I assume it's to break loose and stir up the pollen to get it to the stigma of the flower for pollination. Bumblebees use a similar trick where they grasp the tomato blossom and "buzz" the pollen loose by beating their wings. That's why bumblebees are excellent for your tomato patch.

Thanks tcstoehr for the reply. Is this really necessary? I admit I'm a little new but what happens if you don't? Less yeild?

Val

Lower yield. Some varieties of tomato just don't set as many fruit without a little agitation.

Each tomato flower is self-pollinating so agitation helps when few bees are around. Someone mentioned a while back that they use an old electric toothbrush placed against the flower cluster stem to do the "work".

> what happens if you don't? Less yeild?

Who knows? Probably makes no difference. But that was sort of the point, it's just one of those goofy things gardeners do.

I honestly do think that it does make a difference. I have been shaking cages and thumping vines for a number of years and almost always have a very good fruit set. I noticed a little tomato on an Aunt Gerties Gold this morning that I had about given up on, probably because I did not give up on shaing the cage it is in and the plant some. We have had nearly continous rain for the past week to 10 days and high humidity which is not conducive to setting tomatoes.
That is my .02
Bill P.

I have gardened for a long long time and I had never heard of thumping the flower until this year...and I too, was wondering why..

I've been gardening since I was a kid - I'm 43 now and never heard of thumping a tomato flower until I read this thread. Weird.

This is my first time gardening this year, but most of the gardeners i know grow tomatoes have never mentioned this. I am growing tomatoes also and every blossom has turned fruit.

Don't know if turned fruit is a term. I hear my neighbor say it sometimes.

Well, I'm kind of new at vegetable gardening so I "know" I don't know it all....so I asked my grandma (91 years young) and she looked at me like I was crazy :-)

It would be fun to take a two tomato plants (same species of course) and thump one but not the other to see if they do anything different. The problem would be "coincidence" and how to account for it. Not sure you could. Oh well...it was an informative discussion anyway.

Val

Coincidence is easily accounted for by running a statistically significant number of tests. Thump all of the flowers on every other tomato plant (assuming you have at least a couple dozen plants) and check out plant yields. If you don't have that many plants, you could thump every other flower on every plant and mark those flowers off with something that won't affect development to indicate which ones you thumped.

If anyone does this, I'll run the numbers to figure out the statistical significance of the results.

The thumping wasn't doing me any good with my Marianna's Peace, last month. I got desperate and went to the next step, actively mashing plucked flowers against the stigmas. Now I seem to have plenty of fruit set!

Marianna's Peace may be a more difficult case than other tomatoes because it has an exerted stigma.

I thump everything, even my blackberries and raspberries. It's good for their character. My Dad used to thump me and I turned out okay.

How do you thump the flower? Do you touch it and squeeze it ?

My tomato plants are staked using iron rebar, just rattling the rebar between my thumb and fore/index finger gives the whole plant a good steady vibration.

I use a battery operated tooth brush. You can actually see the pollen released from the flower if you look closely at the correct angle when using the tooth brush.