Pruning the vines on your trellises can ensure your plants are at their healthiest and produce more fruit.
Growing grapes in your backyard is easier than you think. According to Clark County Master Gardener John Moore, the Pacific Northwest is great territory for growing both table and wine grapes on your property.
“Technically we are the north end of the Willamette Valley and we have kind of the same conditions and they do a lot of grape growing down there and we’re doing a lot more grape growing around here,” Moore said. “This is because we have a mild winter so we don’t lose much to winter kill.”
Along with the mild winter, Moore said the grape plant thrives in the “clear and dry” summers.
“We don’t get a lot of rain (in the summer) so the fruit doesn’t get bloated,” he said. “We also have relatively low pest pressure. If the grapes are planted properly where they get good airflow and they’re the right kind of variety for the area, they don’t require a lot in the realm of fertilizer or pest spraying.”
As well as having a low pest pressure and mild summers, the Pacific Northwest and the Willamette Valley have the correct number of “heat units” and “growing degree days” needed to grow good grapes.
“We’re on the early side of the spectrum so we would not want to choose a late maturing variety (of grape) here because we may not have enough heat to make it happen,” Moore said.
Picking the right variety of grapes to grow can seem like a daunting task with different varieties, flavors and growing conditions required for different cultivars. Depending on the cultivar, grapes can be grown for wine production or just to eat. Moore recommends growing a variety of “table grapes” to eat unless you have enough property to make wine.
“A lot of grapes go into a bottle of wine,” Moore said. (For more information on grape varieties and pruning techniques, visit catalog.extension.oregonstate.edu/ec1639/html).
According to Moore, growing household table grapes is relatively simple as long as you keep the plant happy and healthy.
“I would recommend that a person choose their site first,” Moore said, explaining how with certain pruning techniques a person can grow a grape vine like a tree and does not need a bunch of property.
“A backyard grow would normally have about three to four vines, that’s a lot of grapes,” Moore said.
Moore said table grapes are also easier to grow because they are more vigorous than wine grapes, making them less susceptible to diseases while also still being able to produce enough grapes to eat, jelly, jam and freeze.
After choosing where to grow the grapes and whether or not a trellis or other growing system is needed, Moore said sun and airflow are two of the most important aspects of grape growing.
“They need good sun in the summertime and they need good airflow, otherwise mildew and other diseases will be a problem,” he said. “In order to incorporate that (airflow) we recommend growing the grapes in a North/South orientation so they get good, full sun during the summertime and air flows freely through the vines.”
Moore also said that if a person plans to grow grapes, doing a soil test is important.
“A grapevine can last 100 years or more so it’s worth doing that,” he said, “And do any amendments the soil test calls for. If you have to change something like PH, it takes a while.”
However, with the correct PH balance in the soil, a grape plant can thrive and produce for years to come.
As for planting the plant itself, Moore said to plant it in the early spring, “as soon as you can work the soil,” he said, adding gardeners should look out for diseased vines.
“Make sure you get certified vines,” he said, mentioning how gardeners can find certified grape vines through the community and Master Gardeners.
After getting the vines and seeds ready to go, Moore said to make sure the trellis or other support system planned for grape-growing is strong.
“They (the trellis system) can be simple but it needs to be strong,” he said. “These grapes can get heavy. They need to be able to support 25 to 30 pounds.”
Once the system is planted and thriving, gardeners need to make sure to keep up care of the plants by pruning and monitoring them throughout the year.
“The number one mistake about grapes is just letting them go and not doing the pruning,” Moore said. “It’s important to prune them to keep them in your yard. They will go and they create fruit on new wood and if you don’t cut that wood back every year, the fruit gets further and further away from the trunk until it’s literally in your neighbors yard.”
As well as making sure fruit is collected, Moore said it’s important to prune the canes of the plant back to ensure the plant gets proper airflow through the vines to prevent disease.
“It’s really important to cut those back to two to four canes a year and keep the new wood coming so you don’t have problems with your neighbors and get good fruit,” Moore said. He explained how pruning techniques are up to the gardener and how they want to grow their vines. He said it was important to cut each vine back to 30 buds or so each year, depending on the cultivar.
Moore himself finds backyards and the Pacific Northwest to be perfect for trying out a small grape garden.
“I think we ought to be growing more of this stuff. It’s perfect for backyards and this area,” Moore remarked.
