what night time temps will shut off tomato blossoming?

[mopinko]

finally starting to get tomatoes. what a shitty season. such a cold wet spring.
as usual, i want the fall to stay away. with the talk of el nino, i was hoping i would catch a break. but they are predicting at least 3 nights next week w lows in the 50's. i am in a little bit of a microclimate here, because of the lake, and also because my hugelpiles create a little warmth. might save me this time.

but, what is the trigger? when should i start to cry?

[Paper Roses]

1. Terrible growing season here, great for weeds and not much else.

Will not get back the price of seeds, fertilizer, flats and labor. Phooey! Wondering if it was worth it this strange growing season.
Zone 6. Either no sun or scorching heat. Anemic veggies, hearty weeds.

[dixiegrrrrl]

2. Maybe this will help....I googled for you.

Blossom drop will occur in the spring if daytime temperatures are warm but night temps drop below 55 degrees F. (13 C.). In the summer when temperatures soar over 90 degrees F. (32 C.) with nights over 76 degrees F. (24 C.), again, the tomato plant will suffer damage to immature fruit or loss of flowers.

Additionally, when nights become too warm, the pollen grains of the tomato flower begin to burst, thwarting pollination, hence no fruit set. This is doubly true when the air is saturated with relative humidity.


The growing temp for tomato seedlings should be maintained at constant temps of between 58-60 degrees F. (14-16 C.), whether starting in the greenhouse or indoors, and then not transplanted until the last frost has passed.

down here in SW Alal we have opposite problem.....no tomatoes when temps get above 70 at night and 80 daytime.
So I cut all my plants back to a few inches of stalk, they grown again during hot weather and set again in fall.

[bvar22]

4. Duh!

I feel like an idiot.
We will be trying your cut back technique when the temps go past 95 and see what happens in the Fall.
Thanks for this tidbit.

I told my wife about your technique,
and she said, "Why didn't we think of that!"

[dixiegrrrrl]

5. Ha...I did not think of that until about 5 years ago!

Now, to be fair, I spent half my life trying to garden in the PNW where getting tomatoes to produce is a huge effort.
The cut back technique works real well down here in the South where there is a 8 month growing season.

The trick to cutting them back is to leave 10 inches or so of stem AND some leaf buds/branches still growing.
think of it as just whacking the top 2/3 of the plant down/off.
Keep them watered and when the right temp combo shows up again, give them a shot of fertilizer and they should be good to go.

This works for both determinate and non-determinate varieties, btw.

[NRaleighLiberal]

3. they keep blossoming - it's about setting fruit, as Dixie's link stated.

Other issue - lower sun angles, less photosynthesis, less flavor development - slower ripening. It seems to take about 3 weeks from fruit set to ripe tomatoes in the dead of summer, so that even slows. Calculate back from your frost date to see if it is worth it. You can also top prune the plants so more energy goes into developing the set fruit, less into further plant growth above.