Garden Variety: The benefits of gardening using fabric containers

Fabric planting containers may seem like just the latest trend in the garden center, but they truly offer gardeners a better option for container gardening than the traditional plastic, clay and other pots out there.

The fabric bags are made of a thick, felt-like material, styled similarly to plastic grow bags that have been around for decades. They are sold under a variety of brand names including Gro Pot, GeoPot and Smart Pot.

Fabric planting containers allow plants to maximize their root growth. In a hard-surfaced container, plant roots grow outward until they reach the inside surface of the container. From that point, they are forced to grow down or sideways, or both. If they grow down, they will reach another border, and typically roots end up looping around and around the pot depending on the vigor of the plant. In containers with porous surfaces such as unglazed terra cotta and wood, plant roots may attempt to penetrate the material but still usually end up circling the inside perimeter.

In a fabric container, plant roots can penetrate into the fabric. When the growing point or tip of the root is far enough into the fabric to completely dry out, it will die back a tiny bit and encourage more roots to form along the main portion of the root. The process is called air pruning or air root pruning and is popular in tree production. Containers that allow for air pruning produce healthier, better-branched root systems than traditional containers. Heavily-branched root systems are more efficient at taking up water and nutrients, thus yielding healthier plants.

Fabric planting containers are reusable from year to year just like hard-surfaced pots and may even withstand winter weather better if left outside.

There are a few disadvantages of using fabric planting containers. First, they are difficult to move once they are filled with soil. The best bet is to set the pot where it will remain for the season prior to filling it with potting mix (soil). To store it for the winter, shovel the soil out until the bag can be lifted and dumped. Old potting mix can be mixed into garden areas or added to the compost bin.

Another disadvantage of fabric planting containers is the aesthetic quality. Even for gardeners who are more interested in their tomatoes than the look of the containers, the black and tan pots are boring at best. A simple fix is to add a few draping annual flowers to whatever else is growing in the pots. One petunia plant or a few sweet alyssum will brighten any garden. A sweet potato vine will also cover the pot, but are best used only if you want to fill the pot with sweet potatoes.