Look for "A1" Grit which is a graded granite product with angular surfaces. It is used in roofing as a mineral coat. Size around 1 mm. to 0.5 mm. I use it to cover seeds to prevent washing and discourage fungus gnats. Around here, feed stores carry it. Richard Vista CA -----Original Message----- From: pbs [mailto:pbs-bounces@lists.ibiblio.org] On Behalf Of Jyl Tuck Sent: Sunday, November 16, 2014 12:02 PM To: pbs@lists.ibiblio.org Subject: [pbs] Sand for potting mixes I'm new to the PBS but not to a love of plants. I have used a cheap easily found chicken grit for the plants that I have needing quick draining soil. So when joining this BX I have used the same chicken grit in pots with bulbs after looking up their needs and their environments from where they came. It has worked well so far. I tried sand from the Fraser River and local fresh water lake beaches and store bought and they always compacted or dried out quickly in the past which led me to the chicken grit. I don't know if this would work for your iris,( I'm no expert ) but my plants have always thrived even in my flower beds putting a layer under Eremerus,ect. to save them from our rain forest B.C. climate. I struggled looking for proper soil requirements ------ not wanting to waste money or plants, so maybe this will help someone else. I've traded seeds for years to the UK and always labelled them' Seeds of no commercial value' without any trouble. jyl