Keith,
Ca and Mg are absolutely essential plant nutrients.
Might I suggest you take a look at the MSU RO formula, and use it as
your guide for complete plant nutrition:
http://www.firstrays.com/MSUFert_RO.htm
Ray Barkalow
First Rays
www.firstrays.com
-----Original Message-----
From: keith kent ]
Posted At: Monday, June 22, 2009 5:56 AM
Posted To: rec.gardens.orchids
Conversation: RO & Feed
Subject: RO & Feed
Is it necessary to supplement Calcium & Magnesium when using RO , so i
suppose what i am asking is does a standard feed contain enough ?
I am reviewing my feeding regime as my water pump has packed in,
questioning
quailty of my rain water and some leafs of plants are turning
yellow/bleached from the end of leaf moving down .
At the moment i am using a standard 2-1-4 granular feed and adding
sulphate
of ammonia to make it 4-1-4 and supplementing Cal & Mag.
I mix 15ml of the feed ,5ml SofAM, 5 ml Cal , 5ml Mag add this to my
main
solution ( 100ml water) then gradually add this to 80 lts until my
required
strength is reached depending on time of year,then alter the ph to
6-6.1.
The bleached leafs effected my Masdevallia the most , but it is
appearing on
some Coelogyne & Den tips.
So i am thinking of simplyfying my regime to the 4-1-4 only and
altering
the PH .I am also concidering using a standard liquid feed /adjusting
the
ph.
Any advise is apprecciated.
Keith