What happened here? IN THIS 1OO degree weather I have that happen ,believing it to be plant stress. Plants are trying to conserve their energy. One or two out the spire columns that hang are dropping green stem and all at the flower,the remainder of the spire grows and develops tomatoes.Tomato plants don't really like all day sun in 90 to 100 degree weather.As to that particular; I don't care what the instructions say.Experience says and agrees with me!!
Paul, I see no message in your first post, just saying you edited it, so I don't know how to answer, really, so I will anyway. LOL
THe major cause of blossom drop occurs where there's high sustained heat over about 85 to 90 F, it depends on the variety, and what happens is that the pollen itself is denatured, meaning it's destroyed. The normal blossom cycle is about three weeks and it's random, so as soon as temps return to normal blossom drop usually stops.
THe high temp problem is made worse if a person is growing tomatoes where there is or has been high sustained humidity, b'c that causes the pollen to clump, making it much less effective, thus leading to blossom drop as well.