Although in not overly concerned, i would care to know what's causing some of my shade leaves to yellow off from the middle out. It is also affecting misc. Leaves from bottom to top but not every one. Its my 3rd yr of guerilla apprenticeship so i have a slight clue. Im thinking its maganese deficient, but i know without posting pics it would be hard to tell. Few more details here: Unknown bagseed. In the ground mid to early late June. Dr. Earth nutes. back in the spring i ammended the native soil with some rabbit shit, and a peat/marine based soil. Dolomite was added as well.
Mine are doing the same thing, shedding leaves from the hot weather. I give them some water in the morning and then a regular watering at night. It seems to be doing it more with leaves that are getting alot less sunlight from being closer to the main stalk of the plant and outward somewhat.
Im leaning more to a magnesium deff. I would either topdress some epsom salts or you can water it in at a teaspoon a gallon.
It looks like the start of nag deficiency but it could be from the heat or lack of light. Remember to remove leave that are over 50% damaged.
Sorry I'm new to growing mj but the rules with most plants would say leave dying leaves on the plant until they fall off. Just my .02
Once a leaf is over half dead it becomes more of a stress and hindrance than a help to the plant. Read the Oaksterdam growers course book that they use by Ed Rothensals. I believe Jorge Cervantes recommends the same thing. Those guys are the godfathers of MJ. I believe most of what they say.