Where do you all get the sand you use to encourage good draining for South African bulbs? I've got some that I picked up at Home Depot, but I think it's too fine - instead of promoting drainage, it seems to hinder it. But it's the only sand I've been able to find in Home Depot - it's in the same section as the concrete mixes. The only sand they have in the gardening section is decorative; it comes in very small bags at very high prices. Thanks for any suggestions! Jennifer