Heyhey Don Brennon, great to see a thread of yours on here again
I really like your theory on the Space Monkey's, er, sensitivities haha
Given your soil must be excellent, it sounds very plausible that the change of lights incurred a sudden leap in nutritional needs - also from a microbial perspective.
I can totally understand the impulse to want to test your soil to see what you need to amend further down the line.
But what is it going to tell you, if you get a
chemical one done, really?
Even if you get one done that measures the TOTAL nutrients, not just the available ones, how are you going to know how much of that is microbial mass, or whether the set of microbes you have are well-rounded enough to be cycling those otherwise non-available nutes? Chemistry will follow in the wake of the biological activity in our soils. We need to keep reminding ourselves of that (even I do, though I've never really worked chemically, it's built into in our general mindsets!).
I think the only test that makes any sense at all on organic soils (unless you're suspecting toxic substances that may need specialized remediation) is the microbial one. When you know what the different sets of microbes are doing, what ratios they're present in, you get to see whether microbial nutrient cycling can be expected to be efficient, AND you can even determine what to amend your soil with - bacterial or fungal foods
The single minerals, they'll get those sorted by themselves. Every bit of plant matter in your compost has aaalll the nutrients in it a plant will need to grow and flourish (unless the compost was made entirely of sickly struggling plants) - else it wouldn't have grown itself to begin with! All those teensy tinsey bits of trace elements, all the NPK (if the compost was made properly and it didn't gass off right in the beginning ha) etc etc our plants could ever need...everything'S in there anyway!
But do we have the microorganisms to get the job done?
And when we did, are they still there after a few weeks? Or have extreme conditions knocked out a bunch of them, living in pots as they are, and they need to be replenished?
As you know I've been thinking about amendment alot these days. While I don't believe there's one correct answer, I'm tending to think the best way to go about amending our pot soils, especially after they've had a few runs and we have lost track of what they've been amended with (and heck, what has gotten processed of that and what not), is just a good balanced mix of bacterial and fungal foods, along with some good aeration and a wide diversity of fresh microbes for our plants to select from.
Am I oversimplifying?
Perhaps. But in the light of the newest hypothesis regarding species diversity on Earth, which etstimates the soecies somewhere in trillions - of which 3/4 are microbial - we have a loooong way to go before we can actually assess the species we have in our herd, and what they'd prefer to eat, and make sure enough of that is around for when the plant feeds up those species to get the right nutes at the right time...
As much as we'd like to think it, we're not actually in control
Hence, to provide maximum diversity for the plants to choose from, directing development of the microbial herd as they need it in every phase of their life cycle.
I feel we still have a lot to learn in managing our soils to our darling plants' satisfaction, especially in that critical stretch phase, in which clearly there is a shift in needs we need to attend to way before it happens, so the right biology will be in place to satisfy those needs and tide them over into luscious bloom.
Looking at your plants, you're definitely not far off
Cheers!