What Size Grow Bag for Tomatoes Should You Use?

Limited garden space or not having a garden or lawn should not stop you from growing tomatoes at home. You only need adequate space indoors or outdoors to accommodate a couple of grow bags, and you’re good to go.

Even so, you’ll need to decide what size of grow bag is perfect for your tomatoes. So you may be asking, what is the best size grow bag for tomatoes to use?

Basically, you will need 10 gallon grow bags for determinate tomatoes, 20 gallon bags for indeterminate tomato plants, and 5-7 gallon bags for smaller tomato varieties such as cherry tomatoes. The smallest grow bag for tomatoes should be at least 15 inches (38cm) in diameter and at least 12 inches (30 cm) deep.

Follow along as we discuss how to choose grow bag sizes for tomatoes as well as the best size grow bag for growing your tomatoes.

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Are Grow Bags Good for Tomatoes?

Yes, grow bags are suitable for growing tomatoes for the following reasons:

Grow bags have breathable fabric that allows adequate soil aeration and dissipation of excessive heat.
They are lightweight and highly portable. The two handles allow for easy movement of your plants to cater to their different needs like sunlight exposure.
Grow bags are reusable and easy to store post-growing season.
The frequent need for watering growing tomato plants can result in drainage problems for pots and other containers, but not with grow bags. The excess water evaporates quickly as it seeps into the grow bag’s fabric.
Growing tomatoes in grow bags encourages the development of a robust root system in plants and prevents root-bounding thanks to their excellent aeration.

Factors Determining What Size Grow Bag is Best for Tomatoes

Grow bags range from 5-gallon sizes to even 1000-gallon. And while you can grow tomatoes in small grow bags, you shouldn’t.

Your plants will be space-constrained, which affects root development, thus insufficient water and nutrients intake. Technically, small grow bags will result in stunted plants with poor yields and subpar produce taste.

But how do you decide if a grow bag is small for your tomato crop?

Consider the following factors while choosing the right to grow bag size:

Tomato Variety: Smaller tomato varieties need small grow bags and vice versa.
Soil Quality: Ideally, you should use potting soil while planting tomatoes in grow bags. But if you decide to use your garden soil, then a bigger grow bag will carry more soil to ensure your plants get as many nutrients as possible.
Indoor or Outdoor Plantation: Outdoor and indoor tomato growing present different plant care and watering needs, and the size of the bag should vary too.
Portability and Location: The location and need for movement of your crops frequently are important size determining factors. Also, consider conditions for different seasons like excessive heat in summer to avoid baking the plant roots in small grow bags or root rot in rainy season.

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Determinate vs. Indeterminate Tomatoes

Determinate and indeterminate tomatoes have different growth patterns, sizes, and fruiting patterns. Hence, each does well in grow bags with enough space to accommodate their characteristics.

For a start, determinate tomatoes have a compact size with a bushy appearance. They are perfect for gardeners who wish to harvest and process all their tomato produce at the same time, as they yield their entire crop at once.

You can try popular determinate tomato varieties like Celebrity, Early Girl, Roma, or Rutgers, among others. Check the seeds’ catalog for the “DET” abbreviation to ensure the seeds are for determinate tomatoes.

On the other hand, indeterminate tomatoes (abbreviated on catalogs as “INDET”) can grow over 5 feet in height. Their stakes and vines are longer and require support for the stems. If you love fresh, tasty tomatoes throughout the season, then indeterminate tomatoes are the best for you, as they yield all season long.

Popular indeterminate tomato varieties include Better Boy, Big Mama, Beefsteak, among others.

What Size Grow Bag for Indeterminate Tomatoes?

Full-grown tomato plants need a robust root system for support and nutrients, and water uptake. And for indeterminate varieties and their huge sizes, the more developed the root system, the better.

Many crop experts recommend you use a 20-gallon or larger grow bag for indeterminate tomato varieties. Simply put, a grow bag with at least 15 inches in diameter and at least 12 inches in depth.

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What Size Grow Bag for Determinate Tomatoes?

As stated earlier, determinate tomato varieties are smaller and hence can do well in smaller grow bags.

Most determinate varieties will do well in 10 gallons, or larger grow bags. On average, grow bags with a diameter of at least 10 inches and heights above 8 inches. But the general rule here is, the bigger the grow bag, the better, irrespective of the tomato variety.

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Tips for Growing Tomatoes in Grow Bags

Here are some tips for growing tomatoes in grow bags:

Tomatoes need at least 8 hours of sunlight. Thus, keep your crops in a sunny, bright, and well-ventilated location.
Plant your tomatoes deep to encourage as many roots as possible to develop.
Frequently water your plants as grow bags encourage quick water loss through evaporation.
Ensure the soil you use has high nutrient levels. You can add crushed eggshells to boost calcium levels and fertilizers as needed.
Consider planting different tomato varieties with varying yielding times to have a steady yield all season long.

Can I Grow Tomatoes in 5 Gallon Grow Bags?

Tomatoes are heavy feeders and need as much space as possible to grow healthy, flower and fruit. So the bigger the grow bag the better. You can grow the smaller varieties such as cherry tomatoes in 5 gallon bags. However, if you want to get bountiful harvest from your effort, I would suggest you use bigger grow bags.

What is the Best Size Grow Bag for Tomatoes? Final Thoughts

Limited garden space should not keep you from enjoying homegrown tomatoes, thanks to grow bags. But, growing your tomatoes in the correct size grow bags will ensure your plants are healthy and yield heavily.

If possible, grow your plants in the biggest grow bag your location can accommodate. And, when constrained, ensure you plant indeterminate varieties in 20+ gallons grow bags and use 10+ gallons grow bags for determinate varieties. All in all, good space almost guarantees healthy plant growth.