When you start shopping for tomato plants, you’ll usually see on the label that the tomato is either determinate or indeterminate. This designation makes a big difference in the kind of harvest you’ll get and also how you’ll grow the plants.
With determinate tomatoes, once the plant gets to a certain size, the growing tip of the vine(s) will stop producing new stems and leaves and will instead produce a cluster of flowers called an inflorescence. Because the tip of the vine now ends in an inflorescence, there’s no more growth and plant won’t get any taller. Once that terminal flower cluster has formed, the plant puts all of its energy into ripening the tomatoes that have set on the vines.
Because of this, determinate tomatoes tend to produce a big harvest over a shorter period of time. In my experience, while the biggest harvest is over a few week period, I’ve always a few tomatoes to harvest for at least 6 weeks. If you’re looking to preserve tomatoes, determinates are great because you get a large harvest in a short period of time.
Indeterminate tomatoes are different. In these plants, the growing tip never end in an inflorescence; they just keep growing. These plants produce tomatoes at a steady rate throughout the season. If you’re only growing a couple of tomato plants and want fresh tomatoes through the growing season, indeterminate tomatoes are the way to go.
While both types of tomatoes grow in the same conditions, the growth habits are very different. Determinate plants will get no more than 3-4′ tall and they can easily be grown in tomato cages or left to grow on the ground. Indeterminate tomatoes become very large plants because they just keep growing taller and taller. I grow the indeterminate grape tomato “Juliet” and by the end of the growing season it’s always more than 12′ tall! If you grow indeterminate plants you’ll need to stake them or grow them on a tall trellis – a little tomato cage won’t be able to contain these huge plants.
I grow both types of tomatoes. This year I have plants of “Pony Express,” a saladette tomatoes for canning and making sauce. These are determinate and I’ll be growing them in tomato cages. I also have a couple of grape tomatoes, “Juliet” and “Gold Nugget,” both of which are indeterminate. I’ll be growing these on the frame of an old swing set which will let them to grow as big as they want.