Get the local perlite, a 4cf bag if you can. AFA variety it should say 'horticural grade', or, just Perlite. They are the same stuff. "Chunky" is just a gimmick and actually works less well, besides costing more.
Here is my beef with pumice, lava rock and the like and inexperienced growers. Especially those following any sort of recipe.
THE SAME VOLUME OF LAVA ROCK OR PUMICE PROVIDES MUCH LESS AERATION THAN AN EQUAL VOLUME OF PERLITE.
The rocks being larger have way less surface area than the much smaller perlite and provide less air spaces and a more dense mix. If you were following a recipe that called for, say, 5 gallons of aeration, 5 gallons of perlite should be well aerated, but using 5 gallons of say lava rock would just give you a too dense and poor draining mix. Of course you could use more to correct this, that is where the experience and "eyeballing" comes into play. But, just measuring out like you're baking a cake aren't going to give you the results desired.
I see this happen over and over and over again, usually with yellow leaves (at the least), and "I followed the recipe exactly, *EXCEPT* I substituted X for Y, because some poster said to". Usually, this is either the Aeration amendment or, the liming agent and the substituted material being unsuitable for the task. Using rock dust for a liming agent seems to be popular for some reason.
Get the perlite and the D-Lime and have known items to work with and that are known to work. Once you have a basic, REPEATABLE mix that works well, THEN you can experiment with different things, having a base line to work from.
Wet
I do see your point, and considering assembling a "virgin" soil mix is challenging in it's own regard, especially if no sources of good humus/microbial life is available.
As far as the dolomite lime, my only complaint/concern with that is the magnesium involved, more specifically the ratio of it, it's like 2/1 ratio of calcium to mag, In the VERY high organic ratios of the soil it's just a lil much, especially in a soil that isn't predicated on peat (but I acknowledge that many do indeed use lots of peatmoss) sometimes that can create issues over time, especially those that like to use black strap molasses and such.
I'd probably choose calcitic lime over dolomite, but I really just rely on the composting procedure and microbes to keep the soil a nice neutral, to verrrrry slightly acidic ph.
If I was using a peat based mix i'd be probably using some sort of lime.
BUT, I hardly have any peat in my soil, mostly compost which is always a neutral ph anyways, couple that with the small liming capabilities of oyster flour, crabshell, shrimpmeal, manure, and biochar.. (often people forget the natural liming ability of simple composted steer manure)
but again you brought up a really good and overlooked point, what you and I do without thinking is sometime taken for granted.
Now don't take that as me being arrogant, ask me to ppm, ph or whatever-the-fuck-it-is-hydro-guys-are-doing-nowadays, and i'll look at you with a confused look. Same can be said of a lot of subjects.
but I can assemble soil like a mofo
But i'd say 99% of the population would acquire that knowledge over the 25 yrs that I've been growing, so I better know how to make soil or I should kick myself in my own nuts, or find a different hobby.
But it's not easy, it just comes over the course of, as you said, fuckups.
The entire reason why I am here on this forum is to just show people how simple it can be once you have a good foundation, active humus.
That's the secret, active, fresh, loaded with microbial life, super high CEC, always conducive ph, HUMUS and perfect in retaining and releasing organic nutrients over the lifespan of flowering cannabis.
Take away my compost and i'm just an above-average grower, I freely admit that.
but armed with compost?
well, anybody can grow amazing plants.
Not to mention that it's great for landfills as well, all those leaves aren't getting buried or composted improperly
