potting mixes

B & G Julian bgjulian@internode.on.net
Mon, 28 May 2012 03:47:38 PDT
I usually mix my own potting mix as required in batches of 50 litres 
using a concrete mixer to blend the ingredients of composted hammermill 
pine bark,coarse washed quartz sand,perlite,dolomite and  an 8/9 month 
slow release fertilizer. This mix is a basic one for both herbaceous 
perennials,bulbs/corms as well as seeds and I usually have good results 
for all of these plants. Last August I was potting up Helleborus x 
hybridus seedlings and had a lapse of concentration which was not 
noticed until some weeks later when the potted seedlings started to 
grow,some 1200 tube pots were done at the same time and  one of the  
mixer loads slow release fertilizer was accidentally omitted.The 
resultant seedlings without fertilizer are now barely half the size of 
the fertilised potted plants.I will hopefully not do this again.Some 
years ago I was buying premixed potting mix in 1 cubic metre batches and 
results were so poor I started to mix my own,much more effective and 
economical.This is in Tasmania where Winter frosts are -3 C to -4 C 
degrees and Summers can reach low to mid 30C,hottest was a couple of 
years ago when disastrous bush fires hit many parts of mainland 
Australia.Gordon Julian

More information about the pbs mailing list