I’m looking for a way to make soil for my seedlings. i want them to grow nice roots before i replant them. and i want to use lava rocks in my soil to help oxygen move throughout the roots. im not sure if this will work and need some guidance as to what i should mix with the lava rocks, i have coco coir but i think that only a little can be used because of acidicness? for nutrients i was thinking i could put gypsum and brown rice flower in? any help will be greatly appreciated, note that i will not just order expesive soil off amazon/internet because in my opinion that’s a waste of money.
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I think you need to look In the FAQ section and do some reading first . Maybe after that ask your questions . Lots of people who will help you on this site . 
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I would suggest you use a real soilless mix and real nutrients.
If you have tons of experience you can start screwing around with little details.
I use promix and add 20% perlite for aeration. I estimate I spend…$40 on soil and nutes per grow.
It’s a small price to pay.
You could use your own pee for nitrogen - but I wouldn’t.
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would i be able to use lava rocks with soiless mix? i want the roots to have oxygen above everything. also lava rocks would allow me to use less soil and such. or do you think i should scrap the idea and plant them from someone elses instructions?
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I suppose you could (I’m assuming they are the expanded clay type) and it would likely increase aeration.
If your goal is to save a bit of money, it won’t. Those rocks are not cheap.
Perlite does the same thing and is cheap when bought in bulk. I got 4 cubic feet for $35. Just don’t buy the small bags. Those add up fast.
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Don’t reinvent the wheel. There is a reason that perlite is the most commonly-used supplement for soil and soilless mixes for aeration. It’s cheap, it’s effective, and it’s available everywhere. The only reason why anyone should be using lava rocks is as an alternative to hydroton in hydroponic setups.
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I’ve used lava rocks. They work great for aeration. Perlite is better because you can move the pots. A 5 gallon bucket with soil and lava rocks as aeration will weight twice as much as a perlite and soil pot. The difference in quality is not worth having heavy pots. I grow in 30 gallon pots with perlite and can barely pickup the pots. With lava rocks as aeration in 30 gallon pots weigh slightly less than a Volkswagen Beetle.
Where would I think about lava rocks?
Permanent beds you have no plan on moving anytime soon. Lava rocks are typically used in No till beds that are outdoors or not going to be moved. Something like 50+ gallon pots on rolling platforms in a Kiddie pool in a basement is how I would do lava indoors.
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If you plan on using your own urine for ferts, you’ll need to dilute it by 10 to 1. There is entirely too much nitrogen in urine to use straight. Urine contains an average NPK of 11g N - 1g P - 2g K per litre.
You can use any soilless medium you want and add volcanic rock to it and it’ll work just fine. If you’re only adding lava rock to increase soil aeration and decrease soil compaction, perlite or vermiculite work to accomplish the same thing and weigh a whole lot less than lava rock.
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@Chemsick A living soil has three parts.
The base is your coco, or peat or whatever.
The aeration would be the lava rock, but like everyone else is saying, bulk perlite and vermiculite are cheap and effective.
Last is nutrition, and is really the only part that gets customized. Eggshells, Oystershell Flour, Gypsum, Basalt, Greensand, Bone Meal, Blood Meal, Guano, Manure, Kelp, Alfalfa, Crustacean Meal, compost, Vermicompost, Black leaf mold. The list is effectively endless. If you want one step and done, check out espoma hollytone. It’s mostly chickens and rock dusts.
I was kidding, a little. Nitrogen is everywhere, there’s no need to figure out a way to use your pee, unless you really really want to.
There may be Good reasons for doing such things, but you should know what they are before doing them.
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3- 7 LB bags fit a 5 gallon bucket leaving plenty of room to plop a vegged plant into it.
I used it in a KFB set up back in 03, a hydro set up.
This one is started in a mix of perlite/vermiculite/LR. I had used soil to get the plants started in, but washing it off the root mass was time consuming. So I made this mix up, then pulled them, and plopped them into an inner bucket filled with LR, for some more veg time then flip at the nips.
I did run one bucket with soil/LR, I did not see any advantage
to running the LR over/ a bucket with coco coir/coco coir husks/perlite mix. Very light weight, and it will build a killer root mass also.
Just my $.02
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Great reply webeblzr! Nice plants, too, by the way!
That looks to be pretty much the same idea as growing Hempy style, but using lava rock instead of perlite/vermiculite.
Plants can grow an amazing amount of roots using this method. It’s one of the easiest methods in which to grow great cannabis.
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Hey Ya Desert Grown,
Yeah back when I was just gathering up some skills, learning as many different mediums as I could.
I wanted to be a soiler, but my area is subterranean, and I was, er am getting old, so carrying hundreds of pounds of soil down the steps, then back up the stairs, just was not an option for me.
Then Krusty came around and showed us his concept and being a hopeless tinkering fool, I copied every step of his I could, and cheated as closely as possible when I had to.
I loved that system, ran it for 2 years, until I could not stand the constant THUMPING of the Thomas air pump that ran 27/7 365. It was the excited frothing of the inner bucket with 1/4" soaker hose, looped around in there. You could see nutrient vapor wisps, rising up through the 21 pounds of LR!!
And, the tiniest seedlings would go crazy for that vapor.
I just wanted to show the OP, LR will work as a medium, but as others have stated, a perlite medium, or adding coco husks will give your benifiicial orgasmisms a place to live and thrive.
Plus being dirt cheap, it is hard not to use them over LR, IMHO.
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Beautiful plants man. I can see where in your circumstance it would work excellent.
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