several small signs of something wrong, pics provided

[Elisabeth65]

Your RH isn't nearly as important as temps. If concerned, an occational mist using ph'd water is fine. I live in the desert, where ambient RH is around 9%, and have found they prefer the lower RH. Especially when flowering.
Do you have adequate ventilation and air circulation?

Yeah, I got 2 small computer fans blowing air in, and one duct-fan with carbon filter pumping air out, maintaining underpressure in the closet. I am however getting a cool tube soon, I'd like to get my setup to run even less noisy.

Epsom salts every nutrient day? The dingy yellowing is likely a result of salt build-up throwing off your ph, and creating a toxic soil enviornment. (early lockout) A good flush will help release the salts, but wait till the soil drys, or you will risk root rot.
Official Epsom Salts Not Miracle Cure Thread

Yeah, I've used lots of epsom salts recently. I haven't used them on every watering tho, only the last two. Last time I watered the plants I did a PH test, and it came out at about 6,8. Isn't that quite optimal for soil-grown cannabis?
A salt buildup in the soil sounds likely indeed, gonna ease down on the epsom salts. Definitely gonna flush the soil too, thanks

Not likely if it's the only plant showing these signs. What's your water and runoff ph? Are you using tap water?
Looks like you've been adding stuff to correct deficiencies, and have overwatered as a result.

runoff pH: 6.7-.6.8. It's been stable throughout the entire growth period (measured 3 times).
I use tap water, which is a bit hard I guess, with a pH of 7,5-7.8. This pH drops to about 7 when I add nutrients.
Unfortunately, I don't have a ppm meter. Would love to know the EC of my tap water.
I don't think I've overwatered either, my soil dries up quickly, as I have lots of perlite and lots of holes in the pot (both under and on the sides of the pot). I water when I feel no moisture 3-4 inches down with my finger.

Looks like leaf-irritation from another plant or leaf, to me. (the fans can blow the leaves back-n-forth across another leaf, causing those spots)

That made sense, didn't know about that. The plants have had a lot of wind blown at them by the table fan, maybe too much. The angle of the fan has been shifted so that they now receive less direct air ventilation.

Or magnesium toxicity.

Are the symptoms of magnesium toxicity=magnesium deficiency?
I thought the signs of magnesium toxicity were lockout of calsium, potassium and phosphorous, with deficiency-symptoms of those nutrients.

Thanks for the help everyone:thumbsup: I'm gonna go ahead and flush the plants once they dry up again. I'll post back here later with the results :] peace :stoned: