Most likely cause of no blooms is excess nitrogen - causes bushy leafy growth but few to no blooms.

Most likely cause of no fruit set when blooms are present is heat and humidity as with the condition called Blossom Drop.

And there is always the issue of early, mid, or late season variety.

Dave

Here is a link that might be useful: Blossom Drop FAQ

Thank you Dave. Like I said, other varieties with same growing conditions are fruiting fine. No excess nitrogen/green. there are flowers. Flowers just dry up/die. I just checked the maturity numbers, 73 days for Marglobe, 78 for Dr. Wych's. The plants look fine, no disease.

Few of my tomato plants are currently setting fruit in the high heat SoCal is experiencing. I would guess late March is too late to be sowing seed in Dallas. In my climate, ideally I set out plants mid to late March. A lot of TX growers that post elsewhere are starting their seed in January, some even sooner. They put them out early with protection to get fruit set before the high heat sets in.

Flowers just dry up/die.

Ok then are these particular plants located where they are more exposed than the others to hot dry winds? Low lying area with different drainage? Less sun? Any signs of thrips or other pest? Or anything else that would define a different growing condition for them?

I have only grown Dr. Wyche a couple of times but my notes don't show any particular problems with it. Grown Marglobe many times but only negative note I have on it is "good production in number of fruit but fruit consistently crack both in ground and in container".

Dave

It is due to the heat, and high humidity. Keep the plants as healthy as you can, and watered. When it cools off in September you will see it start to set fruit.

I am 2 hours south of you, and the only plants I have setting fruit are cherry varieties. We had a brief cooler spell, and a couple of plants set a hand full of fruit. The trade off is they stunt as soon as the heat kicks back up. I have beef steaks that ripened slightly larger than golf ball sized fruit.

Same here as centex on my beefsteak. With heat-index adjusted temperatures max below 95 F and nights minimum temp in the low to mid 70's F under high humidity conditions I had about 30% setting. Then we had about 10 days where the heat index adjusted temps went to about 110 F max. All blooms fell off dried.

Now we are off the heat wave to the first temperatures and I'm seeing a few setting again, as well as picking what I had counting on being juicy huge tomatoes but ended up as stunted, ugly beefsteak miniatures in the 1.5 to 3 ounce range, instead of 6-12 ounce "pretty" shaped range.

The first 3 tomatoes after the heat wave that managed to set are already bigger than 3 ounces and no longer have anomalous random shapes, but look like your typical beefsteak again.

Probably the varieties that aren't working are more sensitive to heat, or something like Dave suggested.

If you have really low humidity, the same can happen, because the pollen loses it's stickiness, from what I've read. Not a problem in FL but probably out West it is ...

Centexan254: thank you. That sounds like the right reason. My other tomatoes are also smaller than they should be. I have also been skimping on water.

Another question: should I trim/prune the plants (the branches that don't have any fruit on them now) in preparation for them to start fruiting again when it cools down some or just leave them as is, most of them at 5-6 feet high. If the answer is yes, can someone give me a little more detail on which branches to trim and where (if that matters)? Thanks.

If the branches are healthy then I would advise to leave them as they are. More branches will give more fruit when it does cool off. If they are in cages then they will drape back down the sides.

The only pruning I do is taking off the dead, or dying branches.

This post was edited by centexan254 on Tue, Aug 5, 14 at 18:50