20170708A.jpg
This growth is not a sucker, but a stem… and you don’t have to remove it.

I’ve written about this subject before, but I keep getting so much feedback on the subject I figure the information is worth repeating. And what I’ll try to get across here—hopefully more clearly this time around—is that you don’t necessarily need to remove tomato suckers … and, in fact, you can’t, because tomatoes don’t produce suckers. And you can’t remove something that doesn’t exist, can you?

Definitions

A sucker is, by definition, a stem that never produces either flowers or fruits. Logically, you’d want to remove suckers from your tomatoes if they had any.

The thing is, though, they don’t. Those green stems that start to form at leaf axils (see the photo above) are not suckers, they’re simply secondary stems. Branches if you prefer. Left to grow, they will produce both flowers and fruit… and therefore aren’t suckers. Studies show that tomatoes whose side stems are left in place produce more fruit than ones whose secondary stems are removed, although the fruit may be somewhat smaller. Still, there is a net gain in total tomato production by weight, so you get more “tomato” to eat by not pruning… sometimes considerably more.

Suckers Drain Energy, Stems Provide It

20170708H Allthingsclipart
Bloodsuckers suck the life out of fish, but tomato “suckers” are not only harmless, but beneficial. Illus.: Allthingsclipart

It’s important to understand that, as the word “sucker” is clearly pejorative. When you hear it, you automatically imagine the sucker stealing energy from the plant. It sounds like something you should get rid of. On the other hand, the word “stem,” the true term, is a neutral word, neither negative nor positive. You have to ask yourself what is the advantage of removing a stem from a tomato plant.

And here’s the really important point: since stems produce leaves and leaves carry out photosynthesis, stems don’t “suck” the energy out of the plant. Instead, they provide energy. All the energy of most plants comes from photosynthesis and photosynthesis is carried out by the green parts of the plant. Since these secondary stems are not only green, but bear leaves, they add considerable energy the plant can use to grow more vigorously and produce more fruits.

Yes, tomato plants will actually be stronger and grow more vigorously if you don’t prune off the secondary stems. It’s as simple as that!

Why Then All the Insistence on Removing “Suckers”?

Generations of gardeners have been taught that removing secondary stems from tomatoes is important. In fact, the practice is now so firmly entrenched that most people just do it, without ever questioning why. But there is a reason people first started doing it… and here it is:

20170708C tomatodirt.com.jpg
Tomatoes are pruned so they are more amenable to growing on a stake. Photo: tomatodirt.com

When a tomato plant is grown on a stake in order to keep it from sprawling rather than on a trellis as had been the method used before the 20th century, there is a limit to the number of stems that can be attached to the support. Our ancestors decided to remove the secondary stems in order to better attach the plant to its stake. If you use a single stake, traditionally you’d keep only the main stem and remove all the others. If you use two stakes (a fairly common technique), a second stem is allowed to grow and produce fruit while all others are removed.

So, the reason behind removing secondary stems never had anything to do with improving the harvest, but rather was strictly a question of staking the plant in a logical manner.

20170708D Hort.jpg
Caged tomatoes need no staking, yet produce more tomatoes!

When tomato cages first began popular towards the end of the 20th century, that changed the situation. As they support the plant on all sides, removing the secondary stems is no longer necessary: there is a structure around the whole plant that can hold up even the lankiest stem. As soon as any stem starts to grow outside of the cage, simply push it back inside. It couldn’t be easier! Except that most gardeners continue to remove secondary stems even on caged tomatoes without even asking themselves why.

Of course, typical tomato cages are designed for determinate tomatoes, which are relatively small plants. To support an indeterminate tomato, like the popular and very vigorous cherry tomato ‘Sweet 100’, a huge plant with multiple stems, takes a large tomato cage. They are less common, but they can still be found in better garden centers or you can make your own.

So there you go: if you’re using an appropriately sized tomato cage, you no longer need to remove any secondary stems.

The Advantage of Pruning Secondary Stems

20170708E onlytomatoseeds.com.jpg
To grow giant tomatoes, choose a large-fruiting variety and let only one fruit mature per plant. It will be H U G E! Don’t prune off secondary stems, instead just pinch off all but one flower. Photo: onlytomatoseeds.com

There is, however, one advantage to removing secondary stems. As the plant will now produce less fruit, it will put a little more energy into its reduced crop and each fruit will be slightly larger.

The Advantages of Not Pruning Secondary Stems

20170708E Eng.jpg
Unpruned tomatoes produce slightly smaller but far more numerous fruits, often twice as may as a pruned tomato. Original photo: simplyfreshdinners.com

If you don’t remove secondary stems, you will usually harvest about twice as many tomatoes, although they will be slightly smaller than the tomatoes produced by a pruned plant. On the other hand, they often taste better because the plant has more leaves and therefore more energy… and leaves convert solar energy into sugar.

Also, pruning tomatoes leaves a wound that harmful microbes can use to penetrate your plant, something you avoid if you don’t prune. If you do decide to remove the secondary stems, make sure you sterilize your pruning shears between each cut. It’s very easy to accidentally transmit diseases, notably viruses, from one tomato plant to another.

Obviously, though, the biggest advantage of not removing secondary stems is simply that it requires less effort. Long live laidback gardening!

A Few Misconceptions About Pruning Tomatoes

Some gardeners claim that letting all the branches grow will delay the harvest, but in fact, it really has no effect on maturation. The variety of tomato, the growing conditions, the weather and other factors do influence the speed at which tomatoes mature, but not pruning. An unpruned tomato plant will produce fruits as quickly as a pruned plant, sometimes more quickly. After all, it has more energy to put into it.

20170708F Scot Nelson, Flickr.jpg
Removing too much foliage from a tomato plant can cause sun damage to the fruit. Photo: Scot Nelson, Flickr

Other people claim that tomato fruits must be exposed to the sun in order to ripen and therefore on a pruned plant, with reduced foliage, the fruits will be less likely to be hidden by foliage and thus the fruits will ripen faster. But in fact, this is not the case either: even fruits that are completely hidden by leaves ripen perfectly well. It’s the leaves that must be exposed to the sun, not the fruits. Worse, fruits suddenly exposed directly to full sun as a result overzealous pruning can suffer from sun scald and becomes essentially unusable.

The gardeners in cold climates often insist they have to prune their tomatoes that because of their short growing season. They’re convinced that tomato plants whose secondary stems are removed will mature more quickly. I repeat, the more green leaves a tomato plant has, the more energy it will have … a big advantage when your growing season is short.

(There are ways to get tomatoes to mature more quickly in short season climates, notably by choosing extra early or cold-resistant varieties, growing them under cover to keep cold air away, fertilizing well, never letting the root system dry out and removing any late-season flowers that won’t have time to produce mature fruit. Removing healthy stems and foliage is not on the list.)

Do Remove Yellowing Leaves

No matter whether you grow tomatoes staked or in a cage, pruned or unpruned, it’s always wise to remove yellowing and dead leaves. They no longer contribute to the growth of the plant and can harbor diseases.


To Prune or Not to Prune?

Now that you know a little more about the situation, it’s up to you to decide whether you want to remove your tomato’s secondary stems so you can tie it to a stake or grow it inside a cage so you can forget about pruning entirely. Personally, I switched to tomato cages years ago and never prune healthy stems. Most years we end up with more tomatoes than we know what to do with… on only two plants!20170708A

 

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

31 comments on “The Truth About Tomato Suckers

  1. Linked to this post on our blog today: https://scmga.wordpress.com/2017/07/08/gardening-buffet/

  2. Grandma Kc

    This was really informative, thank you!

  3. Margaret Tabak

    Excellent article. I remove only the large leaves below the first producing stem. All others remain to protect fruit from sun, etc.

  4. Judy hatt

    How do you deal with tomatoe blit

  5. If growing indeterminate tomatoes in containers on a balcony, would there be an advantage to pruning the secondary stems to deliberately have a less vigorous plant and therefore require a less vigorous root system? I’m thinking of the pot size limitation. Obviously the bigger the better. But I imagine an un-pruned tomato would require a bigger pot than a pruned one. What do you think?

    • That would likely be the case. With less foliage, the plant would absorb much less energy and ought to there develop a less vigorous root system. This certainly happens with other plants that are pruned; I’ve just never heard of any testing this detail on tomatoes.

  6. Hello, I thought I was going crazy when I decided to stop taking the “suckers” I experimented with this one tomato plant I “neglected” (meaning, didn’t take the “suckers”) this plants production if crazy. I’m harvesting nearly 5lbs of cherry tomatoes a week!
    And the other one, 1lbs.
    The only thing I do sometimes is remove a few leaves from the middle for better area flow. This plant is between two trees only one string 3ft tall from one tree to the other. This plant is 4ft wide by 8ft.
    I’m giving all my neighbors tomatoes on a weekly basis.
    Occasionally I shake this plant a little for better pollination. I add lots of aged coffee grounds and grated to powder egg shell all around, I have lots of worms fertilizing this plant and all the others.

  7. Pingback: FYO: No, You Don’t Need to Remove Suckers from Tomato Plants – Laidback Gardener

  8. Pingback: Tomato Suckers – Grandma's Prairie Garden

  9. Spontaneous Gardener

    Nice to hear someone who gets that “suckers” are really simply branches. Nothing more. I’ve been doing a modified pruning technique where I keep the plant at one, or two main branches. Then, I let any further branches (suckers) grow on each of the main stems until they form a flower cluster. At that point I pinch the tip to stop it growing any longer. Each “sucker” has one flower cluster and a couple of leaves on it.

  10. Ian McGrath

    Very helpful advice. However, I have question that none of the sources I’ve looked at seems to answer: on indeterminate tomatoes, should I cut out side stems that are emerging from the base of the plant?

  11. Looks like all 3 pictures of the “pruned” vs “unpruned” are the exact same picture… Were they meant for comparison or simply place holder for volume?

    • They’re just to give an idea and not intended to show the real thing.

      • Mario Lafortune

        To give an idea of what a basket of tomatoes look like?
        I don’t understand, why show 3 baskets of tomatoes exactly the same while we are talking about comparison between a sucker crop vs non sucker crop… Not too convincing to me.

      • The photo is just an illustration. I have no side-by-side photo to show.

  12. I was also a bit puzzled at first, but then realised that this was simply a QUANTITATIVE comparison (twice as many).

    • 🤣 that picture is one of the reasons I am so excited to let a second main trunk to form. I didn’t realize they were the same photo haha 🤦🏻‍♂️

  13. This is the BEST article I’ve read on Tomato pruning. The second or even third stem can produce a significant amount of quality fruit. As long as the tomato can get access to nutrients (fertilizer). Many experts says that “suckers” don’t produce fruit but this is so untrue. Great article, I learnt a lot from it and am now confident to grow more tomatoes. I’ll see if I can tell the diff to see if it affects taste at all.

  14. I can agree with you that you can get larger non-prunned harvest if we talk about single standalone caged plant (with plenty space around it to grow secondary branches). In a tightly planted greenhouse with lots of free vertical space but scarce free horizontal space, i believe pruning out secondary branches to a single stem is the only way to keep foliage to a manageable density.

    • Well, I was really writing about raising tomatoes in a home garden, outdoors. Raising tomatoes in the tight confines of a greenhouse something quite different!

  15. D. Prashad

    I was pruning at first, but the plants (sweet 100 tomatoes) got so big that I couldn’t reach to prune the tops. It turned out that all the “suckers” at the tops gave flowers and bunches of tomatoes. No more pruning for me going forward.

  16. I would like to remove a portion of my tomato plant stem to root and grow fall tomatoes. Will I get a good crop like that?

    • Kate,
      You don’t need to remove a portion of the stem, removing a ‘sucker’ and planting it will work just as well. However, do you live in a very warm climate? Planting a tomato in the fall is too late in most parts of the US.

  17. I’m removing ‘suckers’ as i’m doing square foot gardening and planting the plants one foot apart, and it’s driving me NUTS! It seems so unnatural! I’m also removing the leaves from some ‘suckers’ and allowing the flowers to develop, which makes me worry about sun scald! What a mess! Next year i’ll plant them three feet apart, stake them on an eight foot high fence and just enjoy them! Thanks so much for the SENSIBLE information!
    elaine from NE Tennessee

  18. One reason I prune off the “suckers” on my tomatoes is to provide for better air flow since we live in humid Mississippi. Another reason is to encourage faster growth on the selected main stems that we want growing up our fence onto the over head trellis. Once the stems grow onto the overhead trellis system, I stop removing the “suckers,” and allow them to get to whatever length is most convenient to me harvesting them and beneficial for them to fruit. This process typically delays my harvest start until mid to late July, but we get harvests from then on until late September up to mid October.

    A third reason is that with a “trained” vine it is much easier to spot disease and pest outbreaks earlier. It’s also much easier to treat them because you can get to both sides of the leaves and all the stems. My chickens run underneath them, so any bugs that fall or we knock off are immediately dinner.

    A fourth reason is that the trellised vines overhead provide shade to the chickens.

    So it’s good to teach people WHY our ancestors began this practice so they can choose the appropriate method and plant variety for their garden! Good article! 😉

  19. I agree entirely with your viewpoint. I prune a little to facilitate harvesting and prevent leaves from touching the ground but that’s it.

Leave a Reply

Sign up for the Laidback Gardener blog and receive articles in your inbox every morning!

%d bloggers like this: