metallic mulch is especially good in shaded situations because it retains as much sunlight and heat as possible.
Consider setting up raised beds for vines if the shade you're dealing with is caused by nearby trees. Tree roots compete with vine roots for nutrients and water. For smaller vines like peas and nasturtiums, a large planter can also be used. Keep in mind, however, that some plants -- such as groundnuts -- don't need raised beds and actually thrive in the same boggy soil in which small trees or shrubs are growing.
Most vines need some kind of support structure, both to climb upon and -- in the case of shrubby perennials like matrimony vine -- to keep from taking over the rest of the space. If you already have an existing trellis, fence or even a sturdy shrub, plan to set your vining vegetables at their base. Otherwise, posts, tepees made from garden stakes, tall cages or portable trellising systems are all adequate choices, depending on the ultimate height and weight of the vine.