Marieke Mendes
Mon, 02 Aug 2010 07:46:15 PDT
Good day,

I am a bit late on the subject but just my two cents on coir.  Don't be
scared of it, work with it - in my opinion there is no ideal media on its
own, it depends on how you water and fertilise as well.

We do tissue culture and potted plants (Zantedeschia /calla lily, which hate
waterlogged conditions) and I would almost exclusively use coir as coco peat
if it wasn't so expensive.  When I plant tubers in pots I re-use a 50:50
fine coir and bark (6 mm) mix after cleaning it and then mix it with fresh
coir and a bit of sand (10 %) just to add drainage and I like to think a
little silicone is important (I am still experimenting with the sand).  The
mix is quite fine, but we irrigate (with water solluble fertiliser -
fertigate) accordingly so that it doesn't become overwet.

If you use "unbuffered" coir you need to add calcium and magnesium as Steve
suggested in a 2:1  ratio, this is very important to establish a good
nutrient balance as it affects availability of some ions.  You can easily
use calcium sulphate (as gypsum) and magnesium sulphate (as Epsom salts)
which are both obtainable in small quantities at most pharmacies. For one 5
kg block, making approx 45 l medium when loose add about 50 ml gypsum and 25
ml epsom salts.  Soak until coir block expands (approx 3 hours),mix
thoroughly and let water drain out - we actually do this in a bath outdoors
and pull the plug to let the water drain.  If you are very worried about
salt, rinse the medium with water twice (after expansion) before soaking
with above mentioned calcium / magnesium mix.

Just don't overwater and fertilise regularly and you should have very happy

Marieke Mendes
From sunny South Africa highveld where winter bit quite harshly (all my
albucas are brown) but seems to be over already.  I dare lift the frost
cover now...

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