It is called BER (blossom end rot) and is very common. There is a great detailed FAQ here on it (over on the Growing Tomatoes forum) and lots of info on the web once you know the search term.

Dave

Here is a link that might be useful: BER FAQ and discussions

Thanks for the starting point! :)

Ugh. I must say, after spending hours reading about and caring for my garden, how discouraging this is! :-( I feel I watered correctly, between 1-1.5 inches per week w/ a soaker hose. Maybe I watered too much at one time. :-( Anyway, it doesn't appear that there's a remedy. Hopefully I'll at least have a few edible tomatoes.
Has anyone else here had to deal with BER? If so, what was the outcome? Were you able to salvage any of your tomatoes or somehow cure the rot?

A glimmer of hope! I read that a cup of lime mixed w/ a gallon of water can help with BER. Anyone ever tried that remedy? I'm about to. I'll report back with results. :)

My tomatoes (some of them) got BER but eventually it went away on it's own :) I didn't do anything about it

ally99,
Lack of calcium is the proximate cause of BER, but it's pretty rare that there is actually a deficiency in the soil. Usually the ultimate cause of BER is inconsistent watering, which causes the Ca to be unavailable to the plant. So adding Calcium may not fix it.

Regarding the watering - it's not usually overwatering that is the problem with BER, it's inconsistent watering in which the soil is allowed to dry out around the root hairs. You don't mention if that 1.5 inches a week is giving you deep watering? Some people water daily for just a few minutes at a time, but watering for a longer period less often might be better (along with mulching). Perhaps this is exactly what you're doing, you don't say in your post, but you want the soil to be damp down about a foot after watering.

Good luck.

Thank you ausbirch. I appreciate your thoughtful response. I have mulched (sadly I used wood chips to mulch and later learned that was not the best choice...still a noob and making mistakes...on that note, I wonder if the wood chips could be affecting the nutrients in the soil enough to cause BER?) I water 2x per week w/ a drip hose for about 40 minutes. Does that sound about right?

Its early too and ber tends to go away in later season

Sounds pretty good to me, ally99. Exact watering regimes are of course tailored to your specific garden conditions - how quick your soil drains, amount of organic matter (compost etc) in the soil for water retention, temp, humidity and all that stuff, none of which I can know.

If it was me I'd check that the soil was moist deep down after watering (dig a little hole with a trowel) and then check midway between watering periods to see if it's maybe getting too dry in between. Perhaps for your soil at this time of year every second day will work better. There are general principles but beyond that its a matter of sussing out what works best for you because every garden has its own set of conditions.

And as others have said, it may go away as the season progresses. Adding garden lime won't hurt unless you overdose (but if you change more than one condition at a time you'll never know which one worked ; ))

And......some varieties are a lot more prone to it than others. I NEVER get blossom end rot on my tomatoes, but several years ago I planted some San Marzano for sauce making. They had it a lot.

I had the same experience as calliope with San Marzano, so much so that even though they were tasty I haven't bothered growing them them again.

Actually I'm tempted to give them another try this coming summer now that I'm on clay soil.

Thank you all SOOO much for the glimmer of hope! :) Fingers crossed my tomatoes heal nicely. :) I'll report back on how the remedy worked. Hopefully I'll see a difference in a few days. :)