By Betty Beeman
The oldest surviving grapevine in America is almost 500 years old.
The Scuppermong vine found on Roanoke Island, North Carolina, was discovered by Florentine explorer Giovanni de Verrazzano in 1524.
Around the world today there are over 8,000 grape varieties appearing in white, red, black, blue, green, purple and golden colors. A popular grape variety for southern Arizona is Thompson seedless. The grapes are medium size and the clusters large with greenish white to golden berries. (Grapes are botanically classed as berries.)
Grapes should be planted in full sun and well-drained soils. Test for drainage by digging a hole 12 inches wide and 18 inches deep. Fill with water and let it drain. Fill it a second time and observe how long it takes for the water to drain from the hole. If the water drains out in 48 hours or less the soil has adequate drainage for growing grapes.
Grape vines can be purchased from local garden centers or big box stores in containers or bare-root. Container-grown grapes can be planted in the spring through fall. Bare-root grapes are planted during the winter months.
Regardless of the type, grapes should be planted directly in unamended soil. No organic amendments should be added at the time of planting. Just dig a hole large enough to accommodate the roots, remove any stones or caliche from the hole, loosen the soil and fill in around the roots. Bare-root plants need to be soaked in water for 4 to 6 hours after opening the package and before planting because roots tend to dry out during shipping.
Grapes can be trained to grow on trellises, arbors, single posts or fences. Google “grape trellises” or “grape arbors” for how-to information on setting up a structure.[quote_box_right]November Growing Tips
Seeds of beets, black-eyed peas, collard greens, green onions, kohlrabi, mustard and spinach can still be planted. Look on the back of the package and choose the shortest growing season for best success.
Watch weather reports for frost warnings so you can cover tender plants and trees. [/quote_box_right]
When you plant your vine, pruning begins. It is essential you prune for the health and development of the vine. Bare-root may come with one, two or more canes and leaves. Opt for the largest and most vigorous cane, pruning off all other canes and leaves. Be sure to prune close to the point of attachment on the main stem; do not leave stubs.
Prune the remaining canes back to two buds. The buds are in the nodes on the stem, the bumps on the cane where new leaves emerge.
DO NOT FEAR! Cut back to two buds only. Be careful not to slice into the bud itself. The cut should be a quarter-inch to a half-inch above the bud on a 45-degree angle across the cane.
When the vine starts to grow in the spring these two buds will produce several canes. Let them grow all year without tying them up to the trellis or doing any pruning. During the first winter, pick the strongest of the bunch and run it up the stake and tie it off with soft horticultural tape. This will become your main trunk. Cut the other ones off completely. On a container plant with multiple canes, follow the same procedure.
Vines not pruned properly soon become a tangled, underproductive jumble.
Drip irrigation works best for grapes, with two 1-gallon drip emitters placed on either side of each grape plant. Take care not to overwater the first year. Once established, water two to four times a week during growing season and fertilize with nitrogen in early spring and in the fall.
Questions for Master Gardener volunteers
Betty Beeman is a resident of Maricopa and a Pinal County Master Gardener.
This column appears in the November issue of InMaricopa.