Hi Gang, Are any of you using Heydite for growing bulbs? I started using it a year or two ago for succulents and cacti, and really like it. This past year I started using it in the mix I make up for germinating bulb seeds, especially seeds of bulbs from dry areas (e.g., Sough Africa). Heydite is often called porous shale, but I think it is shale that has been baked and expanded (the way perlite expands). I like Heydite because it seems to hold more moisture and air that is readily accessible to roots-but it drains quickly in a mix of coarse sand, perlite, humus, etc. I don't find much about Heydite on the Web. It seems to come in 2 sizes: chunks about ½ inch across, and smaller pieces about the size of kitty litter. I use the smaller size for seedlings, but other folks tell me the larger size is perfect for plants in gallon cans. It is durable and does not crush, a friend told me it is used on race tracks at some high schools in this area (greater Houston, TX area). I buy a large bag (about the size of a 20 lb. bag of perlite) for about $16.00. LINK: Photo of small bag of Heydite (small size particles). http://www.growhere.com/growingmedium/heydite.htm LINK: Expanded Shale Article (I think this is where Heydite comes from). http://aggie-horticulture.tamu.edu/extension/… shale.html