The Tomato Sucker Experiment

Gretchen's results: tomato harvest - the 5th of October, 2013 - Baltimore MD

Gretchen's results: tomato harvest - the 5th of October, 2013 - Baltimore MD

It all started in January, 2012, when I redid my my page on growing tomatoes, and I got a comment:

Great article, but I didn't see removing sucker leaves in it.

When you look along the main stem of the tomato plant you will see little leaves growing in the crotches of the off shoot branches. These are known as the sucker leaves. They serve no real purpose to the plant, other than suck up nutrients that the rest of the plant can use for setting the fruit. By pinching off these little suckers, you are helping the plant to grow bigger and better and more Tomatoes. You only want to remove them from the main stem. All other leaves are needed to absorb the sunlight needed by the plant.


To be honest, I'm a little hazy on the "good leaf, bad leaf" thing. ;)

So I googled "tomato sucker leaves", and found ten articles saying ten different things: Prune all suckers! Only prune indeterminate tomato plants! Pruning gives your plant more sugar because the suckers steal it for themselves! The sucker leaves make more sugar and should be left on!

Ooo ... a controversy!

I've always grown tomatoes in extremely hot and dry areas of the country, and in my opinion, leaves are there to shade the tomatoes! If you're one of those people lucky enough to have tomato plants that grow so wild as to actually need pruning, prune them, but I don't bother, and my tomatoes seem to turn out just fine!

But I'm the last person to pretend that I know everything, so I asked people to write in with their thoughts ...

Kat writes:

Here in zone 10b, Santa Monica Calif. southwest US I have a community plot 2 blocks from the beach and have a heck of a time growing regular tomatoes, since we have typical "June Gloom' where its foggy and cool. This year I bought, in late summer, a tomato plant that develops in winter, (Sorry, lost label name) and I had golf-ball size tomatoes all winter and 10 on New's Year! The plant just now looks bad but the tomato are still hanging on there ripening in our winter sun. (Today Feb 1st is about 70F and sunny, which is better than in June). Its my professional opinion that in Southern Calif. you don't need to prune tomatoes or take off the sucker leaves ... the plant needs as many leaves as possible to produce enough energy to produce lots of tomatoes, and inland from the beach they need the shade of their own leaves or the stem will burn.

Soil amendment and food complete food is the key to healthy plants for a good production of most all plants. Pruning as necessary to keep the plant in reasonable bounds and give air circulation if humidity is a problem.


Susan writes:

I have had great luck here in Denver central US pruning the tomato suckers. I didn't always do it - but the last couple of years that I got pretty hard core about it my tomato plants were fantastic! They grow taller and produce so much more fruit. My heirloom tomatos were over six feet tall (secured to bamboo poles) last year using pruning, a drip system, and only my own compost.

Karen from BC, Canada writes:

My father-in-law swears by pruning off the tomato suckers, I more or less just swear at it! However, he is diligent and usually does get a better crop than I do so I guess it does work if you are diligent.

Jan writes:

This really is a controversial. I go both ways with this.

Last year, I didn't prune very many of the suckers and my tomatoes were so dense you couldn't find the fruit. I thought I should of been pruning more of the suckers. But as temperatures rose above 100 for days on end - I thought they needed that extra shade during the day.

Not sure if you'd get more fruit or end up burning up the plant.


Gretchen writes:

I grew up not plucking them, but then I met my husband's mom, a biologist, and she said I had to pluck them off. Since then I have because her reasoning made sense, but I never conducted my own research. Maybe it's time!

I think we need an experiment. This is what I propose:

Everyone who wants to grow tomatoes, prune the suckers off half your tomato plants and keep the other half on. Make sure the plants are growing in the same conditions and are equally healthy. Then let's take photos and see how they do.


Did you do the experiment? Tell us what you discovered! Send any photos to patty @ edible-landscape-design . com (remove the spaces) and I'll put them up at the top!

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Mar 15, 2015
No longer a sucker plucker!
by: Gretchen

[I did not prune out suckers this year] and eventually got a bumper crop of tomatoes on 3 different plants: 1 Amish paste tomato, 1 purple Cherokee-type heirloom, and 1 yellow heirloom. The plants were rather lush, but I got more tomatoes this year than the past 2 growing on the same plot.

I don't have good long view photos of my garden showing how big the plants got, but I've attached a photo of the harvest I got on October 5, which shows some of each kind. I picked all the tomatoes off the vines this past weekend and chopped them down for the season. I got upwards of 10 pounds of green Amish paste tomatoes and a big bowlful each of the purple Cherokees and yellow heirlooms. We have plenty of tomatoes for just 2 people!

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