As the leaves of sugar maples take on their burnished autumn hues, harvest time in Southern Ontario brings an abundance of fruit and flowers. One of my faovrite early fall images if 4-quart baskets brimming with dewy bunches of fragrant Concord grapes, usually watched over by hovering wasps.

At Toronto’s Spadina House, vines of old-fashioned Fredonia, Concord and Niagara grapes, all cultivars of the hardy North American fox grape, Vitis labrusca, are trained along two double-wire trellises, known in grape-growing as “Four-Arm Kniffin Fences”. The vines form the boundary between the orchard and the enchantingly beautiful kitchen garden behind the house. The grape trellises are maintained at a height of just under 6 feet (1.8 m), which makes pruning and harvesting easier than when grapes are grown on an overhead arbor.

For Spadina staff, keeping the grapes on the vine until they ripen is a challenge, what with hungry raccoons, squirrels, birds, and especially, light-fingered varmints of the 2-legged variety. When there’s an abundant harvest, Spadina’s kitchen uses the grapes to make jelly.

To grow grapes, you need deep, but not overly rich, well-drained soil and a sunny, southern exposure, preferably on a gentle slope. Vines planted against a south-facing wall that reflects the sun’s heat will ripen earlier. An airy site is important to discourage fungal diseases like mildew. Because grape roots can extend 12-40 feet in search of water and minerals, plant the vines where they will not have to compete with tree roots.

More than any other food crop, grapes need careful training and annual pruning to produce well. Left unpruned, vines will grow masses of foliage and long, tangled canes. Annual pruning is done in late winter to early spring. Winter pruning is best done during a thaw since frozen canes and buds are easily broken. However, spring pruning must be done before the sap runs in the vines.

The structure for Four-Arm-Kniffin training is simple. Four-by-four posts (4x4s) are driven into the ground 2-1/2 to 3 feet (75-90 cm) deep, preferably anchored in concrete or braced with a diagonal. In vineyards, posts would be set 24 feet apart, but for home-growing, you could set them every 8 to 12 feet (2.5-3.7 m). Large eyelet hooks aare screwed in at the 6-foot and 3-foot levels, then heavy-gauge galvanized wire is pulled taut to form the parallel horizontal framework to which the vine’s canes or arms will be fastened.

In our cold climate, grapes are best planted as 1-year old dormant stock in early spring. Prepare the planting hole to a depth and width of 18 inches (75 cm) and add well-rotted compost, composted manure and some damp peat moss. Mix that around well in the soil at the bottom of the hole before backfilling to the depth where the young vine will be planted. Trim the roots back to 6-8 inches (15-20 cm) and set the vine at the same level as it was in its pot, leaving 8 feet (2.5 m) between plants. Prune back the top of the plant to 2 buds. To help the vine grow upright until it reaches the first wire, insert a temporary stake into the soil and tie the vine loosely to it.

At the end of the first winter, prune back all growth to one strong cane, leaving 3-4 buds. This will be the main trunk. The objective over the next few years is to grow and prune the vine in such a way that 4 horizontal canes (arms) emerge from the trunk and are tied to the upper and lower wires. By the fourth spring, you should have four fruiting arms tied to the wires, each with 10 to 12 fruit-producing buds, as well as 4 two-bud renewal spurs. Fruit clusters should be removed until the third season to encourage grood cane growth, and suckers should be removed from the vine base.

Because pruning is such a complex topic, most good nurseries offer clear, printed instructions. And even when you master the complexities of pruning, grapes can be subject to a host of maladies: black rot fungus, which mummifies berries and turns them black; downy mildew, which attacks leaves in cool, moist weather, weakening the vine; anthracnose rot, which shows as spots on the berries; grape phylloxera; and insects which feed on the vine roots. Then there are the bees, birds, squirrels, raccoons…..

Thank goodness for 4-quart baskets!

Adapted from a column that appeared originally in the Toronto Sun

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