Deficiency

excess of water can lead in to deficiencies it will no help your roots too, you spray them as we can see in those pics, my advice will be let the soil dry and dont spray them when the soil is that wet.

Something seems like its off in the medium be is PH or nutrients, They also looked fine the week previous was their anything added in that was new? that might be the culprit. I agree it could be potassium and stop spaying the leaves. and its likely has to much N. With the addition of that gusher product at 0-0-26 it seems like it should not be K, and that might just be old damage that will stop progressing. Also that product is said for oil building crops. I don't think cannabis is one of them but I could be wrong. We grow it out for flowers not the seeds or the oil in the seeds. Review whatever else you are feeding them and double check the strength of the solution with a EC pen. It might be getting to much. Soil grows should be fed once a week with liquid nutrients and once every 3-4 weeks with dry amendments. the rest of the time just water with w/e additives you add in like PH up/down. Good Luck!

It looks like there could be a multitude of issues but my guess is due to the dark looking leaves that you’re over feeding your plant and/or not watering correctly at the same time. Remember, when you water you plant you want to saturate the entire media throughly over a period of a few minutes and water enough to have roughly 10-20% of water come out the bottom. This will help eliminate the build up of nutrients in your medium. I suggest on you give it straight pH balanced water your next feeding and have roughly 20% flush out the bottom. Also, it looks like you leaves are wet, if you are feeding a foiler spray, stop immediately. There is no need right now to spray your leaves unless you are in such dry climates that it will require extra humidity in the grow environment. I hope this helps.

looks more overfed and some major imbalances played out over long period of time. A smorgasborg of symptims... Impossible to be anythign close to certain from these pictures. if foliar spraying nutes, stop that... learn how to feed them properly thorugh the roots. that's how the plant was designed to fucntion. Sure a foliar spray can be useful in an extreme case and immediately provide certain nutes to a specific location through the stomata (which are on the bottom of the leaf, not the top), but better to just avoid that catastrophe and simply feed it properly and never have to do a nutrient foliar spray. Only some nutes can traverse the stomata, too. This is something that makes peopel feel like they are doing somthing useful, but really just creates additional risks of problems for a behaviour that is not value-added or shouldn't be if fertilizing properly. You may have some sort of lockout due to one or more nutes being fed at a too high of a concentration. Or, a pH issue, because this is usually what is behind what looks to be overlapping, multiple symptoms. soil grow.. so it really depends on how much was in the soil and what you added sicne.. shit-ton of unknowns... even if you kept track of what you've added each time you fertilzied. you'll guess better than someone here in these answers with that knowledge. some leaves look dark and glossy which can be a sign of too much N... too dark can also be caused by a lot of potential toxicities, for that matter. Mg and Ca do it without the glossiness. Possibly a k-deficience witht he burning around serated tips as well as accompanied by interveinal chlprosis. the tip burn on last pic could be too much p or too much S The fact all of these are coinciding, like i said, hints at a pH or nute lockout.. or just an imbalanced fertilziation program with several parts being off. react to symptoms sooner.. or at least track them... how they progress, where they progress is insight to the cause of the problem. Leaf symptoms are not 1:1 discrete with a specific cause. you need more data to eliminate the multiple potential causes of the same visible symptom in many cases.