Crushed granite as aeration?

[hyposomniac]

I would love to know what happens with using the gravel for aeration. I think it could work like Perlite - Perlite works because it doesn't compress and keeps the mix from compacting. It creates spaces for air and the irregular surface has lots of pores for air. But perlite is closed-cell just like gravel - aiir, water and roots cannot get inside the chunks of perlite.

Gravel could work the same, with the one difference that it's much heavier. I'd be worried about the weight actually pressing down on the lighter elements in the mix like the fibrous peat or coir strands and crushing them. it probably depends on the exact rock too, if the gravel has a smoother surface than perlite it won't work. Rocks with a rough surface like lava rock are used in soil mix.

https://buildasoil.com/collections/aeration/products/small-black-lava-rock?variant=12367261728885

FWIW, I love perlite, cannabis loves it, I would pay whatever it costs to get it

Interesting..I did not know perlite was closed cell

 

[Teddybrae]

I just mixed 1 tonne gravel (basalt/granite nominal size 1mm - 3mm) into 4 tonnes basalt soil amended with compost animal manure etc.
Will it become compacted?
We will see ...

 

[Klompen]

Extremely fine rock dusts are potentially great sources of minerals but totally not suitable as a means of providing aeration. Unless the rock is fine as flour, its going to take a very long time to break down. If you want a cheap way to make a lot of rock dust you can heat river rock up in a fire or furnace until its red hot and then quench it in water. It will shatter the rocks but at the very least a face shield should be worn to do this as they sometimes explode a little bit. Also if you can find a store that cuts granite counter tops they probably have more buckets of dust than they know what to do with. I highly recommend adding some rock dust to your soil mix, but don't count on it for aeration because it generally does the exact opposite.

 

[St. Phatty]

I just mixed 1 tonne gravel (basalt/granite nominal size 1mm - 3mm) into 4 tonnes basalt soil amended with compost animal manure etc.
Will it become compacted?
We will see ...

What container & tools do you use when you're mixing that much soil ?

 

[PaulieWaulie]

I have some granite grit, I think they are 1/8"? Ive been adding 2 cups per cubic foot among other things. I wouldn't make my mix 33% granite grit though!