This newly planted geranium will thrive in its grow bag.

One gardening practice that does not require digging in the ground is the use of grow bags for raising flowers and vegetables. Grow bags are not clay or plastic pots; rather, they are fabric bags which hold soil for growing plants outdoors and in greenhouses.

These bags are a very functional and viable alternative for gardeners who have limited space for growing plants or who want to experiment with new plants or locations. Using grow bags is like having a temporary raised garden; but when the growing season is completed, you can empty the bag, fold it up, and store it for next year.

Grow bags are porous and allow air into the soil, producing healthier root systems. When roots encounter air, they stop growing in that direction, becoming “air pruned.” As a result, the plant forms more roots, resulting in vigorous plant growth.

Garlic, planted last fall, emerges from the grow bag.

In comparison, the roots of plants grown in plastic containers reach the plastic walls and continue to grow in a circle around the root ball. The plant will then become root bound and be less able to absorb water and nutrients, which may result in inefficient plant growth and less crop productivity.

Grow bags are available in a variety of sizes and fabrics; some have drainage holes at the base to prevent over watering. The material in grow bags is a spun-bond fabric, often polyethylene (recycled plastic bottles) or polypropylene. Purchase bags that have handles attached (sewn) to a sizable area of the bag; handles that are tacked on the outside can fail over time. While grow bags are light when empty, once filled with potting soil and mature plants, secure handles are a necessity for safely moving or repositioning bags during the growing season.

When gardening with grow bags, decide in advance the crop to be grown and the location to site the bags. Plants and seed packets that are labeled for containers will do especially well in grow bags. Match the choice of bag to the intended crop. A minimum of five gallons per plant is recommended. Use wide and shallow grow bags for lettuce, onions, spinach, radishes, herbs and shorter flowers. Deep grow bags are needed for tomatoes, peppers, carrots and deep-rooted plants. Indeterminate tomatoes will appreciate 10 gallon bags, while determinate tomatoes will be content in five gallon bags. Cucumbers and tomatoes will need support from cages or stakes.

Site the grow bags in the appropriate sun conditions for the planted crop. Grow bags work best when placed on soil to prevent stains on decks and patios and keep the bags from drying out too quickly. Once placed in the proper location, line the bottom of the bag with perlite or pebbles to help water draining and prevent root rot. Add the soil mixture, which could be a compost-based, container-based, or other soil mixture that permits drainage.

Shake the grow bag and allow the soil to settle into the shape of the bag; fill the bag to about one inch from the top. Gently place the seeds or plants into the soil and water thoroughly. Because grow bags offer better soil aeration and drainage compared to plastic containers, over-watering plants can be prevented. However, during periods of hot temperatures and low humidity, frequent watering will be needed.

Grow bags have endless possibilities for gardening.

Would you like to grow more plants but space is at a premium? Tuck grow bags of interesting annuals and flowering plants into your landscape to attract pollinators and add color and texture.

Do you want to experiment with something you have not grown in the past? Try a grow bag before committing a garden space or to more of these plants.

Are you finding a lack of garden space to rotate crops? Try giving that garden space a rest and planting those crops in grow bags. For example, tomatoes and peppers are members of the nightshade family. Growing them year after year in the same soil will cause soil pathogens to build up, resulting in disappointing yields and possible crop failure. Plant tomatoes and peppers in separate grow bags and give your garden beds an opportunity recover.

Does your soil composition have too much clay or rocks for root crops? Grow bags are ideal for growing and harvesting root crops. Potatoes or sweet potatoes planted in grow bags will not require a fork to dig them out of the soil. Purchase grow bags with side flaps where you can reach in and remove tubers without damaging the crop.

Purchase grow bags at a local nursery, garden store or online vendor. Try different types of bags to learn which materials work best for your needs. Explore the flexibility and possibilities offered by grow bags!

If you have questions about gardening practices or using grow bags, call the Butler County Master Gardener Garden Hotline at 724-287 4761, ext. 7, or email the Master Gardeners at butlermg@psu.edu.

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Monica Huselton is a Penn State Extension Butler County Master Gardener.