Why you should use a grow bag (& how to make grow bags)

I highly recommend pot and container gardeners to use grow bags. Actually, any gardener should look into grow bags as it is, in many ways, superior to the traditional plastic or composite pots.

In this article I will discuss 4 advantages of grow bags. I will also show you how to make your own grow bags for considerably less than buying pots, containers (or grow bags). You will find a written step-by-step guide with photos as well as a “How to make grow bags” video tutorial below.

For me, I have to admit, starting to use grow bags for our plants was initially all about cost. And I was at the time unaware of the other benefits grow bags deliver.

If you came here for instructions on how to make grow bags at home, feel free to skip ahead to the DIY grow bag tutorial with photos. Or if you prefer, watch the instructional YouTube video Beginners guide to making DIY grow bags at home below. But if you have a few minutes to spare, I recommend you read on. You will learn a lot about the advantages of using grow bags when reading about my journey to using grow bags for my plants and vegetables.

Plastic and composite pots get expensive with size

I grow many larger types of vegetables in our garden. And it was really hard to find inexpensive larger size pots.

I needed larger pots for beefsteak tomato plants and chillies. The plants grow large and they need space and moisture to develop and thrive.

But when a pot hits a certain size it seems to be the norm that the manufacturers focus on design over functionality. The pots will look really great but often come without drainage holes. And even if I want my garden to look nice, function is often more important than design.

I do not want to pay for an outdoor cachepot or planter. I want a functional pot to grow my plants and vegetables.

And where I live there seems to be an unspoken rule that all pots larger than 30 centimeters (12 inches or about 1 square foot) need to look great.

Starting to use grow bags

Last year we bought a Japanese maple (Acer palmatum) for our garden. The tree was delivered in a grow bag. 

This simple incident made me go back and revisit grow bags and I bought a couple at an online retailer.

It worked great and I could get the size I wanted for a reasonable cost.

I ended up growing tomatoes and chilis in my new grow bags. Not long after my wife confidently stated that she could make homemade grow bags using her Singer sewing machine that would be at least as good as the ones I had purchased.

To make a long story short, I now know how to make my own grow bags. Yes, even I can do it. DIY grow bags are not that difficult to make as it turns out.

It is pure mechanics and the hardest part is setting up the machine and threading that *beep* needle. And that is more fiddly than difficult to be honest.

Cost + 3 additional advantages of grow bags

Cost is of course a major advantage of grow bags – especially when you make your own.

But besides cost, grow bags offer 3 additional advantages over plastic or composite pots.

  • grow bags promote healthier root systems
  • as a grow bag is made from breathable fabric it helps control water levels
  • grow bags are versatile (use them for any plant) and light (easy to move around)

1. Grow bags promote healthier root systems

When you move plants from plastic pots you will sometimes find a root system that seems to grow in circles. The root system follows the side of the plastic pot perfectly.

When you grow plants in plastic pots that do not breathe the roots will continue to grow when they hit the side of the pot.

And as they cannot go back or though the side the roots simply follow the sides of your plastic pots. You have probably heard the expression pot or root bound.

After all, as a plastic pot does not breathe, the soil will be moist and the roots will consequently continue to grow in their search for water and nutrition.

And there is nothing else to do than to follow the container and around we go. This will stifle the growth of the plant. The plants will use a lot of energy to grow long roots in search for better soil that simply is not there.

When you use DIY grow bags this will never happen.

The magic of breathable fabric grow bags

As grow bags are made from breathable fabric the roots will reach a drier soil towards the edge of the grow bag. The roots will get the message and stop growing in that direction and instead focus energy on growing new feeder roots inside the grow bag.

This results is a heather and more efficient root system that will help your plants grow and thrive.

The phenomenon is referred to as air pruning. The roots stop growing when they reach the soil in contact with air through the grow bag fabric.

Do not use any material you have at home to make your DIY grow bags. The fabric must breath.

2. Fabric that breathes helps control water levels

Grow bags are made from breathable material. And as the fabric is breathable, excess water can evaporate. This also eliminates the need for drainage holes.

It is so easy to over water plants. Overwatering is often the result of a well meaning gardener who wants a healthier plant and instantly reacts to dry surface soil.

But the surface does not tell you anything conclusive about the level of moisture in your pot, container or grow bag.

When you use grow bags the whole container is made from a fabric that breathes. 

Grow bags help reduce the risk of root rot due to a plant sitting in a pot full of water due to overwatering or blocked drain holes.

3. Grow bags are versatile and light

Grow bags are extremely light. With homemade grow bags you are basically carrying the soil and the plant itself.

This is useful when you need to protect our plants from wind, rail or even sun during extreme periods of the year.

And you can arrange your bags any way you like. Arrange 12 grow bags in rows of fours and you have created the illusion of a raised garden bed. Looks great and can just as easily be re-arranged.

Are you growing plants or flowers that need to spend time inside during the cooler months of the year? Simply carry your grow bags into a more sheltered location.

If you are short of space, cover them with fabric, wrap the grow bag in bubble wrap and raise them from the ground and let them overwinter outside.

And when you are done with your grow bags for the season you simply rinse them off, fold them and store them for future use. 

Couldn’t be easier.

Beginners guide to making DIY grow bags at home

Watch this video on YouTube.

When you grow a lot of larger types of plants and vegetables, cost does become an issue.

You always need good soil mixes and seeds or seedlings.

But larger size pots do get expensive. And even if you only want them to serve a function, you often end up paying for design when it comes to larger sized outdoors cachepots or planters.

You can save money when you use grow bags. Especially when you make your own grow bags at home.

Materials needed for making your own grow bags:

  • Sewing machine (optional if you prefer to sew grow bags by hand)
  • Pair of scissors
  • Chalk or pen to mark
  • Pins
  • Rules or measuring tape
  • Landscape fabric (breathable material)
  • Thread (outdoor durable thread)

If you own a machine you should have all the material at home with the exception of the landscape fabric.

Landscape fabric and outdoor thread can be bought online or at most Home Improvement Stores. 

I usually buy a roll of black landscape fabric measuring 10 meters x 1 meter (roughly 3ft x 21ft). This black landscape fabric is the same fabric I use for weed and plant control when for example growing horseradish.

I have found that 10 x 1 meters (roughly 3ft x 21ft) will make 10 medium sized (1 square foot) grow bags. The medium sized grow bags we make hold 27 litres (7 US gallons / 6 Imperial gallons)

Whatever size you buy, make sure you use all the fabric. Even if you make different size grow bags.

In this guide I am using a white thread as it makes everything clearer. I do recommend using black thread for your brow bags as it is “invisible” and a lot more forgiving.

Also, you can click all images below for a larger sized image to open in a separate tab or window on your mobile or computer.

Making grow bags at home – step by step with photos

1. Cut fabric to size

Use 4 layers of fabric
Cut 4 squares measuring 50 x 50 centimeters (roughly 20 x 20 inches). 

These measurements will give you a medium size bag with a diameter and depth of 30 centimeters (12 inches). Or about a 1 square foot grow bag if you prefer.

Volume: 27 litres (7 US gallons / 6 Imperial gallons)

Remember to move the cat before moving on.

2. Place the sheets of fabric on top of eachother

Grab the materials by the corners and stretch to make them fit on top of each other.

3. Pin 2 sides together

Pin layers together
Pin two opposite sides together. 3 pins per side works fine to secure the fabric. 

Seam allowance, place the pins roughly 2.5 centimeters (1 inch) from the edge of the fabric.

4. Sew the pinned sides 

Now sew the pinned sides together along the top edge. 

Use a straight stitch. To reinforce the seam, sew a zigzag seam on top of the straight seam for larger type bags.
When sides are sewn together your bag will look like this. 

As you see you do not have to worry about perfectly straight stitching. 

Try your best and you will be fine.

5. Grab center of fabric to center the stitched seams

Center the seams by gently pulling the fabric
Separate the sheets and gently pull the fabric to position the stitched seams in the center of the fabric.

Place the fabric back on the table and make sure that the stitched seams are in the middle of the fabric and that the stitched seams overlap.

6. Pin one of the open sides

Pin one of the open sides together using 3-5 pins.

7. Sew the pinned side

Sew the pinned side using a straight stitch. Reinforce with a zigzag seam for lager type bags.

8. Place the sheets back to original position

Separate the sheets (open side) and hold two sheets in each hand.

Now turn the sheets to place the original seams back to their original position.
You will now have two triangle type shapes forming.

Press the fabric with your hands to make sure that all looks symmetrical.

9. Fold tip of triangle to centerline

Fold tip of triangle to center line to mark the middle line
Grab the tip of one of the triangle shapes and fold it back to the center. The tip of the triangle should touch the center line of the grow bag.

Press down to create a fold in the fabric.

Use your pen or marker to draw a line in the fold and pin across your marking.

Repeat the process for the second triangle shape.

10. Sew along the marked lines of the grow bag

Pins marking center of triangle
Use a straight stitch to sew along the marked and pinned line. 

Make sure to remove the pins to avoid breaking your needle.

Do this for both lines and triangle shapes.

As you can see it does not need to be perfectly straight to work.

11. Pin and stitch around the open side

You can now see your bag taking form. We now need to sew the edge of the top of the grow bag.

Pin the sides together. Place the pins about 3 centimeters (1 inch) from the edge of the fabric. You can place the pins 6 centimeters (2 inches) apart.

Now sew around the edge with a straight seam.

12. Fold the edge over and pin in place

Fold and sew to create a nice finish
Final step. We will now create a nice smooth finish to the edge of our grow bag.

Fold the edge over itself and pin in place. Fold as much or as little fabric as you want but it is easier if you use more fabric.

Secure the pins all around and then sew along the top of the fabric to join the pieces together.

Cats also love grow bags

And you are done!

All you need to do now is to turn the grow bag “inside out” to get all the seams on the inside of the bag.

As you turn the grow bag “inside out” you gently push the corners out to create an “inner square” at the bottom of your grow bag.

Push the triangles you created down to cover the bottom of your grow bag. Use your fingers to get all the way in to the corners.

Final words, making grow bags is not difficult. Try it. When the first one is done you will be making grow bags with ease and you will thank me for it.

Frequently asked questions

Meet the author: Mattias is an experienced gardener spending most of his free time on his knees among herbs, plants and garden vegetables. For the past two years he has been sharing gardening projects and how-to tutorials on the NordicLavender website and YouTube channel.