A Gardeners Forum Forums General Discussion The Food Garden Forum The Tomato Forum Too hot for blooms to set?

My tomatoes are in topsy turvy planters. They are doing fine, have produced tomatoes and even though they continue to bloom, they are not getting many new fruit.My patio gets so hot you cannot walk barefooted on it, it has been above 95 here for the last 3 weeks at least. Will this prevent my plants from producing, i added foil around my planter to keep it from getting so hot, i put up my umbrella to shade them in the late afternoon and the cups in the top allow for slower watering so it has time to absorb water and fertilizer.They were also a lot bigger but i cut them back as they were dragging the ground and getting fried. should i have not done that maybe tried to tie them up instead?

http://www.flickr.com/photos/40139263@N06/3687267941/

I know down here in TX my tomato plants don't set blooms when it gets too hot. and it got hot earlier then then norm this year,, I only got 4 tomatoes to eat before it got in the upper 90's and triple digits

I wonder if that is why my tomatoes slowed down, diane? it is the heat that makes them stop putting out fruit? I was getting on average of 2 tomatoes a day up until 2 weeks ago. and now not a thing! even the small green ones don't want to grow bigger or turn red..... hmmm!

rockie, I've grown tomatoes for years and when the heat gets up there the bottom leaves always look pitiful. I don't worry about it too much as long as are still producing. I don't prune. I tie up once, once they get big and need support, but then if they are still falling over I don't do anymore with them. I let them go wild.

I'm sure you didn't do any damage by cutting. as long as the cuts were nice and clean.

If I'm not mistaken-- and if I am,I know I will be corrected-- temperature IS a significant factor in the tomato life cycle. Reproductive organs-- flowers-- will not be produced if nighttime temps are consistently below 50 degrees, and there is an upper limit too (don't know what it is, but I'm guessing, based on experience, about 75-80). Again, I could be wrong, but as I recall it's nighttime temps that are critical for flower/fruit set.

I'd just ride the tide. As Cricket says, let them "go wild" and produce a lot of vegetative growth. When things cool down a bit, all of those vines will want to reproduce = make tomatoes!

I kept a daily record of my harvest last year, and I'm looking at the graph (I'm such a geek) right now. I peaked mid-August, but had just as big a peak early October. I'm in zone 6, and had a very late start. So offsetting for zone differences, I'd say don't worry!

Cricket not only did mine stop setting flowers it also started to die back, in the triple digits,
I cut off all the dead,, set it in the shade it only gets dappled afternoon sun and it has new leaves coming out,, I've not seen that before, so I'm going to baby it maybe I'll have tomatoes in the fall if I don't let it burn up! ( it's a potted beef steak)

Heat and humidity is a big issue. Humidity can cause clumping of pollen. Also some varieties are more sensitive to heat when it comes to setting. The general rule is temps need to be 90 or lower in the day and mid 60's or lower at night. With those temps most will set. I get some set on some varieties here in the heat. The one positive I have is low humidity usually. Also if you shake of brush the plants that helps. I try to twice a day. I usually do mine in the morning and evening. If the plants are wet of a morning from a dew ect don't touch them. This is all just my opinion. Jay

Yes, rule of thumb is 90 is the upper limit for fruit to set, but that's a generalization. Some plants, even of the same variety, will continue to set at least some fruit beyond that, and some varieties are less affected. Some vareities have been bred to set in high tmeps. As Jay mentioned, though, humidity is a big factor too.
Take a pencil, a chopstick, or any other thin tool and just tap each blossom several times once or twice a day and you definitely will get at least a few more fruit than otherwise.
I believe the residual heat rising from the ground at night has a lot to do with impeding fruit set, because I've observed that 90 and 100 degree daytime temps early in the season allows more fruit set than later in the season, and it's my guess that this is because the ground is holding and radiating heat more as the summer goes by.

So now we're talking to our plants AND taping the blossoms with a chopstick???? My husband already thinks I'm nuts.

You think that's bad, I heard of one guy that rigged up an electric toothbrush 'vibrator' to shake the blossoms, and another guy uses the buzzer out of a cellphone to do the same!

do you have their numbers? I'll ask for the plans. :wink:

You agree with me!

(actually, I STOLE the idea from you! :wink:)

Yes!

Night time temperature above 75 degrees F will burn food reserve produced by the tomato plant during the day and abort the flowers.

I believe the residual heat rising from the ground at night has a lot to do with impeding fruit set, because I've observed that 90 and 100 degree daytime temps early in the season allows more fruit set than later in the season, and it's my guess that this is because the ground is holding and radiating heat more as the summer goes by.
I agree with both of you. And that is another reason I think mulch really is important. Where I mulch heavily I have better fruit set. I have seen this several times. It is my opinion that the mulch keeps the soil some cooler and also radiates back less heat than bare ground. You also use less water. Jay