On Mon, 01 Jun 2009 20:56:26 +0200, bob wrote:

I'm in France at the moment and couldn't find Sequestrine (or sulphate
of ammonia, come to that), nor could I spot an equivalent product in
the garden centre here so I'll go with the vinegar for now until I get
back to the UK to pick up supplies.

After a new search in my garden center I'm hoping what I've found
today is the approximately matching stuff in France - 'KB-anti
chlorose'. It's a powder, the bluish colour of a corroded copper
roof, and seems to have the principle ingredients soluble iron - 3%,
magnesium oxide - 16%.

It recommends a 10 grm dose in 2 litres of water for a single plant
and then a watering in to take the solution down to root level.
Subsequently monthly if necessary - but I don't know how one would
gauge the neccesity. It's not cheap so I don't want to splash it
around unnecessarily.

Do you think a repeated use is a sensible insurance policy or likely
overkill?