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.
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!
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.
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?
- 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
- 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.
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?