First Things First: Get the Right Container
Grapes need room for their vigorous growth, and you’ll need room for a trellis. Look for a container that can hold about 20 gallons, and which is at least 16 inches deep and 18 inches wide. Conversely, it’s perfectly fine to start your plants in a larger pot, as well.
- Avoid black pots or plastic pots; these get hot and may damage your plant’s roots.
- Light colored pots don’t get as hot as others.
- Stone, wood, and ceramic pots are good choices.
- Use of rolling pot stands is a good idea; you can move plants to follow the sun or avoid it if necessary.
Next, Get Healthy Cuttings
Grapes are grown from cuttings taken from established plants. Cuttings may come from dormant plants or from green, growing vines. Either way, you’re better off buying your cuttings from a reputable nursery to be sure your cuttings are healthy.
Now, Use Good Soil
Grape vines will grow in almost any soil but prefer loamy silt. However, just about any slightly acidic soil (a pH of 5 to 6 is best) with good drainage will work.
A Trellis is a Must Have
Grapes need guidance! They’ll need a support structure of some type. A trellis doesn’t need to be a complicated or expensive thing; a couple of metal or wooden stakes and some wire to string between them will work fine, as will a plain garden trellis, or even a piece of fencing.
Plant in Early Autumn
Before planting, soak the growing end of your cuttings in water for at least 12 hours, or as many as 24. Soaking your cuttings vastly improves your odds for grape-growing success.
Prepare the Pot, Too
When filling your container, place a layer of rock in the bottom for drainage, then add your soil; top with a layer of mulch. You don’t need much in the way of fertilizer for your grapes unless you know your soil is lacking in nutrients.
Proper Maintenance Matters
Let your plants grow until first frost. At this point, prune away all but the two strongest shoots or buds. Over the course of the plant’s life, you’ll want to prune annually, always removing all but the two best, one-year-old buds. This is because grapes will only grow on a two-year-old vine.
In general, growing grapes in pots is the same as growing them in the ground, but on a smaller scale.