More lime will not help because the calcium would take too long to become available. BER is not from lack of calcium, but from lack of mobile calcium in the plant. Here's a thread I like. Scroll down the thread to Al Tapla's explaination.

http://forums2.gardenweb.com/forums/load/contain/msg0514510630172.html

This year I had som BER on my only SIP, and I threw everything but the kitchen sink at it including; calcium nitrate in the reservior, calcium nitrate foliar spray, gypsum in the reservior, and Texas Tomato Food in the reservior, which has extra calcium in it. My BER stopped (for now) fairly quickly, and I only lost about 10 Red Brandywines. After everything I did, still not sure what stopped it. Might have stopped by itself anyway, which is usually the case.

BER is not just calcium related - it is a combination of lack of calcium availability and uneven watering practices. Maintaining even soil moisture (no droughty or dry periods followed by excessive or heavy watering) can reduce the problem significantly. Also any cultivation in the immediate area can exacerbate the problem as it damages necessary feeder roots that transport both nutrients and soil moisture. Also fertilizing with a low nitrogen/moderate phosphorus fert can be helpful as well.

I had a problem with BER also in one of my Grow Boxes. I checked with the local nursery for lime, but they suggested Epsom Salts. I added a handful into the water reservoir, and the BER started to go away. I add a handful about once every 10 days or so, as the water changes out. The BER is greatly reduced. Most of the fruit now is clear.

It's odd that the nursery recommended epsom salts, gjshawk. In general, you should avoid excess magnesium, potassium and ammonium nitrogen if you're trying to curb blossom end rot, since all three compete with calcium uptake.

They told me that it was a magnezium deficiency that caused the BER. Whatever the cause, the salts seem to have had a big positive effect on my tomatoes.

I'm glad that you solved the BER problem, gjshaw, but, In all of the university research/recommendations that I've read, I've never seen BER tied to magnesium deficiency. On the other hand, BER is strongly tied to calcium deficiency (in the fruit), and excess magnesium has the potential to compound the problem. If your plants were suffering from magnesium deficiency, there should have been foliar symptoms (yellowing between leaf veins, for example).

This post was edited by shazaam on Mon, Aug 5, 13 at 13:29

I was originally looking for dolomite lime. Nobody around here (western Colorado) seems to have it. Next year I will find some before I prepare my mixes. Dunno why the epsom salts worked, but that's the only thing I have added. The leaves are fine, nice and green. I'm still getting some BER from the one plant, but not nearly as bad as before.