@Gee64 here's an interesting discussion on soil amendments. He doesn't like either greensand or kelp but interesting and guy seems to know his stuff.
This guy is a soup grower. He uses organic componds in hydroponic applications, so for starters you can't compare my style to his but....
Arsenic doesn't make the list. Not even as a trace element. If he finds arsenic in his liquid kelp he needs to address the manufacturing process.
He also never mentioned myco once.
His style is to feed the plants himself. I trust myco and the microbes to do a better job than me. I know I'm not as smart as Mother Nature. No your limit, play within it
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Thats not to say his system doesn't work, I'm sure it works really well.... If you purchase whatever line he is influencing and/or selling.
Synthetics would be easier. Probably cheaper too. He says "fertigate".
He talks alot about addressing deficiencies. I prefer to avoid them.
As for greensand, it would mess him up bigtime as it constantly trickles K for years, like it's supposed to.
Kelp does contain a relatively high amount of sodium but far less than any synthetic system and I have never had a sodium problem. It's an electrolyte. It's potassiums backup. Theres a reason nature creates them together.Just keep it in balance.
Kelp and greensand are my staples and I've never had a K deficiency. Follow the brix, not the capitalists.
Did he mention brix? He talks a lot about photosynthesis, but if you have brix you have photosynthesis. Foliars can give you high brix but good soil gives you much higher brix.
But again, I'm sure if you are true to his product you will do fine. When you buy something thats all you can really ask for.
If it makes for fun growing I'm all for it, it should be fun.
When he says things like "It takes 3-4 weeks for 100% of it to be made available" cooking your mix IS that 3 to 4 weeks. Embrace that, don't look at it as bad.
Thats also why you do today for what you need in 2 weeks.
But it is comparing 2 different styles so as long as you realize his philosophy doesn't apply to LOS your good.
If you do end up with a deficiency, a lot of what he says will rescue the plant.