does humidity affect blossoms drying up and dropping off? Help

[Garden78]

hi. I am growing better boy tomatoes and I am seeing alot of my blossoms drying up and dropping off. The weather here in fredericksburg, va, has been fluctuating between high humidity and medium humidity. I have been keeping my plants watered since they dry out fast. Does humidity have any affect on whether blooms open up and set fruit versus drying up and dropping off? Should I add fertilizer to help correct this problem? Is this a deficiency of some sort? any help would be greatly appreciated.
Conor W.

[KarenO]

Humidity can cause pollen to clump but more often the cause of blossom drop is a high temperature. Anything 85 degrees and over will certainly affect pollination and blossoms will drop off. Helping things along by shaking the trusses can sometimes help a few to set
Karen

[Worth1]

Heat is more of a factor as was stated above.
I have had bloom set with temps in the 70's with 90% humidity.
But as the temp goes up the humidity will start to play a role.
It is a fine balancing act between the two with only a few degrees difference.
Right now my temp is 94 and the humidity is 51.
My cherries are setting fruit because the nights are cooling off to about 73.
This year I have the worst looking plants with the best tasting tomatoes I have ever had.
Total neglect.

Worth

[AKmark]

In a greenhouse humidity is the sworn enemy, it will cause pollination problems and the flowers will die, then if you don't clean the flowers up, you invite mold issues, and rot, that eats into your plants.

[Garden78]

Is there any type of spray that you can buy at a local nursery or garden center that will help with blossom set and prevent them from drying up before they bloom and falling off?
Conor

[Worth1]

Originally Posted by Garden78

Is there any type of spray that you can buy at a local nursery or garden center that will help with blossom set and prevent them from drying up before they bloom and falling off?
Conor

One great big ((NO)) they will tell you this but it isn't what it is for, it is a spray used to help blooms set fruit in cooler weather.
I dont have a problem with cooler weather where I am.
It will not help in hot humid weather.

Here is what Carolyn137 has to say about it on another forum.
I hope she doesn't mind me posting it here.
It was just too much for me to explain and is very useful.
"
That product was devised to be used in areas where the Springs are cool and fruit set is a problem. It was not devised, as the FAQ says, for helping fruit set when temps are too high.
So in places like the PNW it can help, and other similar areas.
But, it also induces what's known as parthenocarpy which means that fruit development takes place in the absence of pollenization and that can lead to several problems.
First, few to no seeds since the ovules in the tomato ovary are not fertilized. Second, fruits can be malformed and mealy. Aside from the few seeds, the other two problems don't always happen.
Dr. Jim Baggett, at Oregon State U has bred several parthenocarpic varieties and I think the best known one is Oregon Spring.
Blossom Drop is, as you pointed out, often caused by temps being too high, either in the daytime or at night. It can also be caused by high sustained humidity which can lead to clumped pollen which is much less effective.
YOu don't indicate where you're located so I don't know what your local conditions are.
Once the temps drop a bit that will help.
In the meantime if you want to shake the plants a couple of times a day that might help as well, or may not if the pollen is not viable.
The normal blossom cycle is about three weeks so if the temps do drop a bit it's very possible that new blossoms will do better.
Hope that helps.
Carolyn"


Worth

[carolyn137]

Of course I don't mind that you posted it here. I don't know where I posted it and have done so many times here and elsewhere.

And it's still true.

Carolyn

[Garden78]

thanks for your input carolyn and worth. I live in fredericksburg,va, which is kind of in the northern part of the state. There have been a few blooms starting to appear and fruit is starting to grow. I just hope it continues to happen and I hope it happens on the one tomatoe plant that I grew from seed.
Conor