Calcium plays a role, but as this snippet below shows, BER is more a
consequence of too much N ferts and uneven moisture supply.

"Cause

Blossom-end rot is not caused by a parasitic organism but is a physiologic
disorder associated with a low concentration of calcium in the fruit.
Calcium is required in relatively large concentrations for normal cell
growth. When a rapidly growing fruit is deprived of necessary calcium, the
tissues break down, leaving the characteristic dry, sunken lesion at the
blossom end. Blossom-end rot is induced when demand for calcium exceeds
supply. This may result from low calcium levels or high amounts of
competitive cations in the soil, drought stress, or excessive soil moisture
fluctuations which reduce uptake and movement of calcium into the plant, or
rapid, vegetative growth due to excessive nitrogen fertilization.

Management

Maintain the soil pH around 6.5. Liming will supply calcium and will
increase the ratio of calcium ions to other competitive ions in the soil.

Use nitrate nitrogen as the fertilizer nitrogen source. Ammoniacal nitrogen
may increase blossom-end rot as excess ammonium ions reduce calcium uptake.
Avoid over-fertilization as side dressings during early fruiting, especially
with ammoniacal forms of nitrogen.

Avoid drought stress and wide fluctuations in soil moisture by using mulches
and/or irrigation. Plants generally need about one inch of moisture per week
from rain or irrigation for proper growth and development.

Foliar applications of calcium, which are often advocated, are of little
value because of poor absorption and movement to fruit where it is needed. "

Source:
http://ohioline.osu.edu/hyg-fact/3000/3117.html

--
TQ

"Dwayne" wrote in message
...
| Have you experiences blossem end rot before? I did and was told to add
| calcium to prevent that, but that it has to be done during the fall
| preceeding the growing season you want affected if you use the pelletized
| calcium. The powdered form of calcium could be added as you do your
spring
| plowing, but it is more expensive as I recall.
|
| TQ said that the blossem end rot is caused by uneven watering. That could
| very well be true also, but I suspect it could be either of the problems.
| Have you had a soil test conducted on your dirt? Might be a way to
| determine which way you need to go.
|
| I had blossem end rot on my tomatoes and on my watermelons. I applied the
| pelletized calcium that year for the following season. I still had some
the
| following year, but not as bad. I assumed that I had not put down enough
| calcium, and we moved before needing to do any further correcting.
|
| Let us know what you find out.
|
| Dwayne
|
|
|
|
| "Ben" wrote in message
news:bYyJc.33734$od7.11803@pd7tw3no...
| My healthy tomato plants (determinate Roma and indeterminate cherry)
have
| set lots of fruit, and some of it looks just about ready to ripen. I've
| fed
| a couple of times with balanced fertilizer (most recently three weeks
| ago),
| and the soil is good and composty. Is there anything special to do at
this
| point with pruning, with the soil, with watering...? Should I add
calcium
| to
| pre-empt blossom end rot? Any suggestions! I'm in Victoria, BC.
|
| Thanks.
|
| Ben
|
|
|
|
|