Grow bags are popular options when it comes to container gardening.
They’re lightweight and portable and aim to give your plant an ideal home to grow in.
In recent years, demand for grow bags has grown. And with it so has questions and concerns about their use.
In this article, I’ll answer some common questions about grow bags, so you can grow healthy, happy plants.
11 Grow Bag Questions Answered
As grow bags gain in popularity, gardeners have questions regarding safety, usage, and other key considerations. Let’s take a look at some of the most common concerns.
1. What Are Grow Bags Made From?
Grow bags are made from heavy-duty, nonwoven materials. They’re designed to withstand the wear and tear of holding soil and endure the sun, wind, and rain.
On top of durability, the nonwoven material allows for better airflow and for excess water to escape. This helps protect the roots from too much water.
Grow bags are usually constructed from polypropylene, a type of plastic. But rather than having a hard plastic shell, grow bags have a felt-like feel instead.
Plastic is not the only option with grow bags. You’ll also find ones made from natural fibers, such as hemp or cotton.
These bags are often biodegradable and eco-friendly. However, they’re not going to last as long as grow bags made from plastic.
Lastly, some grow bags combine natural materials with recycled plastics. These offer greater durability, yet are more environmentally friendly than bags made solely from polypropylene.
If being eco-conscious is important, then bags made from natural fibers, whether alone or combined with recycled plastic, are your best option.
Regardless of your material choice, remember that not all grow bags are the same. Some are no better than heavy-duty plastic bags. So take care when shopping, especially online.
2. Are Grow Bags Safe to Use for Vegetables?
With any grow bag, the material used will determine whether the bag is safe for your vegetables.
Most grow bags, even ones made from polypropylene, are considered food and garden safe.
But, though deemed safe, with plastic there’s always a chance chemicals can leach into the environment. This article from Epic Gardening is worth a read if using plastic is a concern for you,
With vegetables, your safest bet is to use bags made from natural fibers with little or no plastic in them.
Regardless of the material, make sure your grow bag is BPA-free.
And avoid grow bags that have been chemically treated to extend the life of the bag.
Remember, cheap options are often made with cheap, potentially questionable, materials.
3. How Long Do Grow Bags Last?
Generally, grow bags can last anywhere from 3 to 10 seasons, depending on several factors.
These include,
- The grow bag’s material. Natural, biodegradable fibers are great for the environment, but the bag won’t last long as one made from plastic.
- Exposure to the elements – sun, wind, rain. The more exposure, the shorter the life.
- How well you care for your grow bag at the season’s end. Storing your bag dirty or wet can lessen its life.
4. How Do Grow Bags Compare to Other Containers?
Grow bags have pros and cons compared to other containers.
Pros:
1. Grow bags are more breathable and provide better aeration and oxygen to roots, than containers made from harder materials. And that breathability can help prevent plants from becoming root bound.
When a root touches a regular pot’s side it starts circling the pot. This can eventually strangle your plant if left unattended.
On the other hand, if a root comes into contact with the side of a grow bag, it encounters drier soil and air. This prompts the root to stop growing and develop new roots instead.
Picture the end of a root protruding from the soil – rather than continuing to grow upward, the plant would produce new roots that dig deeper into the ground. This process is called air pruning.
2. Water passes more easily through grow bags, helping prevent over-watering and root rot.
3. Grow bags, especially lighter colored ones, help keep a more even soil temperature.
4. Natural fiber and recycled plastic options are more eco-friendly than plastic containers.
5. Grow bags usually come with handles, making them easier to maneuver.
6. Because grow bags are foldable, they’ll take up less storage space during the off season.
Cons:
1. Grow bags may not last as long as other containers. Especially biodegradable bags.
2. They can require more effort to get ready for winter storage.
3. Grow bags aren’t decorative like other containers are. They’re meant for growing plants. So, if you’re looking for something to spruce up your yard, a grow bag wouldn’t be an ideal choice.
5. Can You Grow Any Plant in a Grow Bag?
Generally speaking, if a plant can grow in a container, it can grow in a grow bag.
However, the best plants for grow bags are ones that don’t have deep roots.
Most vegetables will do well in a grow, as long as you’re not overcrowding your grow bag with either too many plants or too large a plant for the bag size.
Examples of good plants for grow bags include,
- potatoes
- cucumbers
- radishes
- beets
- carrots
- tomatoes
6. What Sizes Do Grow Bags Come In?
Grow bags come in various sizes and can range anywhere from 1 to 200 gallons.
For most vegetables, the 5 – 20 gallon range will do. I’ve written an article on grow bag size versus the number of plants it can hold. You’ll find it helpful when deciding which bag size will fit your needs.
And keep in mind, the larger the bag the more costly to fill and the more difficult to move.
7. What Should You Look For in a Grow Bag?
When choosing a grow bag, look for the following.
- The handles are sturdy and come with reinforced stitching.
- It’s made from nonwoven, breathable material.
- Is BPA-free.
- To go a step further, look for a bag that’s also AZO-free.
- For eco-friendly options, choose bags made from natural fibers or a combination of natural fibers and recycled fibers/plastics.
- A flat bottom for easy planting and standing.
- The correct sized bag for your planting needs.
Do your due diligence. A cheap bag made from cheap materials will not give you healthy vegetables or last as long.
8. Do You Need to Put Something Under a Grow Bag?
Whether or not you need something under your grow bag, depends on the bag’s location.
If your grow bag is on a solid surface, such as a patio or driveway, it can potentially leave a dirty ring. In this case, you may want to place a liner or saucer beneath the bag.
Alternatively, you can prop the grow bag up using bricks or even a plant caddy.
A grow bag sitting on a grassy area may kill the grass beneath the bag – at least for the current season.
The surface can also affect your watering schedule. Grow bags on hard surfaces get moisture only from watering or rain. Grow bags on soil or grass, however, can wick up moisture from the ground. So your plant may need less watering.
9. How Do You Prepare a Grow Bag for Planting?
Before planting, the first thing to do is to give your grow bag a thorough inspection. Look for problems such as
- wet or moldy spots
- fungus
- tears in the fabric
- frayed stitching on the handles
Once satisfied your grow bag has held up over the winter, let it sit open and empty for a day or two. This allows the bag to air out and regain its original shape if it’s been folded all winter.
Now, it’s time to fill the bag with soil, just as you would with any other garden container.
If you’re interested in learning more about container gardening, my beginner’s guide has a lot of helpful information.
10. Do Grow Bags Dry Out Faster Than Other Containers?
Because grow bags are made from nonwoven, breathable fabrics, they’re designed to have better aeration. This means the soil will dry out faster in a grow bag, especially as your plants mature.
Keep a close eye on the moisture level, checking your grow bag daily, especially during the heat of summer.
11. How Do You Store a Grow Bag for Winter?
To properly store your grow bag, you’ll first remove any soil. Once that’s done, wash your bag with soapy water. Rinse well, then allow the bag to fully air dry before folding and storing it away.
Don’t skip the air drying. Packing your grow bag away wet can encourage fungus and mold.
Though grow bags need extra care for winter storage it’s worth the effort. Proper care will help extend the life of your grow bag.
If your climate permits, you can continue to use your grow bag through the winter, harvesting vegetables like carrots, potatoes, or other root crops. However, keep in mind that continued use may cause the bag to degrade faster. And this is not feasible in colder northern climates with harsh winters and heavy frosts.
Final Thoughts
- Grow bags resemble felt, but are made from plastic, natural fibers, or a combination of both.
- Grow bags come in various sizes.
- The size of your grow bag should be large enough to accommodate the size of your plant(s).
- Grow bags can last up to 3 – 10 seasons, depending on how well they are cared for and the type of material they’re made from.
- Plants in grow bags may need watering more often.
- Grow bags should be emptied and stored away dry at the end of the season.
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