How to Prune Grape Vines to Get Your Best Harvest

Pruning is essential to produce strong, healthy grape vines. Get expert advice on everything from how to prepare to when exactly to make your cuts. 

The botanical gift that keeps on giving, the grape vines give you fresh, delicious fruit year after year. The secret to producing the most abundant harvest: pruning. Skipping this step can prevent your vines from getting all the sunlight they need, which inhibits growth. If you're new to pruning grapevines, don't stress - it's a simple process that you only have to tackle annually. Getting familiar with the anatomy of a vine is the first step. Then all you need is a trellis, a cutting tool and your best gardening decision. The benefits (i.e. all homemade wines, jams, juice, etc.) are definitely worth it.

Vineyard Terms to Know

Before touching any of your vines, make sure you know the basic terminology. Here are the parts of the plant to add to your horticultural vocabulary:

•     Trunk: Old tree growing vertically
•     Cord: Old tree growing horizontally on the trellis
•      Arms: Old wood emerging from the cord
•     Shoots: Green shoots that started growing in the current season
•      Canes: ~1 year old tree with green shoots from the previous year and buds growing too
•     Buds: Growingfertile shoots

Understanding these terms makes it easy to break down the grapevine pruning process. Check out a few diagrams or photos online, such as those from the California Table Grape Commission.

Why Do You Need to Prune Grape Vines?

Simply put, pruning the vines ensures that the plants get enough sun. If you let your vines grow freely, the shoots and panicles will overwhelm the plant and create barriers that block out light. It's also important to get rid of older, less healthy canes and old wood to encourage new growth and avoid disease.

"We're trying to manage where the sun is and where the fruit is," says Randall Vos, an expert in commercial fruit crops at Iowa State University. "[Without pruning], the panicles won't produce as much fruit as you'd like because there are too many and there will be a big shady mess."

The vine is a perennial, meaning it comes back every year. Not cutting off shoots to limit the amount of fruit a vine produces may give you higher yields in your first year, but will harm your plant in the long run, Vos says.

Grape Pruning Tips

Pruning should be done each year during the winter or dormant season, depending on where you live (usually from January to March). It's very early fall, and even though the plants seem dormant, they're still producing sugar and nutrients, Vos explains. To prepare for pruning, use summertime to teach your vines to grow vertically in your training system (a trellis, arbor, or posts). Invest in a pair of handheld pruners or pruning shears to trim your canes. Stay away from saws (especially chainsaws). 

The buds on a vine bear a lot of fruit, but you don't need to keep them all to get a full crop. Each dormant season, when it's time to prune, choose a few of the strongest canes to leave and cut back the rest. "Usually people choose 10 to 12 good canes and shorten each to four or five buds," explains Vos.

When deciding on canes to store, look for smooth bark and dark color. The darker the color , the more cold resistant the stem tends to be . Longer canes will give you larger bunches, so if you're growing table grapes and want that standard, store-bought size, you may want to consider pruning shorter ones.

Avoid Grapevine Pruning Mistakes

The most common mistake home growers make? Vos says they don't clean enough canes. If the thought of pruning your vine aggressively causes a slight panic, remember that pruning means prosperity. It may seem contradictory, but the more growth you remove, the healthier your remaining vines will be. 

"If you drop 40 to 50 buds on an average-sized vine when fully grown, you're doing pretty well," says Vos. "You can get complicated with pruning formulas, but if you have a vigorous vine four to five years old, 40 to 50 buds should be an estimate for this to work."

Another misconception to be aware of is about the size of the cane: Remember that bigger is not better. Medium-sized canes produce the best results. Think slightly thicker than your thumb and certainly not smaller than a pencil.