Guide to Pruning Tomato Plants
See you later, Sucker!
Have you planted your tomatoes and now that they’re growing, they’re all over the place and out of control? Did you know that you’re supposed to prune them? But wait, not all of them. And some people say not to at all, ever. Is this confusing yet?
TYPES OF TOMATO PLANTS
First , we need to know that there are two types of tomato plants: Determinate and Indeterminate. You need to know the difference because it will determine (*wink*wink*) what you do with them.
Determinate tomatoes are bush type plants. They typically max out at 4 feet tall and will only produce fruit for a few weeks. Then they’re done. That’s not necessarily a bad thing though. A lot of great determinate tomato varieties are great for cooking.. Ie. busting out Grandma’s iconic gravy recipe, then can that good stuff! They’re also great for small space and container gardening. My (Italian) husband’s favorite paste tomato is Roma, which is determinate.
Indeterminate tomatoes are vining type plants that grow, and grow, then grow some more, some up to 12 feet. They will continuously produce fruit up until the first fall frost. Because of their size, they’re better suited to planting in the ground with a fair amount of space. Vining tomatoes also need a sturdy system to keep them upright. There are MANY variations on staking and trellising indeterminate tomatoes, which we can talk about in a separate post.
I will say one thing about containing those branches: You know those round tomato cages you see at the stores? Indeterminate tomatoes laugh at them. Useless things. However, you can use the larger tomato cages for determinates. Just save the little cages for your peppers.
To Prune, or Not to Prune? That’s a Sucky Question.
Now that we have that out of the way, let’s talk SUCKERS.
The tomato plant is made up of the root, stem, leaves, flowers, fruit, terminal end (the part that keeps growing at the top), and what’s commonly known as suckers. Suckers seemingly sneak out of nowhere and can make you say “what in the world happened here!?!?!” in just a matter of days. They grow out of the “arm pit” between the leaves and the stem to create an entirely new stem with its own leaves, flowers, fruit, and terminal end.
Why are suckers bad? They’re not always. In the case of the bushy determinate tomatoes, they’re good. Those plants aren’t getting that big in the first place, and they need all the flowers they can grow to produce fruit. Got determinates? Conventional advice is DON’T PRUNE THEM.
On the other hand, suckers on indeterminate plants can get out of hand quickly. Most people say if your plant is focused on making more and more separate stems, it has less energy to focus on growing flowers and fruit on the main stem. Pruning the suckers also keeps the plant neater, and easier to to stake or trellis.
Some people suggest not pruning the suckers off any of their plants, stating it doesn’t make a difference. I can personally see both sides of the argument.
However, letting those indeterminates grow willy nilly makes for a wild garden! I personally prefer to allow a couple suckers per plant to grow and prune the rest (and there will be PLENTY left to prune). I feel like the plants just get hard to manage if you don’t prune any of them and my garden doesn’t have enough room to grow a tomato jungle.
How to prune
Inspect your plants. Look at the area between the main stem and a leaf.. we call that the “arm pit”. If you see a little stem and leaves growing, just snap it off with your fingers. If it’s a little bigger, I like to use my fingernail to get a cleaner snap. Once it’s too big for a quick snap, you should grab your clean pruning shears or scissors. If a sneaky sucker gets away from you and is well on it’s way to producing flowers and fruit, just leave it alone. Pruning large suckers can stress out your plant.
It’s really as easy as that.
I like to go out in the garden in the morning to check my plants, which gives me not only a few moments of quiet, but gets that first morning sunlight on my face, which is great for your circadian rhythm!
I almost forgot. What to do with those suckers? You can grow new plants from them! Tomato plants will grow roots anywhere along them stems.. If they’re big enough, you can simply stick them in water (or soil).
Once your sucker grows roots, carefully transplant it to the garden.
You’ve just grown a whole new plant. Tada!!
Personal experience.. Don’t do what I did.
Here’s the rub. You don’t always know what you’re getting when you’re standing at the garden center among 94958385 varieties of tomato plants because determinant and indeterminate are not always indicated on the tag. Make sure you have an internet connection while you’re there to look them up, or know what you want before you go (and then hope they have what you’re looking for).
Case in point, this year I purchased a bunch of tomato plants at our local nursery. Some were labeled indeterminate vs determinate and I honestly didn’t think anything of the plants without that information on their tags. I get home and start to prune the suckers as they’re getting bigger (before transplanting outside). Go to plant them outside and do a quick Duck Duck Go on the varieties. Womp Womp! Some of them were determinant! They’re still growing, but I probably sacrificed some of my precious plum tomato haul because I just didn’t double check.
Grow Better When You Know Better – Until then, do your best!
Summary
Determinate tomatoes:
- Bushy plants that grow up to 4 feet high
- Produce fruit around the same time, then die
- Don’t prune
Indeterminate tomatoes:
- Vining plants that can grow up to 12 feet high
- Produce fruit until the first frost
- Prune the suckers
Pruning:
- Suckers grow out of the “armpit” between the stem and leaves
- Snap them off while they’re still small
- Plant larger suckers in soil to grow a new plant