pumice
Ina Crossley (Wed, 21 Oct 2015 11:41:38 PDT)

Growing Zephyranthes and Habranthus and various Amaryllids, I have had a
real problem with Staganospora curtesii. I realised that it was winter
time which seemed to be causing the biggest problem. As the bulbs never
got dryish. Being outside.

So I changed all the containers to a mix of 2/3 pumice and 1/3 potting
mix. Which did not give much of an improvement. So even though it was
a huge job I decided to redo the whole lot again this year using pure
pumice. New Zealand pumice has been washed but still has lots of fines
in it. So I rewashed every bit of pumice I used. Started with a cubic
meter of the stuff, but now buy bags of it as I am nearing the end of
the job. I now use 7mm pumice, although the cubic meter lot was smaller.

I add slow release fertiliser to each container. And the bulbs are
doing fine. Yes, they grow more slowly, but they are healthy.

Quite a lot of the sick ones I threw out and have started growing fresh
lots.

I have not had to water much as winter time is a wet season. But once a
week I water with fertiliser. And now going into summer, I water when
required. Also I have passed tape through holes in the side of the
containers to help drain that water table at the bottom.

A few like Z. atamasco and Z. simpsonii have their own requirements so
those I now grow in the bog garden.

And some desert ones, I have put the containers against the house so
they stay drier than the others.

I grow lots of other bulbs which do not get pure pumice.

I think we all have to find what suits our climate.

Auckland has a subtropical climate and it gets humid in summer.

Ina Crossley

New Zealand