Can Grapes Grow Vertically on a Deck?

Container

• To allow room for the grape's roots to spread, use a pot that is at least 16 inches deep and 16 inches wide. Because terracotta ones are porous, they lose water rapidly, meaning your grapes can dehydrate on hot days. Plastic pots make a better choice for grapes and are more durable than terracotta. Choose a light-colored container to keep the roots from overheating on sunny days.

Soil

• Plant your grape vine in soil that is loose and loamy. Rather than use soil from your garden, choose a potting soil for acid-loving plants with vermiculite or perlite mixed in. For optimal grape growth, the soil pH should be 5.0 to 5.5. To improve drainage, mix in 1 part sand to 4 parts soil, or add a 2-inch layer of packing peanuts to the bottom of the pot. Once you've planted your grapevine, mulch the soil with a layer of compost.

Support

• Your grapevine will need some type of support. To grow your grapes vertically, insert a 5- or 6-foot fan-shaped trellis into the soil. As the grapes grow, train the branches to grow along the trellis arms. If you have a deck with a railing, grow your grapes across the railing like an espalier. When the branches reach the height of your rails, tie and prune them to encourage the growth along the rails.

Grape Care

• Grapes prefer moist but not wet soil. Because the roots cannot dig deep into the soil to find water, water your containers every three days in dry weather. For grape production, do not give your vines fertilizer. Instead, add a fresh layer of compost mulch each month to feed the plants. Prune away any dead branches and any branches growing in a direction you don't want. Keep the container in an area with good air flow to discourage mildew formation.