Hey BK, how are you? Thanks. This was done using the Trim Bin (this is an actual product, available on the Zon) and the screen it comes with, which I believe is a 150. So far I haven't gotten the finer screen to go under this one, but they make them. It's one of my favorite tools. I consider it poor man's (and lazy man's) way to get kief. Hell, I could turn it into hash with wax paper and an iron. I didn't know that about bubble hash, which essentially begins just like this stuff - as pure kief, correct? I am 100% certain the bubble/dry ice extraction method is going to net more kief than I get with the tray. But I guess the difference is the way I do it the kief is dry dust immediately, or a day or two later. I have never tried to do anything with it except top bowls or bongs, and roll it into joints. And collect it. Lol. I know I leave a lot of kief in the bank this way, but once I get to the point where a pass is showing the slightest green, that trim is done for kiefing and goes into bins for butter. Still has plenty of oomph left for butter this way.
Roots in a soil grow. Hmm. Off the top of my head, honestly, my answer would be microbes. One way or another.
But if you want an actual product from a nute line, I have had good success with Fox Farms Root Drench. It seems to maintain root health well if the tops of the plants are any indication.
Love the if you can only pick one type questions, lol. If you want one product that will help your plants every time, in every scenario, no matter what the strain, without fail, 100% guaranteed to help and make your plants healthier, stronger, and significantly more capable of transferring nutes from root to leaf - that is the all-important MSA (mono-silicic acid) at some high (40s) percentage. If I only get one I'll take that.
Hope that helps!