Shmuel: I've used coir. There has been some criticism about high salt content present in coir. I usually give it a wash before using it. I think there are more expensive brands available that are thoroughly washed and all salt removed. Arnold On 10/30/12, Shmuel Silinsky wrote: I really like this thread!!! Mike wrote: >So I took equal quantities of six potting ingredients, >weighed each one, soaked it in water for six hours, poured off the excess >water, and then weighed the ingredient again. This told me how much water >it retained. Here are the results, with 1 = the amount of water retained by >sand. Maybe I am misunderstanding. I assumed equal quantities meant by volume. Water retained was by weight (which is great cause 1ml = ig). Just checking because obviously same weight of perlite and sand is a huge difference in volume. Is coir (coconut fibre) used in bulb circles? Shmuel Jerusalem Zone 9b