Lava Rock Replacement?

In my area it is really hard to find a cheap source for Lava Rock, and was wondering what exactly are the pros of Lava Rock and could it be substituted out with for example BioChar? I have gotten some TGA gear in and moving to slightly bigger pots and want to start my soil over from scratch so any enlightenment would be great.

404NotFound said:

In my area it is really hard to find a cheap source for Lava Rock, and was wondering what exactly are the pros of Lava Rock and could it be substituted out with for example BioChar? I have gotten some TGA gear in and moving to slightly bigger pots and want to start my soil over from scratch so any enlightenment would be great.

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Everybody is caught up on the whole lava rock thing. The whole point of the old thread was lava rock/pumice was locally available and that's why they used it. Same with the Basalt rock dust, it was local to them. Granite has the almost the same properties and people who lived in New Hampshire ("The Granite State") were having Basalt shipped across the country for no reason.

Use what ever is cheap and you can get locally. Bio-char is good to add, pea gravel is nice and cheap, rice hulls can be bought at home brew stores for next to nothing. Take a trip to a landscaping supply yard and look at the various rocks they have and just go with the size you prefer.

RandomHero8913 said:

Everybody is caught up on the whole lava rock thing. The whole point of the old thread was lava rock/pumice was locally available and that's why they used it. Same with the Basalt rock dust, it was local to them. Granite has the almost the same properties and people who lived in New Hampshire ("The Granite State") were having Basalt shipped across the country for no reason.

Use what ever is cheap and you can get locally. Bio-char is good to add, pea gravel is nice and cheap, rice hulls can be bought at home brew stores for next to nothing. Take a trip to a landscaping supply yard and look at the various rocks they have and just go with the size you prefer.

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So there’s really no importance of the lava rock per say, with the exception of its availability to your area and aeration properties which can also be found in biochar as well.

404NotFound said:

In my area it is really hard to find a cheap source for Lava Rock, and was wondering what exactly are the pros of Lava Rock and could it be substituted out with for example BioChar? I have gotten some TGA gear in and moving to slightly bigger pots and want to start my soil over from scratch so any enlightenment would be great.

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You said it-
Bio Char.

This is what I'll be replacing lava rock with soon as I have bad discs in my lower back and the pots are way heavier with lava rock..The porosity of the rocks have convinced me that they do indeed harbor more bacteria and allow them to thrive at a better rate. My plants did awesome when I started combing lava rock with perlite in my mixes as opposed to just using perlite.

I'd get some oak charcoal put it in a steel drum and char it just enough to add some porosity leaving the shape of the coal in tact but make sure it's thoroughly charred inside and out.

Afterward put it in a Nitrogen source such as an Alfalfa tea and let it sit for a couple of weeks.
Pull it out and it's ready to go into the soil..

MR is the only one who mentioned the industry standard, lightest and cheapest solution, that being perlite.

I don't have bad discs per se, but a really healthy dose of RA in my spine Rocks of any sorts was just a non starter in my mixes.

I start with ~40% of perlite, but biochar along with pine bark fines are also added. The bark fines do become humus in a couple of years and are not considered a forever aeration amendment like the perlite.

Locally, a 4cf bag of horticultural grade perlite is $17 ($16 a year ago). The weight of 4cf is 18lbs, if you feel like comparing prices and weights.

For the biochar, I have a smoker and just use the shake from the bottom of the lump charcoal bag.

Read in several sources that biochar shouldn't exceed 20% of the mix and ~10% is better. Something you may want to research before using it as a sole aeration amendment. Don't remember exactly why any longer, but mine is usually well under 10% so I didn't persue it.

Wetdog said:

MR is the only one who mentioned the industry standard, lightest and cheapest solution, that being perlite.


Read in several sources that biochar shouldn't exceed 20% of the mix and ~10% is better. Something you may want to research before using it as a sole aeration amendment. Don't remember exactly why any longer, but mine is usually well under 10% so I didn't persue it.

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I'm trying to understand why perlite gets a bad rep? It's recycled..Probably hydrocarbons. I noticed people steering clear of certain amendments and even having things shipped when they can get something of the same elemental value up the street..

..Alfalfa/Neem
Lime/Oyster Shell flour
Bone meal/Crab meal

You bring up a good point in your last paragraph. Something I failed to point out. I would never (personally) exceed 8-10% bio char in my mixes as bio char is very Alkaline in nature. I'd personally like it around 5% of the aeration percentage. This doesn't seem like a lot to someone who hasn't observed what 5% chunky bio char can do

Great carbon builder.

MistaRasta said:

I'm trying to understand why perlite gets a bad rep? It's recycled..Probably hydrocarbons. I noticed people steering clear of certain amendments and even having things shipped when they can get something of the same elemental value up the street..

..Alfalfa/Neem
Lime/Oyster Shell flour
Bone meal/Crab meal

You bring up a good point in your last paragraph. Something I failed to point out. I would never (personally) exceed 8-10% bio char in my mixes as bio char is very Alkaline in nature. I'd personally like it around 5% of the aeration percentage. This doesn't seem like a lot to someone who hasn't observed what 5% chunky bio char can do

Great carbon builder.

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Perlite gets a bad rap because it's used in shitty pre-made soils that perform poorly over time as far as drainage goes. I stopped buying pre-made a long time ago but all the stuff I've seen has used small perlite as opposed to the big chunky stuff which causes it to float to the top. This may just be from poor watering habits though.

RandomHero8913 said:

Perlite gets a bad rap because it's used in shitty pre-made soils that perform poorly over time as far as drainage goes. I stopped buying pre-made a long time ago but all the stuff I've seen has used small perlite as opposed to the big chunky stuff which causes it to float to the top. This may just be from poor watering habits though.

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I've never had perlite float to the top of my pots and I've been using it for years.

so you're probably right, poor watering habits..

Works great, easy to remove, clean and reuse after harvest. Smallert stones inside the small net pot

MistaRasta said:

I'm trying to understand why perlite gets a bad rep? It's recycled..Probably hydrocarbons. I noticed people steering clear of certain amendments and even having things shipped when they can get something of the same elemental value up the street..

..Alfalfa/Neem
Lime/Oyster Shell flour
Bone meal/Crab meal

You bring up a good point in your last paragraph. Something I failed to point out. I would never (personally) exceed 8-10% bio char in my mixes as bio char is very Alkaline in nature. I'd personally like it around 5% of the aeration percentage. This doesn't seem like a lot to someone who hasn't observed what 5% chunky bio char can do

Great carbon builder.

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Think back. We've both been here for years and have seen it happen. The main influence being Coot/Lumperdawgz and the whole *new* no till method. People, especially the inexperienced, took everything at face value despite experience and observation to the contrary because Coot said so. Most of it works very well. Some, not so much.

Most of these 'designer' amendments are off the shelf items on the west coast, especially in the PNW and would naturally get used. I would also. But the stuff 'up the street' never got mentioned and it was felt that one must have oyster shell flour instead of Ag lime, fish bone meal/crab meal instead of steamed bone meal and so on.

The cost in shipping was enormous, but essential for no till because Coot said so. Never mind that the 'up the street' stuff worked just as well for way cheaper. Neem was an exception since there is nothing else much like it.

I still love neem cake/meal, but have gotten much less generous in its use. Another gardener summed it up quite well, "A large bag of kelp and a small bag of neem". The alfalfa and soy meals are seeing much more use again.

Got into huge arguments over at GC when I called BS on Coot's claim that perlite would float to the surface even from the bottom of a huge container. From experience with my own nursery I knew this wasn't true. Others, with experience, like yourself, agreed. The ones with no actual growing experience were the ones insisting this must be so, since you know who stated it. Ignorance can get really tiresome. LOL

Perlite is an inert mineral with a water content that, when heated, makes like a rice krispy. That's pretty much it, no recycling or hydrocarbons involved. No, it doesn't cause cancer, but the dust IS an irritant as is the dust in a grain silo.

It is also used as insulation in CBS construction and I'm not 100% on this, but more than likely its first use before the nursery industry discovered it for aeration purposes. Vermiculite is used similary for insulation, but I don't use it in my mixes because it retains too much water. Seems to work ok in some seed starting mixes though.

Wetdog said:

Think back. We've both been here for years and have seen it happen. The main influence being Coot/Lumperdawgz and the whole *new* no till method. People, especially the inexperienced, took everything at face value despite experience and observation to the contrary because Coot said so. Most of it works very well. Some, not so much.

Most of these 'designer' amendments are off the shelf items on the west coast, especially in the PNW and would naturally get used. I would also. But the stuff 'up the street' never got mentioned and it was felt that one must have oyster shell flour instead of Ag lime, fish bone meal/crab meal instead of steamed bone meal and so on.

The cost in shipping was enormous, but essential for no till because Coot said so. Never mind that the 'up the street' stuff worked just as well for way cheaper. Neem was an exception since there is nothing else much like it.

I still love neem cake/meal, but have gotten much less generous in its use. Another gardener summed it up quite well, "A large bag of kelp and a small bag of neem". The alfalfa and soy meals are seeing much more use again.

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Lol, shipping organic amendments..
I agree on the neem though. Luckily you don't need much, at all.

The 'no till' craze received a popular following. It still does because it's more like a cult. All the people who follow the no till methods all have the same exact procedure and way of doing things.

I tried the mix for a couple of rounds to see what it was all about..

The veg growth is great, vigorous plants that just continue to grow like a vine. Flower is a whole different story imo. Way too much N and way too little P for any serious oil/terpene production. The taste of my plants wasn't there, they didn't stink out the entire room, and they were a lot more harsh.

They honestly reminded me of very well grown and flushed hydro buds.. just kind of bland all around..

Needless to say I went right back to Rols as my buds are just all around better..and other than transplants it's indefinitely an easier system to keep up with over time.

A cult like following for sure and I guess it sounds cool to say (or type). It sure gets mentioned enough.

In the new "No - Till Revisited" thread started by BlueJay (MOFO), the new recipe is different in what it lacks from the first No Till thread (Locked now, but still there). This is mostly from memory, since it's been a bit since I've looked at it.

Aeration: Pretty much, either Lava Rock or Pumice is it. Perlite isn't even mentioned, but rice hulls may be (a real cluster fuck as aeration), but I'm not sure.
Lime: No mention at all. At least the first recipe had Oyster shell flour mentioned
P source: Again, no mention. The first had Fish bone meal at least.

Then, the acolytes started having problems. Couldn't understand why since they had followed the recipe to a T. One guy had even weighed out his amendments to two decimal points.LOL That's dedication!

But, when offered real life solutions like, perhaps some perlite or at least not just dumping a bag of BBQ lava rocks into the mix and calling it good, or, adding some sort of liming agent to correct a too low pH (Hint, basalt does NOT replace Ag lime), or, adding a P source like bone meal, fish bone meal or even high P guano, the usual reply went "So and so said it wasn't needed or necessary and I'm not using it". Or something to that effect.

Others, like yourself, who saw what was lacking and the results from that lack, just went ahead and added what was missing. The others may or may not figure it out on their own.

Like I've said before, my no tills are just those pots too big to move by hand and I try top dressing as long as possible. Even then, after a couple of seasons it's time to get the wheelbarrow, empty them and do a complete overhaul of the mix. If it's really spent, it gets dumped on my soil gardens that just get worked by hand. Not by design, the location sorta rules out any power equipment.