They say there’s a sucker born every minute and it sure seems that way on tomato plants. Suckers are the new growth that sprouts at the intersection of a branch and the main stem of a tomato plant, and the long-standing advice has been to remove them by pruning or pinching them out.To not do so is at your peril because it’s believed suckers steal energy from the plant. At least that’s the belief, except it’s not so. It’s one of those things that’s been done by gardeners forever because someone, somewhere, thought it was a good idea and no one thought to question it.
What is a sucker? On a tree, it refers to those fresh shoots that appear at the base of a tree. On a tomato plant, there are none. What are referred to as suckers are simply secondary branches, and with their leaves they contribute energy to the plant rather than steal it. These secondary branches will also develop flowers and fruit
So why have gardeners been removing them? First, we have to understand the two main types of tomato plants, determinates and indeterminates. Determinates were initially bred for commercial growers. This type grows only to a limited size and the fruit ripens more or less at the same time, making it much easier for mechanical harvesting. When grown as a large-scale commercial crop, determinate plants are not staked or supported, and you can be sure no one roams thousands of acres of fields, pinching off anything in sight that looks like a so-called sucker.
These smaller, bushier plants are suitable for the home gardener with limited space as they can be easily supported if need be with tomato cages, in ground or in a planter, so why bother with pinching off suckers if the commercial growers don’t bother — I’m getting to it . . .
Prior to the development of determinate varieties, most of the plants gardeners were growing in backyards in the old days were indeterminate plants. We still grow them, and many are heirloom varieties. They’re called indeterminates because they don’t stop growing. Tomato plants are vines and will grow that way when allowed, and for as long as conditions are suitable.
Indeterminates are also the type most often grown as hot house tomatoes in commercial greenhouses. There, they are allowed to grow and produce fruit throughout the season, ensuring a continuous supply for the market. In greenhouse production, the lower leaves are sometimes removed, mainly for hygiene purposes as disease can strike where the humidity is highest. Otherwise the vines are allowed to grow naturally and become a jungle of hanging fruit.
In the backyard, however, where the season is shorter, indeterminates won’t reach the size of the greenhouse plants, but they do need serious staking, with a large cage or strong stakes. And this is where the reason for pinching out the “suckers” probably began. With secondary branches shooting off in all directions, there’d be a need for even more support. By restricting the plant to a main stem, it made sense and was much easier to train the plant. Consequently, the habit of sucker pinching took off and it continues today.
If you need to keep your indeterminate plants under control, go ahead and remove any secondary branches that aren’t required, but don’t feel it’s essential to remove them all. Some like to remove lower branches to improve airflow or keep leaves off the soil. Otherwise, the question is, does it really make any difference?
The answer is yes — sort of. If you leave the secondary stems on the plant, you’ll likely harvest far more tomatoes than you would if you removed them, except they might be a tad smaller than the ones from a plant that had the suckers removed.
So there you have it, to pinch or not to pinch the suckers? The choice is yours. You’ll still get tomatoes.