To Prune or Not to Prune?

You have to prune vining tomato plants if you want to really maximize your harvest, but everyone seems to have their own method for how to prune "correctly". When it comes to suckers, gardeners hold some pretty strong opinions. Get rid of them. Absolutely do not touch them. They’re bad for your plant! They’re key to a bigger harvest!

Let's first talk about what a sucker is, and then we'll look at why you might prune them and why you wouldn't. Lastly, I'll tell you what I do every season to grow beautiful and productive tomato plants.

What Are Tomato Suckers?

Suckers are that extra little vine that starts to grow on vining tomato plants. They're actually capable of becoming an entirely new plant if you were to root them—just another incredible way that plants have to multiply themselves.

Suckers emerge from what I like to think of as the elbow of the plant—that junction where a leafy branch meets the main stem (called the axil, if you want to get technical). To spot a sucker, look for the point where a vertical stem and horizontal leafy stem meet at a 90° angle. The third stem growing at a 45° angle is a sucker.

So Are Suckers Good or Bad?

Most gardeners consider suckers undesirable because they suck some of the plant's energy. I personally don't think they suck at all, but I'll get to that in a bit. (Sorry if the kids are reading. Don't say "suck", kids. Only mommies can say that.)

Even though lots of gardeners will tell you to just prune the suckers, it's actually a little more nuanced than that. So that brings us back to our dilemma: To prune the suckers or not to prune the suckers?

I'll tell you what I do, but first I want you to figure out what you think is best for you! All you have to do is answer one question.

Do You Want Bigger Tomatoes or More Tomatoes?

Here's the deal: If you prune the suckers, you'll get bigger tomatoes. If you don't prune the suckers, you'll get smaller tomatoes—but a lot of them.

Bigger Tomatoes

You’ll end up with fewer tomatoes overall by removing the tomato suckers. But the fruits your plant produces will grow to a larger size if left to reach full maturity. That's because your plant will only have to focus its energy on one main vine and can send lots of resources to each piece of fruit so they can grow nice and big. You'll also get fruit a bit earlier.

More Tomatoes

If you leave the suckers on the plant, those suckers will turn into more vines. More vines mean more flower clusters and, eventually, more fruit. Each vine needs water and nutrients from the plant, so your plant won't have enough energy to spend on making each fruit really big. Overall, tomatoes will be smaller. But, like I said, there will be more of them, and you'll also enjoy a longer fruiting period.

I Leave the Suckers on My Tomato Plants

It's up to you whether you prune suckers or leave them.

For years, I pruned all the suckers because the gardeners I was following online told me to. I did end up with some really nice, juicy tomatoes. It's just that I had so much riding on those few beautiful pieces of fruit. Will the squirrels steal them before they're fully ripe? Will the hornworms nibble on them? Will they ripen in time?

I felt like I was hedging all my bets on a just a few tomatoes that I wanted to get really big.

It finally occurred to me that I didn't actually care how big my tomatoes were. I just wanted a lot of them—so many that if the squirrels or birds took a couple, it wouldn't make much of a difference. My priority is to have a continuous supply of small fruit throughout the growing season.

The best method for me, therefore, based on my goal, is to leave the suckers. So that's what I do.

Before the gardening rule-followers get all up in arms, I want to say that I do prune my tomato plants, okay? I do prune! I just don't prune the suckers.

I'll tell you what I do instead to get a continuous supply of fruit from very healthy tomato plants, suckers and all.

How to Prune Tomatoes for a Continuous Supply of Fruit

Pruning is really important to most plants you'll grow in the kitchen garden, but especially so for vining tomatoes. Tomato plants need good air circulation around their leaves or they'll fall pray to a range of viral, bacterial, and fungal disease. Pruning is the best way to get lots of sunlight and air flow on and around each leaf.

Beyond increasing plant health, pruning is also a way to tell your plants what you want from them. If you let the plant grow on its own, the plant may just keep producing more stems and leaves instead of flowering or fruiting until the season has nearly come to an end. Pruning is your way of telling the plant you want less of that (leaves) and more of this (flowers and fruit), please and thank you.

Follow these steps to prune your indeterminate tomatoes.

STEP ONE TO PRUNE INDETERMINATE TOMATOES

Think of your vining tomato plant as a mini tree. You don’t see many mature trees with a lot of trunks. There’s usually a thick main trunk, and all the rest of the plant’s extensive growth stems from that one source. 

So, the first goal of your pruning is to pick one main stem within two to three weeks of planting. If your plant branches out at the base, select the largest stem to be the main provider and cut the others at their base with a clean pair of pruners.

Prune back any new stems that sprout from the base of the plant throughout the growing season.

STEP TWO TO PRUNE INDETERMINATE TOMATOES

Prune all leaves and stems below the first flower when it appears. This tells your plant you'd like it to spend more energy on producing more flowers and less energy on growing more leaves.

While leaves are critical for plant health, we want to keep the fewest amount of leaves possible. Each leaf is something that needs support, water, and other nutrients from the plant, and you’d rather have your plant spend those resources on more flowers and fruit than more leaves. 

STEP THREE TO PRUNE INDETERMINATE TOMATOES

Every two weeks, prune the lower leaves on the vine, removing about a third of the plant’s leaves. Instead of pruning the suckers, you want to prune away non-producing stems and leaves so that the plant can focus on lots of fruit production. Basically, if a branch doesn't have any flowers forming, it needs to go. What that means is you often end up cutting the branch that's right next to the sucker.

You’ll also want to cut away any leaves that are discolored or spotted or that have holes or tears in them.

STEP FOUR TO PRUNE INDETERMINATE TOMATOES

Your final goal will be to prune to encourage your plant to stop producing new fruit and to start ripening the fruit already on the vine. This process is called “topping” because you’ll prune the top of the plant. Through topping, you tell the plant to slow the energy placed on creating more vines and leaves and accelerate the energy for ripening the fruits. The best time to do this is about 2 to 3 weeks before the season changes.

But What About Bush Tomatoes?

You only need to worry about pruning if you're growing a vining type, aka an indeterminate tomato. Bush tomatoes, or determinate tomatoes, are basically self-pruning because they're meant to only grow to a certain size and then stop. This is not the type of tomato we're talking about when we debate pruning the suckers.

So if you bought a tomato that says "bush", "patio", or "determinate", you don't really need to prune your plant at all.

Make sure you know which type of plant you're growing so you can make the best decisions about how to support it and prune it.

You Can't Go Wrong With Pruning Tomato Plants As Long As You Do Prune

I recently posted a video about not pruning suckers, and I got tons of comments like “This goes against everything I’ve been told about pruning tomatoes.”

This is another example of how there really are no rules in gardening. Have some fun, do a little experimenting, and see which method works best for you. You can't really go wrong as long as you do some kind of pruning on your indeterminate tomato plants. Either cut all the suckers and get big fruit, or cut the non-producing stems, leave the suckers, and get more fruits.

To me, each sucker is a promise of more fruit, and to just cut that off would, quite frankly, suck! (Again, sorry, kids!)

But it doesn't matter what I think. You get to decide if you're on team More Fruit or team Big Fruit. May the fruits of your labor be delicious no matter which team you're on!