Tomato Suckers: To Prune or Not To Prune?

If you’re looking for a good garden debate, look no further than the question of pruning tomato plants. You’ll find no shortage of compelling arguments and strong opinions in both camps.  Some gardeners swear by it, others never do it, and both get tomatoes in the end, so how do you decide if you should prune your tomato plants or not?

The good news is that pruning is neither necessary nor harmful (assuming it is done correctly, of course), so you can do it–or not–and still have a successful garden. More important than if you are on Team Prune or Team Sucker, is figuring out what works best for you and your garden.

Tomato Suckers: To Prune or Not To Prune?

When gardeners talk about pruning tomatoes, they’re generally talking about removing all but perhaps a small number of the “suckers” that grow where the leaves branch off of the main stem (we’ll get to low-hanging leaves and leaves that show signs of disease in a minute).    These little shoots will grow leaves, suckers, and tomatoes of their own if they are allowed to continue growing.  This growth pattern is what gives tomatoes their tendency to grow both up and out and eventually into a full-fledged tomato jungle.

The pruning process is pretty straight forward: if the suckers are still small and flexible, they usually just snap off cleanly with a firm grip at the base; if they are not easily snapped off, sometimes a sharp knife or pair of garden shears is necessary to get the job done.  Just be sure you are not pruning out the main growth point at the top of the plant!

Tomato Suckers: To Prune or Not To Prune?

One of the most common things you’ll hear on the topic is that pruning will result in better tomato production, but there are studies (like this one) that suggests that all things being equal, it may not really make a difference in overall production.  Pruning tomatoes can produce larger, earlier fruits, because energy that would otherwise be spent growing foliage is redirected into growing and ripening the tomatoes.  However, tomato plants that have not been pruned can produce a larger number of tomatoes because there are more stems producing fruit and more leaves producing energy.  In the end, a smaller number of larger tomatoes adds up to be about the same as a larger number of smaller tomatoes.

Of course in the garden, all things are rarely equal, and there are differences in growing conditions, available space, and the prevalence of pests and disease, and the issue suddenly becomes much more nuanced and pruning or not pruning can have a much bigger impact.  There are short season gardeners that rely on pruning to ensure their tomatoes ripen by the end of the season and gardeners in locations that rely on un-pruned tomato foliage to protect their harvest from sun scald. Carefully pruned tomatoes make it easier to find and destroy tomato hornworms quickly.  Determinate varieties only grow to a certain size and set a certain amount of fruit, so pruning is counter productive.  Gardeners with big sturdy cages and lots of space might not have to worry about pruning, but small space gardeners who use stakes or twine trellises to fit it all in do.

Tomato Suckers: To Prune or Not To Prune?

As a gardener you really have to get to know your garden and figure out what works best for you and your goals.  Are you concerned with managing Early Blight?  Do you want to do things as simply and naturally as possible?  Do you just really like the way a perfectly trellised row of tomatoes looks?

Here are some of the more common reasons why gardeners prune tomato suckers:

  • To increase air flow + reduce risks for fungus/disease
  • To make more efficient use of space
  • To make certain types of staking and trellising easier
  • It can improve production (larger, earlier tomatoes)
  • To expedite ripening by forcing plant to direct energy to fruit instead of new growth
  • To cull flowers + fruit that will not mature by the end of the season
  • To more easily find + remove destructive pests
  • To make harvesting easier
..and a number of reasons why gardeners do not prune tomato suckers: 

  • If you are growing determinate varieties
  • To allow the plant to grow naturally
  • To allow more leaves to photosynthesize, producing more energy for the plant
  • To avoid introducing disease through pruning wounds
  • If you are using cages to support your tomato plants
  • To provide protection from sun scald
  • It can improve production (more tomatoes per plant)
  • To keep as much healthy foliage as possible in the event diseased foliage needs to be removed

Of course the important exceptions that even avid no-pruners should make are removing the bottom leaves from the plant that come in close contact with the ground (to prevent soil-borne disease from splashing up onto the leaves) and any leaves that show signs of disease (to prevent or at least slow the further spread of disease), as this is just good practice.

Tomato Suckers: To Prune or Not To Prune?

My personal preference is to just let my tomatoes grow without pruning the suckers.  I find it to be less fussy and In my current set up, I’ve encountered fewer problems with keeping my plants upright with the use of heavy duty cages than trying to tie everything up to a single stake.   I also think it’s best to let the plant produce as much energy as possible, as the whole point of growing tomatoes is to get tomatoes, so in my mind, the more the better (and my own anecdotal experience is that size has a lot more to do with variety selection than anything else).  Why mess with what Mama Nature has perfected? The other big reason I do not prune, is that Early Blight is hard to avoid in our humid summers, even with the best preventative efforts.  There will come a point in the next couple of months where I’ll have to start pruning out blighted foliage, so I want to keep as much healthy foliage to maintain production and protect the tomatoes as possible.

If I had more time, or a different set up, pruning might make more sense for me, but this approach works really well for me right now.  It’s manageable and it leaves time for me to enjoy my time in the garden, which is what we are all going for, right?

I’d love to hear from you: What works best for you and your garden?

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7 Responses to Tomato Suckers: To Prune or Not To Prune?

  1. I did not prune my tomatoes (much) this year, except for the bottom stems and leaves. I now have a totally unmanageable and crazy tomato patch, but I think it’s less due to not pruning and more due to not spacing the plants more. They are way too close together. I don’t know how I’ll even get to the tomatoes when they ripen and tomato hornworms will peacefully thrive in there because I would NEVER see them! That said, the plants are loaded with unripe tomatoes now, and I think I’ll have a decent harvest.

    • Maria says:

      I can so relate to that feeling of not being sure how I’ll get to certain tomatoes in the depths of the jungle! Good thing ripe tomatoes are excellent motivation to make it happen! :)

  2. Gail says:

    Last year was the first year that I did any pruning to my tomatoes though I did not do it until the 2nd last week of August. We have a short growing season and can have first frost by Sept. 1st so as we got to the end of the growing season, I removed all new growth. I figured that any thing blooming this late in the season was not going to set and mature enough to ripen in the garage so I would let the plant put all of its efforts into the fruit that had already set.

    • Maria says:

      Several years ago I did the same thing (removing the new growth that wouldn’t have made it anyway) when it was getting later in the season and nothing was ripening yet. It really did make a difference!

  3. Angie says:

    I’m the same as Brande – I did not prune mine, and mine were spaced a little closely (raised garden beds, square-foot gardening), and alas they are a tomato *jungle* But there are plenty of tomatoes and plenty of blossoms. :)

    • Maria says:

      I grow my tomatoes in raised beds as well, and I have to admit that I’m kind of partial to the jungle look :) I love how lush and productive it looks, particularly when they start loading up on tomatoes and blossoms!

  4. Jes says:

    I start out by pruning and then at some point the plant inevitably gets too big too quickly and I can’t keep up. Some of my 20 or so (yeah, I got a little out of control this year)tomato plants are big and bushy and others are spindly and weak. I had a problem early in the season with black spot that weren’t from sun scald (I’m in SF, it’s sunny in my neighborhood but I have them shaded by our huge plum tree). So I had to toss a lot of my bigger plants. I’ve been plagued by more aphids this year than usual. But neem oil and insecticidal soap have helped with that.

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