There are a bunch of discussions on BER and almost all of them address that BER isn't usually a lack of calcium per say, but rather, it has to do with the plants inability to properly distribute calcium throughout the plant. This generally happens from lack of water, but you are growing in earthboxes so I wouldn't normally think that was the issue here.

So trying to avoid stating the obvious, but are you sure that the earthboxes are setup correctly and that the soil is wicking up sufficient water from the resovoir? I'd open the tops and pull the mulch back to see how moist the soil is underneath. If after you check that, you notice the soil to be fine water-wise, then I'd check for calcium problems.

A lot of people here are more experienced with earthbozes than I am, but generally the planting mix + lime should be more than sufficient for calcium needs of the season - or so I'd think.

If you are on Tville, there is a nice thread going discussing exactly your issues. I'm in Ray's earthtainers and one earthbox this year and have had a serious issue with BER, especially with Stupice and Goose Creek. Others, not so much...so there appears to be a varietal tolerance or intolerance as it were, on the BER issue.

The short version of the lengthy thread is that liquid calcium in the water looks to be something the plants can quickly utilize and, my experience only, is that it appears to work. I've been adding a liquid calcium magnesium product with every refill, and BER has slowed dramatically. I also addressed the other issue I was concered about, extreme heat, by raising the tainers off the ground (I was on a driveway), 50% shade cloth and using a bamboo shade to shade the boxes themselves from directly sunlight. (They were hot to the touch, so I suspect the roots were getting too hot). With multiple changes, it is difficult to say to what degree the calcium is helping, but something is helping, or more likley, a combination of factors is helping.

Also, you can go the the earthbox forums and type in "the snack" and read scads of comments about liquid feeds and they are mostly very positive.

Good luck.

I am pretty sure I've set up the earthboxes correctly, but I'm going to take the advice and check. In NE Mississippi we have had an unusually hot early summer. It's been in the 90's and very humid. The earthboxes are on a concrete surface. I'll check the boxes and see how hot they are, but I'm certain they must be hot. I appreciate the feedback and the links to other forums. You can check out my garden setup on YouTube. Type in caledoniagardener and my video's are there.

"They were hot to the touch, so I suspect the roots were getting too hot"

You're right, I wasn't even thinking about excess heat at the roots, but that could definitely be a major contributing factor. This would almost never be a problem for me where I am in PA zone 6, but where you guys are it would surely be a concern. Even if you don't think they are getting to hot, it couldn't hurt to raise them up (could probably even just use 2x4s) and shade the boxes somehow.

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Calcium nitrate. It's cheap and simply dissolves in water.

High or very high (K)Potash levels w/ cause BER also.

Our favorite tomato expert Carolyn137 wrote an excellent response to a question about Blossom End Rot (BER) and I am quoting it here:

With BER there is NO problem with absorption of Ca++ though the roots. The problem is maldistribution within the plant that can be induced by a number of stresses which include uneven delivery of water, too much N, growing in too rich soil, too hot, too cold, too wet, too dry you name it.

As the plants mature they can better handle the streses that can induce BER so usually it goes away.

The two exceptions are first, if the soil has NO Ca++ as confirmed with a soil test, and that's a rare condition, and second, if the soil is too acidic in which Case Ca++ is bound in the soil.

Again, adding lime, egg shells and on and on can not and will not prevent BER b'c absorption of Ca++ thru the roots is OK.

Paste tomatoes are especially susceptible to BER and I think someone in a post above mentioned that.

If you go to the top of this first page and click on the FAQ link and scroll down you'll also find an article about BER in case some of you have never looked at the FAQ's And there's some darn good articles there as well, but I wouldn't pay any attention to the variety list b'c it's way out of date.

The old information about BER being caused solely by lack of soil Ca++ has been shown to be wrong with research that's been done in the last 20 years or so, but it's going to take another generation before the real story gets into books, websites, magazines, etc. Most of the better websites already have the correct information.

BER affects not only tomatoes, but peppers, squash, cabbage, cauliflower, etc., and it's a huge multimillion dollar problem for the industry, which is WHY all that reasearch was done. For instance, when tissues were taken from a plant that has BER fruits and was assayed for Ca++, the normal level of Ca++ was found, it just wasn't getting to the blossom end of fruits. And there's also a condition called internal BER where the fruits look fine, no evidence of BER externally, but when you cut open the fruit the inside is black

Hope that helps

I suppose that if your roots are too hot, that could affect calcium uptake and therefore distribution. In some cases a foliar spray does help. But, usually, as Carolyn mentioned, time is the best help.

Betsy

Here is a link that might be useful: FAQ page on Blossom End Rot

I'm reading a soil test report in front of me that was just done by UMASS. K20 (k) last number in X-X-X 5-10-10 etc. My (k) level is high (220 ppm) on this sample.

UMASS says... " Sideressing w/ calcium nitrate and avoiding excessive potash (k) levels will reduce the chances of blossom end rot"

Since i have been using Dyna gro "Protekt" from seedling to maturity i have bigger, healthier, stress tolerant plants with a big reduction in BER.
Cal Mag is another product that helps in the BER battle.

A steady application of ACT's helps your plants fight off many other diseases and insects.

i use one ounce per gallon of the calcium chloride to clear up my blossom end rot problem, in my indoor growing tomatoes- this is the stuff you use to put on your sidewalk to melt the ice in winter - you water the plants with it -
it works great. add a lot of bonemeal to your growing mix and some compost to introduce organisms that will feed on it to release the calcium - pm.