Tomato blossom drop, usual suspects ruled out
So my 'Celebrity' and 'Supersweet 100' tom's are looking great. Beautiful foliage and lots of blossoms on both varieties. Because we have such cruddy soil and thick unmanageable caliche that goes several feet deep (had to literally rent a jackhammer in order to install a fence, before we gave up on that)-- the tom's are in huge pots. I've grown them this way for years with great success.
However, this year the blossoms are opening up, staying on the plant for several days, then are falling off at the abscission joint. The blossoms go through a wither, as if they had been pollinated, but then just drop. I opened a few dropped flowers and there is no sign that they even got pollinated. The ovarian "remnant" is small and "atrophied" for lack of a better term, like the flower was an old maid (my term for an unfertilized bloom).
Here's some more details:
We haven't had any excessively cool weather, nor have we had many days over 90... I think we've had one 90-degree day, and nights have been mild and cool but not chilly-- 60's for lows most nights, highs in the low to mid 80's on average with some days in the upper 80's. Rain has been lighter than usual, but not droughtish and I water only if the soil is dry at a depth of 3 to 4 inches.
Fertilizing-- I made sure to include a source of phosphorus at planting, and plenty of it. Calcium is abundant in our soil here (caliche is lime, a form of calcium carbonate) and I have plenty of good amended soil as I have used in the past.
Bugs and pests-- except for a few tiny young hornworms which I promptly addressed (the buggers were less than 1/4" long when I found them-- very young indeed), I have no bug or blight issues.
Environmental-- plenty of sun, about 8 hours a day with a bit of sun screening during the hottest part of the day. The sun screen still allows light through, but not as intensely blazing-hot as full-on sun. Plenty of air movement, too. I see the plants and flower trusses shimmying in the breeze, so the flowers do get vibrated, and I also give gentle love-pats once a day if it's calm out. Temps seem ideal for tomatoes, not too hot or too cool. The plants were transplants, and got planted the first week of April. Yes, it is a bit later than I usually set them out but we had almost 6" of snow on March 21 (an extreme rarity in Dallas) so I wanted to wait to be sure we were really done with winter before setting them in the dirt.
So, why would the blossoms drop despite "good conditions", sufficient (I think) phosphorus and calcium, ample air movement, being evenly moist but not over-wet, sufficient light, a lack of pests/disease and everything else SEEMING okay?
Oh-- my peppers are doing the same thing: big blossoms that just fall, but in that case the ovary stays on the plant but fails to develop and then also falls... but that's a Q for the pepper folks... I digress, but perhaps there's a common problem?
Thanks for your help.