Magnesium is similar to but generally at a given pH more soluble than
calcium. I wouldn't become obsessive about magnesium which would be easily
covered by a spray of Epsom salts, and which interacts with potassium when
making up plant feeds.
Iron is especially knocked by pH and if plant colour is a problem water with
iron sequestrene.
I'm somewhat mean about buying espensive chemicals and in a hard water area
used to recover the green leaf colour of house plants (in about 1 week) by
adding a teaspoonful of cheap ferrous sulphate to a pint of water. Its much
cheaper than sequestrene and was more cost effective at this level.
Lawn grass seems to tolerate high levels of ferrous sulphate when applied as
a moss killer so its worth trying.
I leave it to others to give a correct dose. I would try 1ounce per square
yard around a shrub and observe closely.
Regards
David T.
"Kay" wrote in message
...
In article , Dwayne jenco@st-
tel.net writes
Try to locate someone there that can do it for you. The cheapest might be
at a University that teaches horticulture, or someone who makes his living
selling things for the garden. I am in the U.S. and just take it down to
the University Extension Office that is located in just about any town
with
a population of 4000 or more.

Blimey. In the UK, 4000 is classed as a village (except in the remoter
areas of Scotland), and would be lucky to have its own post office, let
alone a University Extension Office.

Just goes to demonstrate our much greater population density.
--
Kay
"Do not insult the crocodile until you have crossed the river"