What could be the yellowing problem ? starting fro...

N K Ca Mg could be P deficiency

Hello mate, i think you have an issue with your pH, looking your diary i see that your pH solution is 7, it's too high! It should be around 6.2-6.5. This could caused a problem with the immobile nutrients that show signs of defiency/excess starting on the newer leaves and on the older leaves. Your yellowing could be a defiency of Sulfur or Iron but i say again cuased by wrong pH. Good luck and happy harvest!

Does the issue seem to progress more when it's time to water? I had some Autos in 3 gallon pots and 1 in 2 gallon that the leaves started looking like yours in early flower and if I didn't fully saturate the pot or if I let it dry out then the issue would start coming back. My issue was root related and I'll be using 5 gallon pots next time. Just something to keep in mind if ph change doesn't help.

Hey, I would recommend lowering the pH of the water to 6.2. Do it gradually—reduce the pH by a maximum of 0.2 per watering. Dropping it too quickly might shock the plant. Google :nutrient absorption cannabis ph related for more Information. Your Plant is currently low on nitrogen i guess. Good luck!

Hi, Initially, it would be advisable to test the pH level of the substrate to ensure it falls within the optimal range of 6 to 7 pH units. Since you have limited fertilization, which is a valuable step to avoid over-fertilization, it would be beneficial to assess whether the plant is lacking any specific nutrients. Considering that the plant is currently flowering, you might consider supplementing it with a fertilizer that has a higher phosphorus content (such as a "Bloom" type fertilizer). Phosphorus is an essential nutrient for the flowering process, as it promotes the formation of flower buds and extends the duration of flowering. Good luck buddy.

Diary says PH 7.0, I'd have aimed more for ph 6.0-6.5, the damage you see now is from something done weeks ago. Could be nute lockout through ph being a bit to high.

Why there don't worry to much your almost ti the point it's really hard to completely mess up the buds I think you either have a watering problem or a nutrients problem. You don't have much detail on either in diary. Just think if you started adding something new recently or have you increased doseing recently or have you given 0 nutrients lately. Trust yourself just know it takes time to recover don't keep changing things over and over everyday thinking tomorrow it will be fixed sometimes when your this far into the grow and you have leaves turn weird colors for any reason lots of times they never go back to 100