Here’s how to prune tomato plants to get the biggest harvest you can. To begin with, there are two times to consider pruning tomato plants – the first is during the season to shape the plant growth and the second is to prune late in the season to encourage ripening and increase yields.
Shaping the growth of determinate plants that are being left to sprawl on the ground is a thankless task. Don’t bother.
Pruning Depends On How You Grow Your Plant and Why
You will get more fruit per plant if you allow your plants to sprawl – both in determinate and indeterminate varieties.
You will get more fruit per square foot of garden if you stake your plants and grow them upright.
One system is excellent for big gardens and the second better for small gardens. Cages are an intermediate method that can be used by either. But if you’re really big or really small, you’ll make things easier by adopting one or other of the two above.
The pruning systems below are obviously for the staked plants. Sprawled plants are not pruned at all.
All Season Pruning
Indeterminate plants – those that produce fruit all season long – produce more if one or two main stems are allowed to grow and side shoots (called “suckers”) are pruned off weekly. A sucker begins life as a small shoot growing from a leaf axil (where a leaf meets the stem) and will quickly take on a life of its own growing into another main stem if allowed to remain.
Staking an indeterminate plant and pruning it to a single stem will produce very large harvests of the highest quality fruit.
Late season pruning
Late season pruning to increase yields is as simple as cutting off the growing tip of the staked tomato and continuing to remove suckers right up to frost. If you don’t allow the plant to grow new shoots, it turns its energy to ripening existing fruit. This is an old greenhouse technique for increasing the late crop and if you pinch the tips off six weeks before the killing frost, you’ll get those last few tomatoes big enough to harvest and ripen indoors.
The last pruning tip is to remove all leaves below the fruit truss that has just been harvested. This increases air circulation and those lower leaves are usually shaded by this time of year and not adding to the growth rate of plants.
You may find them starting to yellow and get a leaf spot fungus. Removing them is garden cleanup and recommended.
But only below the currently ripening fruit truss – not above.