The Great Tomato Experiment: Does Pruning Effect Fruit Quality?

Which Hypothesis Do You Support?

  • Pruning bears better quality fruit!

    Votes: 0 0.0%
  • Pruning doesn't make a difference.

    Votes: 2 50.0%
  • Not pruning bears better quality fruit!

    Votes: 2 50.0%

  • Total voters
    4

hippiestink

Crowing
5 Years
May 9, 2015
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Bierbeek, Vlaams-Brabant, BE
Okay so for the BYC Gardening Thread I'm currently doing a Great Tomato Experiment. The experiment? Pruning vs. Non-Pruning.

The question is, does pruning tomatoes really significantly change the flavor and quality of the fruit? The current hypothesis of most experienced Garden Masters is that pruning bears better quality fruit while most gardeners in the thread don't notice a difference. So I'm going to find out once and for all which is better!


I am currently working with the following varieties. We live in the temperate Flanders region of Belgium, USDA growing zones 6-8; we get plenty of rainfall and relatively cool summers.
3 Indigo Rose (indeterminate)
3 Russian Black Sea Man (determinate)
3 Roma VF (determinate)

Of these, here is the list of pruned plants:
1 Indigo Rose
2 Russian BSMs
2 Roma VFs

Unpruned:
2 Indigo Roses
1 Russian BSM
1 Roma VF

They all are growing in the same zone, with the same amount of water and rainfall. All are watered every day to every other day. They get fed a homemade organic fertilizer once a week. The only changing variable is pruning. I pruned late after neglecting the plants through most of the season, as I didn't realize you could prune them, which meant that by the time I actually began, they were in bloom and beginning to fruit in some cases. The only thing I have done to the unpruned plants other than water and feeding is take off any yellow leaves or withered branches.

All are currently in flower or putting out first fruit. Three are fairly large, three are about medium, and three are kind of puny but have time to grow. This is being done in a rooftop garden in a large 1x1 meter tiered planter. I'm keeping relatively diligent watch and notes at this point, as I really haven't been this year and I want to do this experiment properly. Pruning took roughly three days to complete, so while we are technically on Day Four it is really more like Day One.

The unpruned IR plants have more immature fruit than all the BSM put together. The Romas are roughly in the middle with two half-developed tomatoes and a few small immature ones forming on the largest pruned plant. The BSM has only two half-grown fruits and one immature fruit on the pruned plants , with most blossoms still just flowers and not drying out yet.

The two unpruned BSM and Roma plants have only blossoms (and not many). All the IR plants are beginning to fruit, with the unpruned IR plants putting out more fruit than the pruned. I'll keep everyone updated daily on the experiment!
 
These are current photos of the flowers/fruits of each and every plant. They will be labeled for the purposes of this experiment.



The planter and plants involved in the experiment. (pardon my mess)



Small pruned Indigo Rose plant, already fruiting.



Small unpruned Russian Black Sea Man, fruiting.



Small unpruned Roma VF, flowering.



Medium unpruned IR, flowering.



Medium pruned RBSM, flowers and fruit 1



Medium pruned RBSM, flowers and fruit 2



Medium pruned Roma VF, flowering.



Large pruned RBSM, fruiting.



Large unpruned IR, fruiting.



Large pruned Roma VF, fruiting 1



Large pruned Roma VF, fruiting 2
 
Day two of experiment. Sky is very overcast and weather is calling for 95% chance of rain. We will see what this means for the experiment later.

The large pruned Roma VF has one branch that is browning, probably accidentally broke it or something when I was doing the pruning. None of the plants are showing shock, and several are fruiting at a steady rate.
 
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This is interesting. Some farms swear by it and others think its a terrible idea. I did it for a while and my tomatoes seemed to be producing less so I stopped.
 
Well the end of Day Two. It was actually sunny after 8:00 am and stayed clear and sunny until around 7:00 pm. Watered and fed as normal, got a little rain later in the day. No real change so far, though the large unpruned Indigo Rose is putting out more fruit. We got plenty of sun so the majority of the new fruit on the IR plants are turning black and the plants themselves are darkening. It's pretty cool, I've never seen tomatoes like this before and HAD to snap up seeds when i found them. They're just so cool!
 
Day Three and Four have been uneventful. The large unpruned IR is putting out a lot more fruit than the pruned one while the pruned RBSM and Roma bushes are putting out more fruit than the unpruned ones. Very interesting.
 
I think, like many garden articles have mentioned, it's not so much that pruning determines fruit production and quality. It's more determined by whether a plant is determinate or indeterminate. Many gardeners say it's indeterminates that need pruned or it's determinates and either way ONE type needs to be left alone and the other needs pruned.
 

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