Lava rock and pumice shouldnt be this hard and expensive to find

Bigger picture there is also a sustainability question since perlite is mined. Looking at things from a permaculture perspective, we should look to use alternatives like pumice, rice hulls, or biochar.

There is also a health issue with perlite with all the dust it creates when mixing soil. Even with a hood and mask and glasses on, it was like a cloud of perlite smog every time I had to work with it. The Roots Organics perlite I used in the past was great but when I ran out of that and couldn't find any more locally, I had gotten a 4 cu ft bag from the garden supply and that shit was terrible. The perlite would crumble and collapse with little pressure and the grading was inconsistent.

Reefstein said:

I’ve always used perlite in the past. I’ve always heard actual stone is superior to perlite since it won’t break down and turn to concrete over years of recycling the soil. I want to reuse this soil for a long time and don’t want to deal with perlite breaking down and floating to the top.

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Ok, it does float, but it does NOT work it's way up through the soil to the surface unless you blast the mix with a high pressure hose.

Others say it breaks down and sinks and clogs drains. Which is it!? It floats AND sinks?

My no-till mixes last ~5 years max till the peat moss breaks down so much it is just sludge and gets spread on the soil gardens. Mainly from worm activity.

I have had long term plants (tree saplings), for 3-4 years and when finally up canned, or planted, the perlite in the mix was still well distributed and nowhere near dust. No worms in these cans.

I actually use perlite and pine bark fines as a mulch layer now. Put a layer of perlite down first and then pine bark fines over that. Light watering will cause the perlite to float up and stick to the fines and they seem to stay stuck rather than seperate. Easy to apply and easy to remove and reuse. This is for outside, of course. Most of my growing is outside.

Use whatever you like for aeration and what works best for you.

Wet

Use crushed oyster shell. Can get big bags of it at feed stores or tractor supply for cheap. Its sold as chicken "grit", will add the aeration you want, AND provide calcium/pH buffering as it breaks down over the years.

In a perfect no-till (indoor) world we wouldn't need to add an artificial aeration component at any cycle. Old growth forests and large scale no-till farmers don't add pumice or perlite or anything else to achieve their porosity goals. Instead through mineral particle and stable organic carbon aggregation through microbial soil life and other processes, drainage is afforded by the spaces between these aggregate particles, as well as the decayed roots that leave empty channels, the fungi hyphae, and the tunnels of higher life forms such as worms that eat them. This process takes a long time - like years with formerly lifeless soil.

But we're cannabis growers and we all want to grow product starting from our very first cycle with a new soil, so we include additives that improve drainage and gas exchange in our initial soil mixes. But the relevance of these additives should become less important as you progress in cycles, provided that you build your soil with the aim to increase carbon sequestration and biological activity in your soil from one cycle to the next.

Anyone ever look at the normal, original mineral based soil outside under their compost heap after a few years, even in a high clay medium? It undergoes a pretty radical transformation in physical properties. Pour some water on it, and you'll notice the water does not pool at all. Yesterday I was thinking about this while hunting for edible mushrooms in an older growth forest. I also collect soil samples, so moved the fresher dead leaf layer aside and the entire surface was covered with a thick white mycelial mat. Below that was several inches of humus intertwined with surface roots. Water percolates through this medium so quickly it's crazy, yet holds onto moisture as well. I collected samples and put them in my worm bins. I collect soil from field and forest all over the place in different environments to add as much diversity as I can eventually to my soil.

Great info @Northwood ! Ive been wondering about this mycelial mat. I live out in the woods, and I blow leaves off my driveway and yard close to the cabin, but I leave everything else. I have noticed when clearing out some foliage, that the leaves form a mat, and underneath is almost solid white. The leaves are 90% oak leaves, which I think I read are pretty acidic? Is this mycelium something I want to add to the coots soil ive got cooking outside? Thanks for the info.

GrassBurner said:

Great info @Northwood ! Ive been wondering about this mycelial mat. I live out in the woods, and I blow leaves off my driveway and yard close to the cabin, but I leave everything else. I have noticed when clearing out some foliage, that the leaves form a mat, and underneath is almost solid white. The leaves are 90% oak leaves, which I think I read are pretty acidic? Is this mycelium something I want to add to the coots soil ive got cooking outside? Thanks for the info.

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I'm a bit paranoid adding any outdoors stuff to my indoor soil directly, no matter where it comes from. Indoor conditions and diversity can never be like what you find outdoors, though we try. If you introduce any kind of pest or pathogen, they may thrive better under our artificial indoor environments than the beneficials. That's why I usually cycle everything through my worm bins first, in the hope I'll notice something wrong at that stage before introducing the castings to my plants as an innoculant. Adding the material to a cold compost heap and letting it age would help as well. None of those things eliminate the risk, but probably will lesson it.

That being said, it might be okay to add it directly to soil you have cooking outdoors. If your "cooking" soil is well oxygenated with great microbial activity, then any pest that depends on attacking living plants for its food probably won't be around for long. We don't know what species of fungi you have there creating the mycelium you see, and at worst it will do no harm. But if you get a bunch of Amanita Virosa mushrooms popping up in your next grow, please don't eat them

Keep in mind that I collect these items from outdoors to increase diversity of everything from nematodes, bacteria, protozoa, mites, and even larger things like isopods - not just mystery fungi species. I'm also careful not to include any fresh dead material; just from the mycelial mat layer and below within the rhizosphere of all those roots under it. Others may choose to buy products for innoculation that are proven to be safe and restricted to only certain beneficial species. But I'm a calculated risk taker, and humus from an old(er) growth forest is cheaper and likely more diverse than buying plastic bottles of concoctions shipped half way around the world.

Northwood said:

I'm a bit paranoid adding any outdoors stuff to my indoor soil directly, no matter where it comes from. Indoor conditions and diversity can never be like what you find outdoors, though we try. If you introduce any kind of pest or pathogen, they may thrive better under our artificial indoor environments than the beneficials. That's why I usually cycle everything through my worm bins first, in the hope I'll notice something wrong at that stage before introducing the castings to my plants as an innoculant. Adding the material to a cold compost heap and letting it age would help as well. None of those things eliminate the risk, but probably will lesson it.

That being said, it might be okay to add it directly to soil you have cooking outdoors. If your "cooking" soil is well oxygenated with great microbial activity, then any pest that depends on attacking living plants for its food probably won't be around for long. We don't know what species of fungi you have there creating the mycelium you see, and at worst it will do no harm. But if you get a bunch of Amanita Virosa mushrooms popping up in your next grow, please don't eat them

Keep in mind that I collect these items from outdoors to increase diversity of everything from nematodes, bacteria, protozoa, mites, and even larger things like isopods - not just mystery fungi species. I'm also careful not to include any fresh dead material; just from the mycelial mat layer and below within the rhizosphere of all those roots under it. Others may choose to buy products for innoculation that are proven to be safe and restricted to only certain beneficial species. But I'm a calculated risk taker, and humus from an old(er) growth forest is cheaper and likely more diverse than buying plastic bottles of concoctions shipped half way around the world.

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I've always thought forest humus would be a great addition to my compost pile. Living out in the woods I've wanted to responsibly harvest some from different areas around the property, but I've never got around to it. Your posts just motivated me to do some more research and try to get some into my compost pile before winter.

I ordered my lava rock and pumice from Build a Soil. It's not cheap, but it was worth it to me. If you go through this link, you'll get $5 off. Not much of a discount, but it's something.

Thanks for the explanation!! I'll just leave the coots mix as it is. I've got some nematodes from Natures Good Guys and mycorrhizae and mixed it in as well.
Ive got some extra compost left over, I could experiment with that pile

Outside stuff is scary, but it's worth it!

Rotting wood chunks are great mixed into soil for aeration, air and water retention, and a source of fungus and bacteria.

That humus layer just below the dry leaves is full of good stuff and great for mulch on top of the soil in pots.

Stuff from the forest is great because you can just go get it. It doesn't take any work or months of waiting like a compost pile or worm bin. It's just laying there waiting for you.

IIReignManII said:

Any tips on how to source this stuff? I need around 5-6 cubic feet of pumice or lava rock and finding the proper size of lava rock or finding pumice at all has been really difficult.

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Turface MVP is a better alternative. Super easy to find. 15 dollars for 50 lbs if I remember correctly.

Ive ordered from agron.io and build a soil at about $10 per cuft bag i believe, but its always been part of a larger order where i already had pallet shipping.
If you're in Eastern Oklahoma, i had found a place in the Fayetteville, AR area that carried pumice for (i believe) $12 a cuft. Unfortunately i don't remember who it was but it was one of only about 3 organic grow supply stores if youre close enough to make checking it out worthwhile. Unfortunately it wasn't on a website, i had to call and ask each of the stores

I can't swear to it, but i think it was either Garden IQ organics or Hog City Hydro

4ftRoots said:

Turface MVP is a better alternative. Super easy to find. 15 dollars for 50 lbs if I remember correctly.

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My local suppliers all have another version of Turface than that MVP.... But it sounds almost like it's the same stuff. When I went looking around for more info I was seeing lots of reccomendations for the Napa stuff but that's just diatomaceous earth (DE). But, turns out that Napa has another oil dry product that is the montmorillonite clay and some brands of kitty litter are the same.

I'm giving the Napa clay-based product a try this time since I couldn't find the actual MVP stuff and from my research it sounds like the type of clay is the key here. Not 100% sure but that's my current impression. The CEC seems to be fairly close among the choices.

NewGrower2011 said:

My local suppliers all have another version of Turface than that MVP.... But it sounds almost like it's the same stuff. When I went looking around for more info I was seeing lots of reccomendations for the Napa stuff but that's just diatomaceous earth (DE). But, turns out that Napa has another oil dry product that is the montmorillonite clay and some brands of kitty litter are the same.

I'm giving the Napa clay-based product a try this time since I couldn't find the actual MVP stuff and from my research it sounds like the type of clay is the key here. Not 100% sure but that's my current impression. The CEC seems to be fairly close among the choices.

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Yeah the napa oil dry is fine. Beware of oil dry quality control since it is used as a cleanup product. I bought once and it was a very soft clay product. It didn't hurt my grow, but I did have to rinse to get rid of all the dust. Rinsing might not be necessary.

Since I was using a small amount per container/batch of soil I didn't worry about the fines/dust - but there really wasn't much for the top portion of the bag I was using. That's not to say the bottom isn't horrible. No worse than the average bag of perlite I'd have to imagine.

I think Coot preferred pumice or lava rock. Id use it if I had it but I have a giant bag of perlite and I'm satidfied. I recycle my soil so lighter weight is nice too moving it around. I'm with whatever Wet says anyway.

IIReignManII said:

Any tips on how to source this stuff? I need around 5-6 cubic feet of pumice or lava rock and finding the proper size of lava rock or finding pumice at all has been really difficult.

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Got something called Pumice stone at Dollarama but it feels like plastic and make PPM go up pretty fast so I'm questioning what this product is and why we can't find the good growing supplies in Canada.

Reefstein said:

I’ve always used perlite in the past. I’ve always heard actual stone is superior to perlite since it won’t break down and turn to concrete over years of recycling the soil. I want to reuse this soil for a long time and don’t want to deal with perlite breaking down and floating to the top.

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What do you mean by turn to concrete? Perlite is made from volanic rock already