Tomato problem

[Gardengirl]

Can anyone tell me why some of my tomatoes are developing 'flat  black bottoms' (if you'll pardon the expression ;D)  I don't  understand it as I have had loads of lovely healthy ones. 

I have transferred them into my greenhouse as they are in pots and were getting demolished by high winds.  The variety is 'Alicante'.

Any help greatly appreciated :)

I can post a photo if necessary.

[Gardengirl]

[john_miller]

Blossom end rot. Caused by insufficent calcium getting to the tissue. This in itself is a sign of lack of water at some point.

[tim]

Beat me to it by 3 secs, John!!

http://www.allotments4all.co.uk/yabbse/index.php/topic,12180.msg112861.html#msg112861

[Gardengirl]

Many thanks John & Tim :)  I suppose I should have done some reseasrch on the board, but it takes forever so quicker to ask a fresh question ;) :)