Zeolite And Bonsai Making the assumption that the original post was from an Australian, I will say that there are two commercial natural zeolite mines producing product in Australia of the clinoptilolite form that is commonly used in gardening around the world. I am involved with one of these so in the spirit of the forum I will not mention its name. A quick web search will find one of these two. These Australian natural zeolite are harder than overseas deposits being in the mid 5âÂÂs on the mohs hardness scale out of 10 compared to 3âÂÂs and 4âÂÂs of those for example from Asia and USA. Typically being this hard when incorporated into a soil media zeolite will last in its processed particle size for hundreds of years making it very suitable for this use. We have bonsai clubs in New South Wales now using our product in a 1 to 3 mm particle size. This typically is included at 15% by weight into the potting mix. Also include your other materials such as organic matter of various forms, manure, slow release fertiliser etc. Zeolite if what is actually produced in Australia is hard enough to give the potting media texture plus the usual thing zeolites offer in the aiding water retention, nutrient holding and hosting friendly soil microorganisms

My county agent sent me this link because I have been asking him about granite dust as a source of phosphorus. Having read both sides in various places I decided to test it on my own. When taking soil samples for spring I dug under a pile of granite dust that had been near my house for several years so see how much, if any, phosphorus had leached into the soil beneath. I was careful to exclude any granite dust from the sample. My fields are seriously depleted in both potassium and phosphorus from cotton/pine plantings over the years. The sample under the granite heap had over three times the phosphorus that all other fields had - almost up to the necessary level for planting. Our farm is just south of Elberton, GA - "The Granite Capitol of the World" - so granite screenings are available and relatively cheap. Now if only I can find a cheap and organic source of potassium, but that's another thread.

I am just having a look at this old thread and will comment only on the zeolite. The natural zeolite is of the clinoptilolite mineral referred to here I would suspect. It is formed from volcanic ash that falls into a saline lake. It has an order of preference for cations. At the bottom is sodium then ammonia then things like potassium, magnesium, calcium and at the end the high preference are heavy metals such as lead, cadmium etc. What this means is that clinoptilolite will more likely hold and not exchange out those higher in its order of preference. So it will not exchange lead for sodium or ammonia for sodium. We mine and process clinoptilolite natural zeolite and sell large quantities into the swimming pool market to replace the filter media in sand or diatomaceous earth filters. In salt and chlorinated swimming pools it works the same. For aquariums the clinoptilolite, natural zeolite is very suitable but I would still blend in activated carbon. The zeolite is good for molecules and individual atoms of up to 120 in molecular weight and then activated carbon is better for anything larger. Organic molecules you also wish to remove may be quite large in size. Zeolite will be great on removing ammonia and still allow table salt to be used. As stated above, it is true a brine of very concentrated table salt will exchange out other cations such as ammonia as it will simply overwhelm them. You could also just buy more zeolite! Natural zeolites vary in hardness and any preloading with cations. Zeolite from young deposits of only a few million years of age will be soft and chalky and likely still be loaded with cations for example of potassium and calcium. Older deposits hundreds of millions years in age are harder and less loaded with cations. The latter is more suited to aquariums. If in doubt when you buy some, sit the zeolite in a bucket of water of a heavy mixture of table salt for a few hours to a day before loading your filter (with some activated charcoal).

Most everything I find on the use of Zeolites as soil amendments is by those with a vested interest in selling the product. Most of the research on use of Zeolite indicates that in soils lacking adequate levels of organic matter they can be beneficial and in soils contaminated with toxins they are useful. However, I can find nothing that tells me that in soils with adequate levels of organic matter adding Zeolite actually does much to make that soil any better then the organic matter.