Tomatoes are easily grown in containers. As anyone who has seen volunteer tomatoes sprout from just about anywhere the seed can find a footing can testify, they are tough plants.
We have grown them in containers that hang upside down and old 5 gallon buckets. We’ve also heard of folks that buy a bag of topsoil, cut a hole in it and plant their tomatoes in that and nothing else. When growing them in containers, there are three things that you need to keep in mind- container size, feeding and watering.
Container size is important for a couple of reasons. Tomato plants need some room to spread their roots. In the ground, their roots can reach three to four feet into the soil and the same distance on either side of the plant.
They also are heavy feeders and users of water. Also, depending on the type of tomato, the plants can get to be quite large. For this reason, the smallest container size that we recommend is something with a soil capacity of four or more gallons. A container of this size will have sufficient weight and water holding capacity.
Soil for growing tomatoes in a container should have a generous amount of composted organic matter to help with feeding and to help retain moisture. The blend of soil will change depending on how you grow your plants. Hanging tomato containers need to have light-weight soil mixes. The weight of a fully grown tomato plant, its fruit, and the soil when watered can be quite heavy.
For this reason also, you need to have a sturdy support system for the hanging container. Containers that sit on the ground, on the other hand, need a little more weight so that the plant doesn’t become top-heavy, especially if you have any sort of trellis, stake, or tomato cage for supporting the plant.
Due to the limited space in containers, the availability of water and nutrients becomes an issue. Most containers need to be watered daily, sometimes more during dry hot periods. With this much watering, loss of nutrients can be an issue.
Having sufficient organic material in the soil mix will help buffer the effect, but additional, regular feeding throughout the season is necessary. Use a fertilizer with higher Phosphorus and Potassium (P-K) numbers than Nitrogen (N) to stimulate fruit and root growth. Using too much nitrogen will encourage plant growth at the expense of fruit production.
The term container can be expanded to include larger non-mobile planters. More like raised beds than containers, these larger devices can be built from practically anything.
Wood, concrete blocks, bricks, tires, corrugated metal and landscaping timbers are some of the things that can be used. They can be placed on dirt that may have been contaminated or even solid surfaces such as concrete or asphalt.