Hopefully someone else can verify what I've said. I experienced the same problems last year in my container tomatoes and not so much on my in-ground ones.

Odd, your member page shows you're in zone 7 but it doesn't show up with your user name on the screen! I thought if it was entered it was always shown! (Not your fault, just something I noticed.)

I agree with WF, that it's very probably the fluctuations in soil heat that occur in most outside containers, as well as prolonged heat that is too much for the plants to handle. All my self-waterers are white, and I think any colored containers are likely to have hotter contents.

So basically, yes, use lighter colors to keep your tainers cooler. I've seen white trash bags on the surface of the potting mix to keep it cool as well.

"For vegetables and tomatoes, mix two cups of dolomite or hydrated lime into the top 3-4 inches of potting mix".

Than add the fertilizer:

"2 cups of dry fertilizer or 3 cups of organic fertilizer in a strip in the trough."

No additional calcium is needed. BER isn't caused by a lack of calcium in the soil but by the plant's inability to use that available calcium as needed due to plant stress. Stress can be caused by many things including the soil temps already mentioned. Other factors can be too much N, too much water, inconsistent soil moisture levels, weather fluctuations, pests, etc. There is good FAQ here on BER causes.

Dave

Do NOT use hydrated Lime. This is highly reactive and can do more harm than good.

I don't know how large a "handful" is but to be more precise, you need to add 2 full cups of dolomite Lime per 'Tainer. I suspect your "handful" came up far short of that amount. Out of 32 tomato plants last year, I only had minor BER issues on two plants throughout the entire season.

Raybo

I have two huge heirlooms growing in EB's in the backyard (black plum and black Kim) the black plum started developing BER on all the new tomatoes and the black kevin was starting to get it as well so I searched the web and what kept coming up was add a cup of hydrated lime with a gallon of water. Well I did just that and I came out this morning and my plants are drooping over and look like they haven't had a sip of water in weeks. I added more water to try and flush the hydrated lime out but I don't know what to do/ if I've killed my tomato plants I've worked so hard on all season! please help!

My plants don't seem to know that they're missing the lime. I think it's possible that adding lime is much like adding egg shells, crushed up Tums, spraying milk, and so many other tales.

Sorry, but I don't care what the Earthbox website says. They say you can plant 2 Indeterminates in their containers. Good luck with that. My homemade swc's have about the same cu ft space as theirs and I only plant one per container. When I pull my plants after the 1st hard freeze, the roots have taken over all the available space even down into the reservoir.

Just my observations. Not trying to ruffle any feathers.

So , I think by overwatering that alkaline solution possibly can be lowered back to normal.

The purpose of adding dolomitic lime is that peat tends to get very acidic so the lime offsets that. if the mix becomes too acidic it will prevent the uptake of nutrients and BER and other bad things will happen. I use a weekly addition of one teaspoon of calcium nitrate in the watering tube each week to keep calcium readily available.

Growing one indeterminate tomato or two per box is up to the grower. Earthbox recommends two based on total production per box.

Bonide makes a product called Hydrated LIme which is dolomited and I often use it instead of two cups of reg dolomite when I can't find anything else. Cheap, easy to find and works fine.

I have 4 Eearthboxes with tomatoes. 2 plants per container. The same media, amendments and fertlizer. Glacier and Beefstake have no BER, Zarnitsa - almost every tomato has BER, Black Krim - some BER, some catfacing.
The same cultivars growing in the raised beds show no BER. I assumed that Zarnitsa would appreciate some hydrated lime (per Earthbox instructions) but it matybe was too much