Hi, I find it interesting when we revisit this subject every now and then. What I've noticed is that we are such a diverse group from so many climates and situations that what works one place does not seem to work as well other places. In the beginning of my bulb addiction I tried whatever anyone suggested. Perlite made me cough so I abandoned it. Someone recommended cat litter once. I tried it unsuccessfully ( I did look for one without a lot of additives.) I searched everywhere for Turface, calling around and finally found some that I could purchase I think as Profile clay soil conditioner or perhaps it was aquarium mix. Nothing has ever grown very well for me in it so I've stopped looking for it. Someone recommended decomposed granite so I got a bag of it at a landscape supply store. It was so heavy and clumped too and in my wet winters I'm sure did not generate the air porosity I needed. Red lava rock easily obtained in Northern California was not a success either although I think in a bed where I mixed it in bulbs may have done better in later years so perhaps the rain leached something out that was not good in the beginning. When I first started growing bulbs I read that 1/2 sand and 1/2 peat moss was very good. So I bought sand and didn't realize it needed to be coarse. The definition of "sand" to me was what you had in your sandbox as a child or saw at the ocean. I am sure what I added to my mix resulted in less air in the mix instead of more. I never could find grit when I was looking for it when everyone talked of adding grit to the top of their pots. What I use now is coarse sand (which is like small pebbles or rocks) easily obtained at landscape stores and even available here away from civilization and pumice which I can get in bags at Orchard Supply and a place called Harmony Supply in Sebastopol. Those places are a couple hours away so we buy a lot of bags when we go. And it isn't cheap either. You can also get it at Charley's Greenhouse Supply but it is even more expensive there (although in different grades.) What I'm looking for is something to add air porosity to my mixes during my main growing season when it rains a lot and temperatures are cool. Most of the bulbs in my collection are winter growers. Sometimes I add fir bark or even redwood compost and a handful of coir too even though I've been told that the salt content in it can be very damaging for some plants. I loved Bob Werra's description of his Moraea mix when he asked and answered the rhetorical question about why he used what he did with, "just because." There are a lot of ways to grow bulbs and if you keep trying you find what works for you. I seem to recall John Lonsdale who brought up this whole subject telling us he used composted peanut hulls with his perlite and that obviously isn't something easily obtainable here. I'm don't mean to discourage all the suggestions since it is fascinating to hear what works in different places, but since we probably have all levels of experience in our group would like to point out to the beginners in our group that additives are often used to create air spaces in your mix so the bulbs won't rot and to do that the particles have to be different sizes. That's why perlite when it gets to be mostly fines or fine sand is a problem. Using some of these things can create bog conditions with very little air. Mary Sue