What Size Grow Bag For Tomatoes?

What Size Grow Bag For Tomatoes

Growing your tomatoes in grow bags is an excellent option to save space in your garden. But what size grow bag is best for tomatoes? 

Knowing the right bag size for growing tomatoes can be tricky for a first-time gardener. But do not worry – in this article, we will share everything you need to know about getting it right, so read on!

Benefits of using grow bags for tomatoes

Although grow bags have been used for planting since ancient times, gardeners have recently learned to love these alternative plant containers due to their numerous benefits. Here are some reasons grow bags might be a good option for growing tomatoes:

1. Grow bags offer portability

One of the many advantages of growing tomatoes in grow bags is portability. Unlike plants grown in garden beds, tomatoes in grow bags can be easily moved whenever necessary. Grow bags are also lightweight and designed with two handles, making them easy to pull along when moving your plants.

For example, you might need to move your tomato plants frequently to make sure that they are getting enough sunlight every day. This is the exact opposite of using traditional clay pots or containers, since those can be really heavy and inconvenient to move from one location to another.

2. Grow bags require minimal storage space

Unlike traditional clay pots or planters, grow bags do not take up a lot of storage space. Once the growing season is over, simply fold the bags and stash them away until you are ready to reuse them. This makes them the perfect option for gardeners with limited space.

3. Grow bags prevent drainage issues

Most tomato varieties require lots of watering to thrive. Unfortunately, this can also lead to waterlogged soil if you are using pots that have poor drainage.

Drainage issues are not a problem, however, if you are using fabric grow bags. Instead of keeping the soil soaking wet for extended periods, the extra water will simply drain out of the bag or evaporate through the fabric. Keeping the soil well-drained will help prevent root rot, pests, and harmful pathogens.

4. Grow bags prevent heat damage

Tomato plants grown in containers can easily suffer from excessive heat on hot summer days. With fabric grow bags, meanwhile, the heat will not be trapped inside since the material is breathable. The porous material of the bag will help keep the soil cool and prevent your plants from being roasted by the sun. 

5. Grow bags promote a stronger root system

Another perk of using grow bags for tomatoes is an improved root system, thanks to a process called air pruning.

If you plant your tomatoes in pots or plastic containers, their roots will continue to grow as they are not exposed to air. The pot’s limited space can turn all these roots into a dense, tangled mass. Eventually, the root-bound plant will stop growing and display signs similar to those of underwatering, such as wilting and browning of the leaves.

Unlike pots and plastic containers, grow bags have excellent aeration which exposes the roots to more air inside the bag. This process is known as air pruning, and it helps promote healthier and stronger plant roots.

What are determinate and indeterminate tomatoes?

Before we reveal the best grow bag size for tomatoes, it is important to know the variety of tomato plants you are planning to grow.

As you might know already, tomatoes come in different varieties, and each variety comes with different growth patterns and sizes. Fortunately, most grow bags are designed to be suitable for most types of tomatoes. Whether you are planting a determinate or indeterminate variety, there will be enough space for your plants to grow to their full potential.

Determinate tomato cultivars grow to a predetermined size – approximately three to four feet high. These varieties are also known for their bushy, compact appearance. Hence, smaller sizes of grow bags are usually sufficient for this type of tomato.

One thing to keep in mind is that determinate tomatoes produce fruit during the first growing cycle, typically within a period of two weeks. Once all the fruits have ripened, the plant will lose its vigor and will no longer produce new fruits. Because of this growth habit, determinate tomatoes are ideal for growers who want to grow and harvest their tomatoes in a short window of time. Afterwards, the plant can be discarded or you can take cuttings and start growing new tomato plants.

Some common determinate tomato varieties are:

  • Rutgers
  • Early girl
  • Celebrity
  • Roma

Indeterminate tomatoes, on the other hand, are varieties that can grow and produce fruits throughout the growing season, up until the plants are killed by hard frost. Although they are a bit slower to grow and produce fruit, you are guaranteed a continuous harvest. 

These plants also tend to be larger, with more vining branches than the determinate varieties. Hence, these varieties are best planted in larger grow bags. They can reach between 10 to 12 feet tall, so if you are growing indeterminate tomatoes, you need to have a large garden space to accommodate their huge size.   

Some of the popular indeterminate tomato varieties include:

  • Big mama
  • Beefsteak
  • Sungold
  • Brandywine
  • Better boy
  • Sweet million

What size grow bag is best for tomatoes?

The rule of thumb is to choose a large grow bag, depending on the tomato variety you are growing. The larger the bag, the better. Keep in mind that you also need to consider factors such as allowing sufficient space for the roots to grow.

So, you might be wondering – how many tomatoes can you grow in a 10-gallon bag?

Generally, growers use a 10-gallon grow bag for a single tomato plant. This bag size should provide space of 15 inches in diameter and a depth of 12 inches, which is sufficient for growing a healthy tomato plant.

But, if you are planning to grow more than one plant in a single bag, then the best grow bag size would be about 20 to 30 gallons. This size should provide a depth of 14 inches (or more) – enough to accommodate all the growing roots until they are fully established.

What about a smaller grow bag size? Are five-gallon grow bags good for tomatoes?

Yes, five-gallon grow bags are also fine for growing tomatoes, provided that the plants are the determinate and miniature varieties. You can even grow small-sized tomato plants in a two- or three-gallon bag. For best results, though, it is recommended to grow only a single tomato plant in a smaller-sized grow bag. Do not overcrowd your tomatoes in a single small bag or they will have to compete for moisture and nutrients.

What is the best grow bag for tomatoes?

Grow bags come not only in different sizes, but also different materials. We highly recommend choosing a bag that is breathable, well-draining, and reusable. It should also be convenient to fold and store until your next planting activity. 

Some of the best grow bags for tomatoes are:

  • VIVOSUN Plant Grow Bags: This grow bag is made of breathable fabric with strong handles attached, so you can move your tomato plants with ease. 
  • 247Garden Fabric Grow Bags: Like VIVOSUN, this grow bag is also made of fabric to provide good aeration for your plants, and also comes with sturdy bag handles. Aside from the standard sizes (three to 30 gallons), the bag is also available in 100 and 200 gallons.
  • Best Root Pouch from Maui Mike’s: If you are looking for an eco-friendly grow bag, then this is your best bet. These grow bags from Maui Mike’s are made from recycled water bottles and natural fibers designed to be breathable for the plants’ roots. They also come with sturdy handles for easy moving.  

Factors for choosing a grow bag for tomatoes

Grow bags are available in different sizes, shapes, and materials, so how do you know which one is best for your tomatoes? These important factors should help you make the right decision: 

1. Material type

Grow bags can be made of fabric, canvas, or felt. The material type depends entirely on your personal preferences, but the fabric ones are the most popular options among growers. We recommend sticking with fabric materials as they are more durable and breathable. 

2. Tomato variety

The type of tomato you intend to grow can greatly influence the size of your grow bag. If you are growing a determinate variety, then smaller bags are usually suitable since these tomatoes are compact and small. Indeterminate varieties, on the other hand, will generally require larger grow bags due to their bigger size and more established root systems.

3. Soil type

The type of soil you want to use for your tomatoes is also an important factor when choosing the size of your grow bag. A standard potting mix is the most recommended soil type for tomatoes. You can also use traditional garden soil, but this medium will require a larger grow bag to ensure that there are enough nutrients available for your plant.

4. Weather conditions

The weather conditions can greatly affect the watering needs of your plants. Keep in mind that grow bags are well-aerated, so they might dry very quickly on hot days. Smaller-sized grow bags will thus need to be watered more frequently than larger ones. If you are living in an area with high temperatures, then the larger grow bags might be best suited for your tomato plants. Rainy seasons, on the other hand, are a different story – make sure to adjust your watering to prevent oversaturated soil that can cause root rot.

5. Garden location

Whether you are growing your tomatoes indoors or outdoors will affect their care requirements, too. Hence, you will need to adjust the size of your grow bag according to the location of your tomato garden.


In summary, tomato plants need extra space to grow their roots healthily and produce the best yields. For this reason, choosing the correct size of grow bag is very important. A 10-gallon grow bag is usually the most recommended size for tomatoes, but you might need to adjust this depending on the variety of your tomatoes. Just remember that the larger the grow bag, the better it will be for your plants! 

Image: istockphoto.com / Vika-Viktoria