Gardening Growing Tomatoes

What Size Pot for Tomatoes & How Much Potting Soil Do I Need

Growing tomatoes in containers are very popular for gardeners who have space limitations. Besides some hobby gardeners also try potting tomatoes for new experiments and other purposes. Nonetheless choosing the right size of pots for your different tomato varieties is a little bit confusing for the beginners.

People often ask “What size pot for tomatoes?”.

That’s why I tell today which container size best suits for your particular tomato variety and how much potting soil do you actually need for that pot.

what size pot for tomatoes

Pick the Right Pot for Right Tomato Variety

Take a larger container as you can. The more room you give to your potting tomatoes to develop a strong root system, they will produce more fruits.

But when you have space limitations then you should pick a standard size of the container, that performs better for your particular tomato variety.

To identify your tomato plant height, see the seed packet instructions or tomato plant tags. Then Based on the plant’s height pick the right container size for your tomatoes.

Besides, when you going to buy containers form gardening stores or online stores, you may find the same size of containers in different dimensions.

For example, you may find 1-gallon container in different dimensions such as –

– 7″ wide × 7″ height

– 8″ wide × 6″ height

– 7.5″ wide × 7″ height

Usually determinate and dwarf tomato varieties best suit for containers. On the other side, indeterminate tomatoes best perform in the ground. However, you can grow any type of tomatoes in the pot based on the container shape and sizes.

Potting Size for Dwarf Tomatoes

Dwarf tomatoes are mainly container varieties. They can grow 6-18″ tall and need the comparatively smaller size of the container. 

Dwarf Tomato Plants HeightDimension of Containers
Width × Height
Standard Container Size
5″-6″ tall6″ × 6″½ -Gallon Pot or bigger
6″-15″ tall7″ × 7″
8″ × 6″
7.5″ × 7″
1- Gallon Pot or bigger
12″-18″ tall9″ × 8″
8″ × 7″
8.5″ × 8.5″
9″ × 8.5″
2- Gallon Pot or bigger

Potting Size for Determinate Tomatoes

The average height of determinate tomatoes around 24-48″. So, based on your plants’ height you may pick the following size of pots for your tomatoes.

Determinate Tomato Plants HeightDimension of Containers
Width × Height
Standard Container Size
18″-36″ tall10″ × 9″
10″ × 8.5″
11″ × 9.5″
11.5″ × 8.5″
3-Gallon Pot or bigger
36″-48″ tall12″ × 11″
13″ × 10″
12″ × 10.5″
14″ × 10″
5-Gallon Pot or bigger

Potting Size for Semi-Determinate Tomatoes

Semi-determinate tomatoes can grow 4-5 feet tall based on the variety. And they need the following sizes of containers.

Semi-Determinate Tomato Plants HeightDimension of Containers
Width × Height
Standard Container Size
48″-60″ tall14″ × 12″
14″ × 11.5″
14″ × 10.5″
7-Gallon Pot or bigger

Potting Size for Indeterminate Tomatoes

Indeterminate tomatoes can rise up around 5-9 feet taller or more. They need comparatively larger containers than other tomato varieties.

Indeterminate Tomato Plants HeightDimension of Containers
Width × Height
Standard Container Size
60″-72″ tall16″ × 13″
15″ × 15″
16″ × 11.5″
16″ × 12.5″
18″ × 12″
10-Gallon Pot or bigger
72″-84″ tall18″ × 14″
16.5″ × 15″
20″ × 14″
15-Gallon Pot or bigger
84″-108″ tall20″ × 16″
20″ × 14.5″
21″ × 15″
20-Gallon Pot or bigger
108″ tall or higher24″ × 16″
22.5″ × 18.5″
25-Gallon Pot or bigger

How Much Potting Soil Do I Need to Fill My Tomato Pots

The amount of potting mix exactly needs to fill up a container depends on the size of the containers and their dimensions. Besides, the actual container size also varies on the manufacturer. 

You may also face the following issues when you going to fill up your containers:

Liquid vs Dry Measurement

Potting mixes are measured in dry quarts or dry liters or a dry gallon or dry cubic foot. On the other hand, containers are measured in liquid quarts or liquid liters or a liquid gallon or liquid cubic foot.

Therefore, when you will purchase a potting soil bag to fill up a liquid gallon container then you should know some basic measurement as follows.

1 liquid gallon (U.S) = 4 liquid quarts (U.S)

4 dry quarts (U.S) = 1.16364 liquid gallon (U.S.)

1 dry quart (U.S.) = 1.10 dry liters (U.S.)

1 dry cubic foot = 28.32 dry liters (U.S.)

1 dry cubic foot = 25.71 dry quarts (U.S.)

1 liquid gallon (U.S.) = 3.4375 dry quarts (U.S.)

1 liquid gallon (U.S.) = 3.79 dry liters (U.S.)

As well, 1 liquid gallon (U.S.) = 0.86 dry gallons (U.S.)

So, a 1-gallon container doesn’t need exactly 1-gallon potting soil.

Soil Moisture and Compression

The moisture level of the potting soil also helps to determine how much potting mix required for your container. Soil moisture controls the compression level of the soil into the pot. So, pressuring the potting soil may add a 15-20 percent extra potting mix to the container.

Besides, during transplanting your tomato plants, you will also bring some soil that sticks to your plant roots. 

So, after considering the above issues I can give you an approximate idea that how much potting soil you should need to fill up your desire container.

Potting Soil Measurement for Your Plastic Nursery Pot

Container SizeStandard Dimensions
of the Container
Potting Soil Measure for Clay
Or Black Plastic Nursery Pot
(In Dry U.S. Quart, Liter and Cubic Foot)
½ Gallon6″ wide × 6″ height2.7 QT. = 2.97 L. = 0.10 CU. FT.
1 Gallon7″ wide × 7″ height
8″ wide × 6″ height
7.5″ wide × 7″ height
4.1 QT. = 4.52 L. = 0.16 CU. FT.
4.37 QT. = 4.81 L. = 0.17 CU. FT.
4.63 QT. = 5.10 L. = 0.18 CU. FT.
2 Gallons9″ wide × 8″ height
8″ wide × 7″ height
8.5″ wide × 8.5″ height
9″ wide × 8.5″ height
7.71 QT. = 8.50 L. = 0.30 CU. FT.
5.14 QT. = 5.66 L. = 0.20 CU. FT.
7.2 QT. = 7.93 L. = 0.28 CU. FT.
7.97 QT. = 8.78 L. = 0.31 CU. FT.
3 Gallons10″ wide × 9″ height
10″ wide × 8.5″ height
11″ wide × 9.5″ height
11.5″ wide × 8.5″ height
10.54 QT. = 11.61 L. = 0.41 CU. FT.
10.03 QT. = 11.04 L. = 0.39 CU. FT.
13.37 QT. = 14.72 L. = 0.52 CU. FT.
13.11 QT. = 14.44 L. = 0.51 CU. FT.
5 gallons12″ wide × 11″ height
13″ wide × 10″ height
12″ wide × 10.5″ height
14″ wide × 10″ height
18.51 QT. = 20.39 L. = 0.72 CU. FT.
19.8 QT. = 21.80 L. = 0.77 CU. FT.
17.74 QT. = 19.54 L. = 0.69 CU. FT.
22.89 QT. = 25.20 L. = 0.89 CU. FT.
7 Gallons14″ wide × 12″ height
14″ wide × 11.5″ height
14″ wide × 10.5″ height
27.51 QT. = 30.30 L. = 1.07 CU. FT.
26.23 QT. = 28.88 L. = 1.02 CU. FT.
24.17 QT. = 26.62 L. = 0.94 CU. FT.
10 Gallons16″ wide × 13″ height
15″ wide × 15″ height
16″ wide × 11.5″ height
16″ wide × 12.5″ height
18″ wide × 12″ height
38.83 QT. = 42.76 L. = 1.51 CU. FT.
39.34 QT. = 43.33 L. = 1.53 CU. FT.
34.46 QT. = 37.94 L. = 1.34 CU. FT.
37.29 QT. = 41.06 L. = 1.45 CU. FT.
45.51 QT. = 50.12 L. = 1.77 CU. FT.
15 Gallons18″ wide × 14″ height
16.5″ wide × 15″ height
20″ wide × 14″ height
52.97 QT. = 58.33 L. = 2.06 CU. FT.
47.83 QT. = 52.67 L. = 1.86 CU. FT
65.57 QT. = 72.21 L. = 2.55 CU. FT
20 gallons20″ wide × 16″ height
20″ wide × 14.5″ height
21″ wide × 15″ height
74.83 QT. = 82.40 L. = 2.91 CU. FT.
67.89 QT. = 74.76 L. = 2.64 CU. FT.
77.4 QT. = 85.23 L. = 3.01 CU. FT.
25 gallons24″ wide × 16″ height
22.5″ wide × 18.5″ height  
107.74 QT. = 118.65 L. = 4.19 CU. FT.
109.54 QT. = 120.63 L. = 4.26 CU. FT.  

The above table will give you an approximation that how much potting soil needed for growing tomatoes in a single container. However, the volume of potting mix may change due to the change of the container dimension.

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John Michael
John Michael is a self-help writer and a hobby gardener. He has a bachelor's degree in Library Science. Michael’s passion in writing is to inspire the beginner gardeners to not just “hang in there” or “make it through” but to thrive. He does this through blogging at ofags.com. He began writing in 2017.

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