When it comes to growing tomatoes in containers, one of the most important decisions is choosing the right size pot or planter. The container size affects the tomato plant’s root development, nutrient and water intake, and ultimately the plant’s productivity. So what is the ideal container size for growing healthy, productive tomato plants? Let’s take a look at the factors to consider when choosing containers for your tomato crop.
Tomato Plant Root Structure
Before we can understand what tomato plants need in a container, we need to look at how they grow. Tomato plants have a deep central taproot that goes downwards and a large network of lateral roots that spread out horizontally. As the plant grows older, the roots get deeper and wider.
Tomato plants need the right amount of depth and width in their pots for root growth. Restricted roots mean stunted plants. Tomato roots also need plenty of oxygen. When it rains or waters, a container that is too small keeps the water in for too long, denying the roots oxygen. Roots that aren’t fully developed have a hard time taking in water and nutrients, which slows growth and lowers yields.
General Container Size Guidelines
A container for one tomato plant should have a minimum depth of 12 inches and a minimum diameter of 12 inches. This makes a surface area of about 1 square foot and gives roots plenty of room to spread outward and downward.
For cherry or patio variety tomatoes, which are smaller, a 10-12 inch pot is usually sufficient. For full-size indeterminate tomato varieties, which grow larger and produce fruit all season, a 15-25 gallon container is better to accommodate the more expansive root system.
The bigger the container within reason, the better More space reduces watering frequency and provides insulation from temperature fluctuations Just ensure adequate drainage holes in the bottom to prevent waterlogging.
Factors Determining Ideal Tomato Container Size
Several factors determine the optimum container size for your specific tomato plants:
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Type of tomato: Determinate (bush) tomatoes are smaller than indeterminate (vineing) tomatoes, so their roots don’t need as much space. Also, dwarf and patio plants need smaller pots than full-size plants.
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Number of plants – If planting multiple tomato plants per container, scale up the container size to provide adequate space. For example, a 30-35 gallon container could hold 3 plants.
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Climate – In hot, dry climates, use larger containers to retain more moisture between waterings. In cool climates, use smaller containers to retain heat better.
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Available space – Consider available space when choosing container sizes. Compact patios may dictate smaller pots versus a spacious garden allowing large planters.
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Container material – Use larger containers if your pots are dark materials that absorb heat, as tomato roots prefer cool conditions.
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Watering frequency – Larger volumes of soil stay moist longer, extending time between waterings. Frequent travelers may prefer fewer, larger containers.
Ideal Pot Sizes for Different Tomato Varieties
Based on tomato type, here are some more specific container size guidelines:
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Cherry tomatoes – 10-12 inch diameter, 12 inch deep container
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Patio/dwarf tomatoes – 10-12 inches deep, 12-15 inches diameter
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Determinate (bush) – 15-20 gallon container, minimum 12 inches deep
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Indeterminate – 20-25+ gallon container, minimum 15 inches deep
If you want to push your harvest potential, you can plant two determinate tomatoes or one indeterminate tomato per 20-25 gallon container. Just ensure even spacing between plants.
Caging or Staking Tomatoes in Containers
With the exception of dwarf varieties, tomato plants in containers require support to keep them upright as they grow. Staking or caging options include:
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Tomato cages – Wire cages 18+ inches diameter and at least 4 feet tall for most varieties
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Bamboo stakes – Use 5-6 foot stakes for indeterminate tomatoes
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Wooden stakes with gardening twine – Crisscross twine between stakes around plants
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Trellises – Install trellises behind containers to support plants as they vine upwards
Match your staking method to the tomato variety and container size. Indeterminate tomatoes in larger containers will likely require sturdy staking options like bamboo or wooden stakes and trellising.
Choosing the Right Container Type
In addition to size, consider these factors when selecting tomato planters:
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Drainage – Containers must have drainage holes to prevent waterlogging. Self-watering containers work well too.
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Weight – Once filled with soil and mature plants, larger containers can get very heavy. Use containers with wheels if they need moving.
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Material – Avoid black plastic containers that absorb too much heat. Look for lightweight ceramic, wood, or resin containers.
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Self-watering planters – These maintain ideal moisture levels, minimizing watering needs. EarthBoxes are a popular self-watering container option.
Start Tomato Plants Off Right
To ensure your container tomatoes get off to a great start:
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Use a high-quality potting mix designed for vegetables. It should be loose, fertile, and fast-draining.
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Add a slow-release fertilizer or compost/manure blend to provide nutrients all season.
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Amend planting holes with extra compost or fertilizer to fuel early root growth. Side dress plants with fertilizer monthly.
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Use transplants instead of seeds to get a head start on the season. Harden off transplants before planting.
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Water newly planted tomatoes daily until roots establish, then 2-3 times a week depending on size.
By selecting the right sized container and caring for plants properly, you can grow abundant tomatoes on your patio or porch this season!
How Deep and Wide Should the Garden Container Be?
Dwarf varieties aside, the bottom line is that each tomato plant needs roughly one square foot to grow. So, a 12-inch diameter garden container will work for most tomato plants.
Depth is another consideration relating to container size. Tomato plants root at a medium depth, so they need one at least 12 inches deep.
If you want to grow indeterminate tomato varieties, youll likely want to scale up with your garden container. These varieties typically grow nearly twice as large as their bush tomato counterparts.
Here, you may need a garden container up to 24 inches deep with a similar diameter.
If you prefer thinking about planter capacity, here are some guidelines:
- Determinate tomatoes: 5-gallon pot or larger
- Indeterminate tomatoes: 15-gallon pot or larger
Why a Bigger Container is Generally Better for Tomatoes
Independent of variety, you may want to choose a larger container from the get-go for your tomato plants. It presents some advantages:
- Root Development: Roots have more room to grow in a bigger garden pot. The better the root system, the healthier your tomato plants. And the healthier your tomato plants, the bigger your harvest. Roots that grow well also help keep diseases like blossom end rot at bay.
- Moisture Retention: It makes sense that bigger garden pots can hold more water. That’s great for tomato plants because they need to be watered often. It also takes less effort and time to water plants.
- Stability: Tomato garden boxes that are bigger are more stable than ones that are smaller. Tomato plants can grow up to six feet tall, which is pretty big. With that wider base, your tomato plants won’t be able to fall over.
So, if you’re torn on how big your container must be for your tomatoes, size up.
7 Best Tomatoes to Grow in Containers
FAQ
Do tomatoes prefer deep or wide pots?
Tomatoes are vigorous growers that need lots of room for roots to spread out. Containers should be at least 5 gallons or 12 inches wide and deep, though bigger is better. For maximum production, containers that are 10 gallons or larger are ideal, especially for bigger tomato varieties.
How big should a container be for a tomato plant?
For tomato plants in containers, a good starting point is a 5-gallon pot, but larger is often better. For determinate (bush-type) tomatoes, a 5-gallon pot or larger is recommended. For indeterminate (vining) tomatoes, which grow larger, a 10-gallon or larger container is ideal.
Is a 5 gallon bucket big enough to grow a tomato plant in?
Planting tomatoes in 5-gallon buckets is a great option if you don’t have much garden space. Begin by making at least a dozen holes in the bottom of the bucket so that water can drain easily. You can use a drill with a 3/8” bit, or a hammer and nail.