Sharp sand drainage properties
I wonder if someone could clear something up for me.
I'm sure I've heard of sharp sand being used to improve the drainage qualities of soil, so today when potting a new plant I added some to the compost. But when I started watering it the water just pooled on top for a while - much longer than with my other plants which don't have added sharp sand.
So I conducted an experiment - I took two identical pots, added soil from my garden to each, but to one pot I added a good trowel full of sharp sand and poured in a pint of water to both at the same time. The pot without sand had water pouring out of the bottom almost immediately, whereas the sharp sand pot took three or four seconds longer. Pools of water formed on top of both pots and disappeared at about the same time.
Not an exact science, admittedly, but it suggests to me that sharp sand is not to be used for improving the drainage qualities of soil. Is that right?
Thanks in advance.