I would guess it to weigh about 1/3 more than most commonly used container soils.

If you've been reading closely, you probably learned that size matters. You could replace the granite component with perlite or anything else that is durable, fairly nonabsorbent, and is the same size as crushed granite, so long as it's not phytotoxic.

I like the granite simply because I find it's pre-screened size perfect. I/you can up the volume of Turface/decrease granite to increase water retention, or up the granite/decrease Turface to reduce water retention. The combination gives the soil a good deal of versatility, but it happens to be the size of the granite and not it's other physical properties that make it useful in adding versatility. With Turface, it is its tremendous porosity and ability to retain water, along with its appropriate size that makes it so useful.

Good luck! Merry Christmas, too!

Al

I've tried a number of mixes and found that particle size tends to have a greater effect on porosity than the material used. I don't see why you couldn't shuffle the ingredients as long as the materials are screened to remove fines. One product I really like is calcined diatomaceous earth. It's sold as an oil absorbent at Napa auto parts (part #8822). It's a lot like Turface but even more porous/lightweight and has a gray/white color. I think I payed $7.50 for a 6 gallon bag (IIRC). Perlite is lighter yet, but I don't like how it floats. It's also been said to have a relatively high fluoride content which could be harmful to some plants, although I don't know how true that is.

Perlite is fairly high in fluoride, that is true. We've talked about calcined DE products like Axis and Play Ball and there is no reason not to use them. In fact, they are superior to Turface in a couple of areas.

While what you said about porosity is true, the beauty in using products like calcined clays and DE, is that they have tremendous internal porosity. That we can still maintain a particulate size and surface shape that promotes excellent macro-porosity and aeration, while taking advantage of the water-holding ability offered in the internal porosity of the calcined products mentioned is a great asset.

Al

I don't know if this will help anyone... I've been doing a fair amount of reading and searching, looking for an alternative to granite chips or turface I could easily acquire in my area. I came upon this website, and the information on medium is excellent. Link below...

Actually, I enjoyed the entire website... I'm not sure I have the knowledge or patience for bonsai, but the cultural information is indispensable... for me, anyway!

Here is a link that might be useful: Bonsai Mediums

Thanks for the assistance one and all (and hope your holidays are finding you well)! I think I'm going to go ahead and try tapla's mix per normal in a few pots, and change out the others over time (once I get a final assessment at max. weight for the deck:).

I do find Al's mix to be heavier weight-wise, but I wouldn't trade it for all the free bagged potting soil on the planet! It's indispensable for growing healthy root systems, and healthy roots make healthy plants and flowers!

I mainly use it for my vast potted bulb collection, and I can't say enough about the fact that since switching, I've experienced no rot or fungus whatsoever! Many of my bulbs are prone to rot and fungus... especially when potted in regular potting soils.

You're so funny, Al! But I do like the title! Gosh, I feel like I just got a promotion! :-)

I just can't help extolling the virtues of a product that really works... when you find a solution to a gardening problem, you just want to share it with everyone... and so, I do!

It's true... Al's mix helps promote healthy root growth, which in turn makes for healthy stems, leaves and blooms! It's made a huge difference in the health of my container grown bulbs!

Has anyone used gritty mix in really large containers? I have two huge containers that hold about 7 cubic feet. I'm nervous about the weight