Yeah, I was shocked too. But remember, its mostly for removing salts. Its often used in an agricultural environment to eliminate the salt build up they face annually.
Langbeinite is superior to gypsum for dissolving salt builups, however Gypsum is often cheaper, which really reduces expenses when we're talking such large scale like agricultural fields/farms. Depending on where you live, gypsum can even be found as a waste product of various businesses dealing in sheetrock and the like.
https://www.researchgate.net/publication/324844679_Gypsum_langbeinite_sulfur_and_compost_for_reclamation_of_drastically_disturbed_calcareous_saline-sodic_soils
You might like that article. I've linked it before in the past, but its a very informative read for anyone curious.
The tl;dr of this experiment report is seeing what does a better job of removing salts (CaCO3 included) from soils; Gypsum, Elemental Sulfur, or Langbeinite. The results of the experiment proved that Langbeinite was superior, followed by Gypsum, then Elemental Sulfur.
This makes sense, because Elemental Sulfur needs microbes to "oxidate" the sulfur; converting the S into SO4 (Sulfate). It is the SO4 specifically that breaks the CaCO3 apart, not S.
You'll note that both Langbeinite and Gypsum are sulfates (Magnesium Sulfate Potash and Calcium Sulfate respectively), having SO4 already in their chemical formulas, whereas Elemental Sulfur is just Sulfur, making it useless when compared to gypsum and Langbeinite which act immediately instead of over months of time.
The article even points out how, despite Langbeinite's 0-0-22 NPK, the soil treated with Langbeinite had the same amount of K as the soils treated with Gypsum and Elemental Sulfur, heavily implying that the plants made full use of the large amount of K in Langbeinite with zero ill effects.
All the best!
Diluting the soil with another medium will definitely help you. However, the issue is that Roots Organic soil will have more Dolomite Lime in it, so this won't help too much.
In your shoes, I'd be looking for a soil that has
zero Lime in it. Or, I'd build my own soil mix, using nothing but peat/aeration/compost. I would then transplant into the peat/compost/aeration custom soil I made, proceed to water and top dress as normal, and wait a week or two to observe the results. Ideally, that would solve the issue, but its always best to wait a week or two to confirm the issue has been dealt with.
I'd much rather prolong veg by 2-4 weeks, rather than trigger 12/12 too early, and cut my yields by 50-75% because I did not solve the issue. Rest assured, you can in fact still get good smoke with these issues. However, your yields will be cut severely. A plant that normally yields 4oz, but experiences these issues, will yield 1-1.5oz at best. Trust me, I've had the pleasure of learning this one the hard way.
Even if the 4-4-4 has Langbeinite in it, it likely is not a sufficient amount of Langbeinite to eliminate salt/CaCO3 build up in one's soil. Though, that is assuming salt build up is the issue here. Its a lot like fixing a car or a computer, you want to fix one thing at a time, then observe the results. Changing multiple variables at once will make it difficult for one to pinpoint what the exact issue was, leaving one just as lost as they were when they started.
Issue here could be salt build up, excess Calcium, or excess CaCO3. Unfortunately, the answer is different for pretty much every grower. This is because every grower not only has different soil recipes, but different sources of water (hard/soft/well/RO/etc.), different organic inputs, and different sources of compost.
For my issue, even using pure peat moss with no lime (3.5 pH) was still not enough with my water. My water would still build up CaCO3 salts in the medium after a while, causing that magic 7.5 pH number that lets us growers know what that we have this issue in the first place. I have to buy Calcium filters on eBay just to make my water usable. I know when its time to replace my filter because I start seeing Mg deficiencies immediately, followed by K deficiencies, which means my Ca filter isn't doing its job and the excess Ca build up is now resulting in K and Mg being locked out. P will come next.
Its also worth noting; I
never experience this issue with plants in the ground, only in plants that are potted. Why? Because when plants are in the ground, the salts are free to flow below the root zone. The salts still exist and buildup, but it is far below your root zone, resulting in zero issues.
In fabric pots, the salts have nowhere to runoff to, so they get stuck in your soil because they cannot flow outside of the root zone like in the ground.
My best guess is that the issues you're having is related to the excess CaCO3 from the extra Lime that was put into the soil. But without being there, it is only a guess. But now you have plenty of information that will allow you to effectively troubleshoot this issue.
I'm sure you'll be able to fix this issue with ease, its just a matter of finding out what the specific issue is. That said, I would highly recommend waiting until the issue has been troubleshooted prior to initiating 12/12. The thing with these issues is that one will often think the problem has been dealt with, only for it to arise 1-2 weeks later. This is the last thing one wants once they're in flower.
You can reverse nearly anything in veg, but you're fucked in flower.
Hope that helps, all the best.
