>I meant to chime in earlier on the discussion about what type of sand to
>use in a potting mix. A friend of mine put me on to another soil amendment
>that does well for my cactus and succulents. It is called SoilMaster, made
>by Pro’s Choice. I was having problems with the sand I was using in this
>mix as it was holding to much water, causing some of the plants to rot off.
>I have not seen this problem since changing over to the SoilMaster product
>and was wondering if anyone has used it in their bulb potting mixes to get
>good drainage? Any downside to this?
Sounds like a type of calcined clay, like Turface, which I use with good
results.
The water-retaining properties of sand, though, are zero. I'm a compulsive
grower of cactus from seed (as the 600 seedlings in the upstairs bedroom
demonstrate), and have a small collection of asclepiads, all of which are
grown in pure sand ("play sand"). There is no moisture at all in any of the
pots right now. The humidity in the house is probably a sweaty 20 percent.
Where I got into trouble, with the stupid iris, was that it was growing in a
pot of sand, inside a propagator in the laundry room (extremely low-tech
here), and when the sand was watered, the water just wicked back up through
the pot. No way for it to evaporate. That's the reward of hubris, working
hand-in-hand with sloth.
Grit works really well for aeration (I don't use the d-word), but it should
be tasted first. (Maybe not in the store.) I understand that in U.K. one can
get fifty different kinds of horticultural grit, but here, poultry grit is
the choice, and some of it contains salt. I discovered this the hard way.
Bob Nold
Denver, Colorado