How to Use Grow Bags for Amazing Vegetable Gardens
Yes, these bags are lightweight and portable, but that’s not all. An Ohio extension agent explains another surprising perk.
After years of hauling heavy clay and ceramic pots out of storage each spring, Mike Hogan has become a big fan of grow bags. "They're nothing more than a container," he says "just cheaper, lighter, easier to store and—more breathable to promote stronger roots and happier plants." Hogan is an extension educator with The Ohio State University and teaches gardeners how to use this popular new gardening product.
The breathability benefit is a bit unexpected to most, says Hogan, as he explains the botanical benefits inside the bags. In typical clay and plastic pots, plants grow roots that eventually run into the pots' sides, then turn and begin a circling pattern. But that's not the case with grow bags. When roots reach the sides of grow bags, they're exposed to air and come to a stop.
"They're literally 'air pruned,'" says Hogan. Plants are then forced to grow new roots, and in turn, develop healthier, more fibrous root systems and happier plants.
According to Hogan, the bags were first adopted in the greenhouse industry in the 1970-80s and gained value in rescuing plants after hurricanes damaged greenhouses. Today, the grow bags are becoming a popular way to grow food for home gardeners. They're available in gardening stores or online from sources like Ohio-based A.M. Leonard Inc.
The bags are made of fabric, most often felt, wool, burlap, recycled material or plastic. However, Hogan advises avoiding plastic options, since they aren't as breathable. Grow bags also come in a wide variety of colors and shades. In colder climates, try darker colors to gain a jump start on spring, since they warm up faster and hold heat longer. They're also available in decorative colors and with handles and ornamental accents like antique plant images. They vary in size from 1-gallon bags ideal for herbs to 200-gallon bags for a complete raised bed garden. Prices range $8 to $18 for a 5-gallon bag depending on their materials. Multi-packs offer the most cost savings.
To prep bags, Hogan says to fill bags with a quality potting mix and compost—not heavy soil from your garden. Add plants and top with two inches of mulch to help retain moisture. Water thoroughly, then place in a sunny spot. If you're worried about mess, place a saucer or pan underneath bags to catch soil that often drains with the water.
"You can grow almost any crop as in containers," says Hogan. Herbs are a good choice for beginners. Use smaller bags for the herbs as well as leaf lettuce, green onions and radishes. Tomato plants need at least a five-gallon bag per plant. Potato crops can be grown in larger bags. Even strawberry plants, blueberry bushes and dwarf fruit trees can be grown in bags.
The only drawbacks to grow bags are 1) they have a shorter life than pots – typically 4 to 5 years – and 2) they drain quickly so need watered more frequently. Hogan advises that if you're heading out of town for a long weekend, place grow bags in a kiddie pool with a few inches of water to keep them hydrated.
At the end of the growing season, just dump the soil from grow bags, fold the bags and store them for the winter. For more about growing food in grow bags and other containers, see the OSU blog post.