How have you been watering? Are the plants in pots or in the ground?

IME it normally comes from inconsistent moisture uptake by the plant for what ever reason - lack of rain or watering, etc. Some varieties are more prone (sensitive) than others. What variety are these?

For reassurance you can always put "Blossom End Rot BER" in the search box (top of page) or Google and find other thoughts and ideas.

fwiw - adding calcium to the soil takes months to work, eggshells even longer.

The dwarfs are in 5-gal grow bags I have a drip irrigation system which I set to low trickle for 10 minutes every 6 hours. There hasn't been visible sign of stress on the leaves, and as I said, unless I completely missed it, the BER is a very recent development.

And be aware that although calcium deficiency is a cause of BER, it's calcium deficiency IN THE PLANT, and not necessarily calcium deficiency in the soil. High nitrogen fertilizers tend to make for the former without the latter. Fertilizers high in P tend to help. You need to research this a bit. Also, tomatoes planted in cold soil can end up having these for first fruits.

I've read all the discussions here about it, and had a fruit or two, but never this sudden and this many. I'm wondering if it's the variety. I've never grown a dwarf plant of any sort before, but my other New Big Dwarf right next to that one doesn't seem to have any issues (yet?). Or maybe it's to do with the fertilizer burn discussed in a previous thread.

Check every tomato, and toss any with BER. It usually clears up over time, and things should settle out soon.

To expand on Dan's point further <And be aware that although calcium deficiency is a cause of BER, it's calcium deficiency IN THE PLANT, and not necessarily calcium deficiency
in the soil.>

It is water that moves calcium thru the plant.

Keeping in mind that bearing tomatoes adds to the plants nutrient requirements kind of like when mom is bearing a child X20 or 30 fruit. You may find a difference in the number of fruit on the other plants.

No pics?

I tossed most of the BER fruit already. Kept one long enough to take a picture as you can see in the original post. Unfortunately, it looks like a few more are in the early stages of developing BER, but I kept them on the plant for now. My other New Big Dwarf plant does have fewer fruit and, as far as I can tell, no signs of BER. The other varieties I'm growing aren't showing any signs of BER.

If it were me - I would increase the watering time, esp. if you are in an area where a breeze wicks the water away. Plus, here in CT it is 102 right now, that can dry soil out quickly.

As mentioned that in time BER seems to decrease iIMO that is likely due to the fact that once noticed we pay more attention to the troubled plant and water on a more consistent schedule.

Also BER often strikes early in the plants development - maybe the above ground plant is growing quicker than the root system can handle. I usually find the plant grows out of it and BER disappears.

Tip: don't throw ber'd fruit. It happens in the fastest growing fruit. Removing a 'consumer' will just make growth stronger in another fruit and that will be affected in turn. Are the plants wilting at any point? Is the mix one of those 'much container optimized' (with bark fines and such that can't hold water more than a minute)?

I assume you know that by the time the BER becomes visible to the human eye the actual damage, if we want to call it that, was done way back? It just wasn't visible. So it isn't a sudden appearance per se.

And of course, it is far more common when one uses small containers.

Dave

If that's the case, why am I noticing it on tomatoes of various sizes at the same time? Of course it could be me, and I wasn't looking as closely before.

As far as others posters having mentioned about typical calcium sources being too slow to make an immediate difference for BER problems I do something that may be frowned upon. To get my plants off to a fast start I'll sprinkle a teaspoon of Calcium Chloride around each one, it's water soluble and dissolves quickly and is available to the plants immediately unlike eggshells, lime, or typical Ca sources.

CaCl is the enivro friendly ice melting salt which is replacing rock salt for winter use. As with KCl in fertilizers you don't want to overdo the Cl addition to the soil so it's best to use it in moderation. I find that 1 teaspoon sprinkled around the plant gets it off to a good start and allows the roots the time to grow deeper and ward off BER for the later tomatoes as is the usual case for maturing plants. Might try it on one plant to see if it helps.. My plants are in-ground, not potted up in various forms of containment.

eta : the timing of the CaCl would be as the plants first bloom for new plants.

"If that's the case, why am I noticing it on tomatoes of various sizes at
the same time? Of course it could be me, and I wasn't looking as
closely before."

There is no direct correlation between BER development and fruit size. It can happen at most any point during fruit development although it is most commonly seen in early spring-set fruit. And if the cause of the damage - inconsistent moisture and uneven Ca distribution - happened over a period of time then one would expect to see the visible symptoms show up in various sizes of fruit.

Dave

Been growing tomatoes for 50 years and I have never had ber this bad, usually it clears up but not this year.

Prob going thru a drought?

I had blossom end rot, so I started to make watering more consistent. That didn't work, so i used an eggshell vinegar mixture diluted in water, and that seemed to clear up the issue for me.

I think watering problems are in fact what was wrong. My drip irrigation timer was mis-configured. After catching that BER mostly cleared up, though it's still non-zero in all my plants (except the Sun Sugars. Do cherries get BER?), even the ones in my raised bed (last year the number was essentially zero).

BER is more common in larger tomatoes, such as beefsteaks. It happens when there is not enough calcium in the cells and the bottom cells collapse under the weight of the tomato. Tiny tomatoes almost never get BER. BER tomatoes and peppers