Determinate vs. Indeterminate Tomatoes
Whenever you start reading about growing tomatoes in pots, you’re almost certain to start encountering talk about determinate and indeterminate tomatoes. What do these terms mean? What can you expect from a determinate tomato, or an indeterminate one?
The simplest answer is that determinate tomatoes set their fruit all at once, whereas indeterminate tomatoes continue to grow and produce fruit until they are killed — usually by frost.
This definition has some other implications, however, which need to be considered.
If you watch the growth of determinate tomatoes, you’ll see a set pattern: the tomato plants grow until they reach a certain size. Then, all at once, the plant flowers. Flower occur at the tips of stems, ending growth. Then the flowers fruit, and ripen. There are some determinate tomatoes, called “vigorous determinate”, that will produce a second crop if you prune them back after the first harvest is done. Celebrity is probably the most well-known of the vigorous determinate varieties.
Indeterminate tomatoes, on the other hand, produce flowers and fruit steadily throughout the season. Branches form flowers along the side, so new growth continues constantly from the end of the vines. Because of this, the fruit crop is slower and steadier.
Because of their pattern of growth, determinate tomatoes grow very well in containers. They do not grow out of control, and require less staking than indeterminate varieties. However, if what you want is a steady supply of tomatoes for salads and the like, determinate tomatoes probably won’t suit your needs. The extra work of container growing indeterminate tomatoes may be worthwhile in that case.
So, if you want to grow indeterminate tomatoes in a container, what do you need to do?
Well, the first step, as always, is to choose the container. Choose large, for indeterminate tomatoes: 6-7 gallons, to support a large plant.
Install a cage when you plant the seedlings, and make sure it is tall: some indeterminate tomatoes will grow to six or seven feet tall.
As tomato vines reach outside the cage, tie them to the cage or prune them off. You need to check the growth, because it will eventually get out of control otherwise. I talk a bit more about pruning in 7 Tips for Great Tomatoes.