These aren’t the kinds of smiles you want to see radiating from any of the plants on deck.
POD’s pretty sure this is a nasty case of blossom end rot. Which, essentially, is a calcium deficiency. The good news? It’s not contagious. The bad news, there’s a chance there’s not much to be done at this point.
So, in the hopes of avoiding this next year, what caused this nastiness? Well, external stress like lack of water and excessive heat could be a factor. (It was pretty brutal a couple of weeks ago and with a vacation nibbling into obsessive-compulsive gardening, the plants were only watered once a day, rather than twice a day). Honestly, that’s what we’re really, really hoping for. That can be immediately addressed.
Also worth noting, this is the only tomato planted in Miracle Gro Organic soil (the Isis Candy, Black Cherry, and Gold Nugget were planted in either Organic Mechanic or Coast of Maine — both of which seemed like much richer, less mulchy soil blends). And, because this fella’ was a rather late and unexpected arrival, I just can’t say for certain whether or not it received the crumbled egg shells its compatriots enjoyed. Next year, the soil can be gussied up with a shot of bone meal, too. And yes, maybe it’s time to invest in that Ph kit to make sure the soil’s around 6.0-6.5.

Its slightly curled leaves add further evidence to the diagnosis. While adding milk to the soil and spraying with the powdery mildew mixture (which contains milk) is tempting, it probably won’t do much as calcium isn’t immediately absorbed. Which isn’t to say both “remedies” haven’t already been applied. It’s worth a shot.