Growing Tomatoes in Grow Bags: A Comprehensive Guide

3 tomato plants in a row along a building. Planted in black grow bags.
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Growing tomatoes in grow bags is rapidly becoming a popular way to garden in small spaces while reducing disease pressure. 

As someone who has never been able to grow a tomato due to heavy blight in my area, using grow bags has made growing tomatoes possible for me!

In this article, we’ll discuss which grow bags to use, how to grow tomatoes in grow bags, which tomato varieties are best, plus tips for an excellent tomato harvest!

Let’s jump in!

Why Use Grow Bags?

The use of grow bags has really skyrocketed the past few years, and there’s many reasons why they are a great option for growing!

  • Short on Space – Using grow bags makes tomato growing possible in tight spaces like a deck, patio, porch, driveway, you name it!
  • Disease Pressure – Elevating the tomato plant, growing it in a sterilized potting mix, and placing it away from other plants (deck, patio, etc.) greatly reduces the risk of disease
  • Good Airflow and Drainage for Healthy Roots – Grow bags utilize “air pruning” for a healthy root system (read more about this below!)
  • Portable – Grow bags can be moved around throughout the growing season. You can even move them indoors in the fall to extend your harvest!
  • Inexpensive – Buying a few grow bags is much cheaper than building a raised bed or buying planter pots!

Types of Grow Bags

There are a few different types of grow bags on the market, plus some DIY options. Let’s break them down!

Fabric Grow Bag

This is the best option, in my opinion. Fabric is breathable, resulting in healthy plants with a strong root system. Fabric is also sturdy and many of these models come with handles, so you can move your grow bags indoors if a storm is coming, or winter!

This is the most popular grow bag on the market!

These sturdy grow bags are made of thickened nonwoven, BPA-free frabric that allows for good drainage. Features durable, reinforced handles for easy moving. Comes in 15, 20 or 25 gallons - perfect for tomatoes! 

*20 gallon size = 19.9" Diameter 15.9" H

At $25, this is a screaming deal!

Made of high quality, durable, BPA-free non-woven fabric. These grow bags are even washable for reuse! These grow bags provide excellent aeration and good air permeability. The handles are double thick and double stitched to the bag for easy moving. Comes in 15, 20 or 25 galls as well. 

*20 gallon size = 20.5" Diameter, 14.5" H

This is the deepest grow bag that I've found, and tomatoes love to be planted deep!

These grow bags are made from BPA-free polyproplylene with sturdy nylon handles. Allows for excellent drainage. Can be hand/machine-washed and reused for many seasons. 

*20 gallon size = 16.8" Diameter, 18" H

Plastic Grow Bag

There are a few plastic grow bags on the market, however, plastic is my least favorite option. Not only is plastic… well, plastic, but it also doesn’t breathe very well and has a tendency to get brittle in the sun. No one wants root rot or their grow bag splitting open halfway through the season.

The models that I’ve seen also appear very top-heavy and I fear that they’ll topple over when paired with a vertical plant like the tomato. Per the reviews, they don’t seem to last longer than a season or two. Skip the plastic grow bags.

5 Gallon Bucket

You may see others utilizing this method, however, I don’t recommend it. 5 gallons is too small for a large plant with an extensive root system like the tomato. If you want to go for it, make sure to drill drainage holes and know that your plant’s growth may be stunted.

DIY Tomato Grow Bags

Woven Basket Lined With Landscaping Fabric

I’ve used this method before when I was trying to make use of materials that I had on hand. It’ll work in a pinch as long as your basket is fairly large, however, don’t expect a bountiful harvest. I also found that it drained too well and was prone to drying out.

Empty Feed or Birdseed Bags

I love finding ways to repurpose stuff that would otherwise be thrown away! This is a neat method to try, however, I do worry about the shape of feed bags. They are going to be prone to toppling over due to their skinny and tall shape, plus adding the tall nature of tomato plants.

White bags filled with grain in a row

If you want to give it a try, you can read more about it in this article How to Make a Feedbag Garden by HobbyFarms.

Directly Into A Compost Bag With a Growing Ring

Some people have experimented with growing their tomato plants directly out of a compost bag! This method uses the bag in a horizontal position, so it will be more stable. You can read more about the processes in this article by Gardeners’ World. 

While it is a tempting option, I worry that it doesn’t provide sufficient depth. Tomatoes have deep root systems and thrive when they are planted deep into the soil..

Steps for Growing Tomatoes in Grow Bags

Supplies List

How-To:

1) Place your empty grow bag in a location with 8 hours of direct sunlight a day.

2) Fill grow bag halfway with organic potting mix

A grow bag halfway filled with potting soil

3) Snip off your tomato plant’s bottom set of leaves (see photo with arrows pointing to which ones should be removed) with clean scissors or garden shears. Trust me!

Arrows pointing to the bottom set of leaves on a tomato plant

4) Place tomato plant in your grow bag and fill the the rest of the way, up to 2” below the bottom set of remaining leaves. By burying the bottom section of the tomato stem, it will begin to grow roots for a stronger root system. Tomatoes like to be buried deep!

freshly planted tomato plant in a planting bag

5) Add a 1″ layer of compost (tomatoes are heavy feeders)

6) Secure your tomato plant with a tomato cage, so it doesn’t topple over. Be careful not to pierce the fabric.

7) Mulch with organic wood chips (NOT the treated stuff in bags for landscaping) or organic straw to retain moisture and the reduce the risk of disease

A completed planting of a tomato in a grow bag outside

8) Water thoroughly

Tips for Growing Tomatoes in Grow Bags

Choose the Right Variety

There are two main classes of tomatoes: determinate and indeterminate

Many types of tomatoes spread out over a wooden table

Determinate – preferred

Determinate tomatoes grow more like a bush, rather than sprawling vines. That means that these varieties will have a more compact nature and less likely to become a big mess and topple over.

Indeterminate – not ideal

Indeterminate tomatoes are high-producing, however, they can easily take over the space that they are planted in. They need consistent pruning, training and trellising to keep them contained. Indeterminate tomatoes are best used in the garden rather than grow bags.

Provide Adequate Sunlight

Tomatoes need adequate direct sunlight for strong growth and prolific fruit production. Find the sunniest location near your home and place your grow bags here. Ideally, this location should have 8 hours of direct sunlight per day.

Fertilize Frequently

Tomatoes are very heavy feeders, especially once they start to develop fruit. Make sure to fertilize every 2-3 weeks with an organic fertilizer. I prefer organic fish emulsion. It’s stinky, but it works really well! 

Organic, highly nutritional protein fertilizer made with naturally occurring enzymes present in fresh north atlantic fish. Slowly breaks down into basic compounds when added to soil and promotes the growth of beneficial bacteria.

Water Regularly

Potting soil is light and drains well, which means we will need to water frequently. If there’s no rain in the forecast, water daily. If it’s exceptionally hot out, water twice daily to keep the roots cool. 

Adding organic mulch (see options in next section!) to the top few inches of your grow bags will help retain moisture. If you are busy or travel a lot, a drip irrigation system can be a life-saver!

Reduce Disease Pressure

Tomatoes are very susceptible to soil-borne disease such as early blight. To prevent this, prune off any branches that are touching the soil with clean scissors or garden shears. Watering the soil directly instead of the foliage is a great step to keeping disease at bay.

Lastly, adding mulch to the top layer of soil can help keep soil organisms from splashing up on the leaves. If you can source organic straw from a local farm, that’s my favorite option! Or if you chop your own firewood like us, you’ll have plenty of natural wood chips to choose from. If you don’t have access to these options, check out the products below.

This organic hardwod bark mulch is a great, natural option to retain moisture and reduce disease when using growing bags. Add a 2" layer to the top of each growing bag.

Premium Organic 100% All Natural Wheat Straw that's perfect for mulching growing bags, or anywhere in the garden! Add a 2" layer to the top of each growing bag.

Prune Suckers Weekly

Tomatoes are vigorous growers, and not all of its growth is good. Tomatoes are prone to growing “suckers,” or new stems that will not flower or produce fruit. If left in place, they will “suck” resources from the plant while crowding out the producing stems. 

Suckers grow between the main stem and the leaf crotches, so be on the lookout for these! If caught early, they can be easily pulled off with your fingers. You can learn more about pruning tomato suckers in this article by Gardening Know How.

FAQ About Growing Tomatoes in Grow Bags

What size of grow bag should I use?

This is the most important part! Tomato plants may seem small when you first get your seedlings, but they will get HUGE. Tomatoes are one of the largest vegetable plants out there and they have extensive, deep root systems. 

So what size should you use? Choose a grow bag that holds 15-25 gallons. The bigger, the better! The biggest mistake that I see gardeners make is choosing a grow bag that is too small. This will result in stunted growth and an increased risk of toppling over.

What type of soil should I use for grow bags?

Picking the right soil mix is essential to the health of your tomato plants. When grown in a container, you want to ensure that you are using a potting mix because it drains well. You don’t want soggy roots! Avoid using plain garden soil as this doesn’t drain well enough.

Fox Farm Garden Soil is Lightweight and well-aerated, it is specially formulated to grow seedlings in a container. This product is soil pH-adjusted at 6.3 to 6.8 to allow for optimum fertilizer uptake.

If you are using multiple grow bags like me, it will be more cost-effective to find it “by the scoop” at your local garden center. My garden center sells a great potting mix for $80 per yard. Make sure you aren’t buying plain old top soil!

How do you support tomatoes in grow bags?

My favorite way to support tomatoes is using the traditional tomato cages. These are easy to set up (be careful not to puncture your grow bag) and work really well as long as you get the right kind. 

Tomato cages vary quite a bit. Some have very small gauged wire and are small in size; don’t be tempted to buy these cheap ones! You will be sorry. Purchase the biggest ones you can find at your garden center with a nice thick gauge.

Do tomatoes do well in grow bags?

Yes, as long as they are watered regularly and given adequate space and sunshine. They may not produce quite as much as a tomato plant grown directly in a garden, but they still do quite well!

If you’re like me and live in an area that tends to have a heavy infestation of early blight, your tomatoes may do better in grow bags than in the garden!

When should you put tomato plants in grow bags?

It’s time to plant tomatoes when the soil temperature is above 55-60 degrees and the air temperature doesn’t drop below 45 degrees at night. 

tomato seedlings in pots on the ground waiting to be planted

Is it best to grow tomatoes in pots or grow bags?

Grow bags are far superior to pots when growing tomatoes. Pots are heavy, breakable, expensive, and often have poor drainage as well. Pots can also “bake” in the heat, frying your poor tomato plants.

Lastly, grow bags utilize “air pruning” for a healthy root system. When the roots reach the drier soil on the bag’s exterior, the roots stop growing and branch out. Creating an extensive web of healthy roots. In pots, the roots continue to grow and wrap around the pot’s exterior, eventually strangling the tomato plant.

How deep does a grow bag need to be for tomatoes?

Grow bags should be a minimum of 12” deep for growing tomatoes. The deeper, the better!

Are grow bags toxic?

It depends on the material of your grow bag, but most of them are not. The recommendations that I’ve provided above are all made of a non-woven, felt-like material that is BPA-free. This material is considered safe for storing food, so it should be safe for growing food, too!

Other Articles You’ll Love

The 6 Best Vertical Garden Kits in 2022

5 Winter Tasks Every Gardener Should Do

Rhubarb Companion Plants: Friend or Foe?

Final Thoughts

Growing tomatoes in grow bags is a simple, inexpensive way to grow delicious food in small spaces. You can grow more than tomatoes in grow bags, too! Get creative and try different combinations.

Remember, the bigger, the better when picking grow bag sizes for tomatoes. Don’t skimp there! 

Happy gardening!

Thanks for reading signature

*All of the information above was referenced from my favorite gardening book The Vegetable Gardener’s Bible and personal experience, unless otherwise specified.

Achieve Your Best Harvest Yet!​

I’ve been using my Garden Growing Guide for years and I know that you’ll love it, too. It’s fully customizable to your growing zone and can be printed or used digitally. Happy Gardening!

14 thoughts on “Growing Tomatoes in Grow Bags: A Comprehensive Guide”

  1. Great article! I’ve never heard of growing tomatoes in bags before but you had a ton of helpful information for learning how to do this method. Thanks for sharing!

  2. GREAT information!! Though, we’re actually trying tomatoes in 5-gallon buckets this year. To top it off, they’re indeterminates. LOL Hopefully they’ll do ok. Next year, we’ll have this article to guide us to do it the right way! 😉

  3. What perfect timing! I started gardening this year and was wanting to do my tomatoes in containers instead of raised beds. This is just the info I was looking for!

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