All inorganic soil mix for beginners?

[Shane]

I'm thinking about trying an all mineral soil mix, which I've never done before. I'm looking for suggestions. I have pumice (about ¼-½ inch)
[EDIT] My "pumice" is probably better described as "lava rock" or "lava" (I believe what I have could more technically called "Scoria")
perlite, small gravel (crushed granite a bit smaller than aquarium gravel) and slow release fertilizer pellets. I was thinking I'd just do straight up pumice (with fertilizer) to see how it works. I have a Parodia picked out that I think should be able to handle any mistakes I make

What are people's thoughts on this? And any beginner advice in general on mineral mixes?

[bartab]

I know some people advocate all pumice but I find it easy to tip over in winds that I get here, and 1/2 inch pumice seems awfully large to me. I know everybody has their perfect blend and I have fun by trying different mixes. This summer I am using equal parts pumice, lava, and decomposed granite. These are all easy for me to find local so that is a factor. If I need to add soil for plants that need it I can just add to this mixture. Again, I’m not claiming this is the end all. I use liquid fertilizer when I water.

pumice, lava, granite

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mixed

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in a pot with a plant from Miles.

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[Steve Johnson]

I'm thinking about trying an all mineral soil mix, which I've never done before. I'm looking for suggestions. I have pumice (about ¼-½ inch), perlite, small gravel (crushed granite a bit smaller than aquarium gravel) and slow release fertilizer pellets. I was thinking I'd just do straight up pumice (with fertilizer) to see how it works. I have a Parodia picked out that I think should be able to handle any mistakes I make

What are people's thoughts on this? And any beginner advice in general on mineral mixes?

1/4"-1/2" pumice is way too big, but if you go to Sunset Nursery in L.A., they sell E.B. Stone pumice in the grain sizes that are smaller and more suitable to a soil-less mix for cacti. The crushed gravel you mentioned should be fine, and I'll recommend the 60/40 pumice-to-gravel mix I've been using with a lot of success since 2012. Forget about the perlite. As to fertilizer, I'm skeptical about slow-release ferts, so my other recommendation is Dyna Gro liquid fert -- something else I've had a lot of success with. My fert of choice is the All-Pro 7-7-7, although you can only buy it by the gallon which is kinda expensive. Such being the case, Dyna Gro's Orchid Pro 7-8-6 is the next best thing, available in smaller (and more affordable) quantities on Amazon. With soil-less mixes, you'll need to fertilize every time you water -- dilute 1/2 teaspoon of the liquid concentrate per gallon of water.

Here's Sunset Nursery's address and phone number:

4368 W Sunset Blvd, Los Angeles, CA 90029
(323) 661-1642

[bartab]

Thanks Steve, just ordered the Orchid Pro. The big container seemed a bit of overkill for me.

[keith]

That mix it look's good to me. I went too heavy on pumice and didn't work out so great. Depends on your climate what you can get away with. I'm using pumice mixed with gravel and a little left over lava rock which is just like regular rock it wont hold much water.

And for the top dressing I try and avoid the pumice it holds too much water and will cause the spines to turn brown with all the humidity around here.

Just the rock . Spines of some cactus wick water up from the soil . I use miracle grow for tomatoes diluted.

[bartab]

I love reading Xerophilia and Stone Eaters and I always want to tinker a little bit after going through it.

[Steve Johnson]

Thanks Steve, just ordered the Orchid Pro. The big container seemed a bit of overkill for me.

Glad I could help!

For those of you unfamiliar with the Dyna Gro products, there is a small advisory...

If your overnight lows go down into the 30s during winter, potassium salts in the liquid concentrate precipitate out and crystallize. Getting the crystals back into solution can be done, but it's kind of a pain. Unlike pesticides, Dyna Gro ferts are safe for storage in the house, and it's the best way to avoid that problem.

[Shane]

Thanks for all the replies! I see now my initial idea wasn't very good. I'll be looking into the suggestions. Definitely have some things to go on now

[DaveW]

For those in the UK Tesco Low Dust molar clay cat litter is now back on the shelves after disappearing for around 6 months.

https://forum.bcss.org.uk/viewtopic.php?f=1&t=170205

You could get Sanicat/Sophisticat from pet stores during that time that was similar but most got used to using Tesco's smaller grained version. However as they sell several types of cat litter and usually the cheaper ones (shredded paper, fullers earth) are no good for use in cactus soils, make sure you get the right one.

http://desertplantsofavalon.com/tag/sanicat-cat-litter/