Why are leaves yellow?

Thanks a lot for your suggestions. As well as asking here I ask a friend of mine, an experienced cannabis grower, for advice. She tells me that I should transplant the weed to a larger pot to make a sufficient room and nutrition for the roots. Now there are three possible reasons here; 1) too small pot size 2) deficit of nutrient, lack of magnesium 3) excess of nutrient, nitrogen lockout 4) excess of water I confess that I do not use any nutrient at the moment, thus it is not likely to be excess of nutrient. Possible solutions can be a) transplant to a larger pot [for 1) and maybe 2)] b) stop watering [for 4)] c) feed nutrients [for 2)] Now I try b), and if she is still in bad health I would like to try a), then c). If you have any idea please tell me that. Every single advice is helpful for me. Marinik

I I think it could be MG deficiency which is magnesium deficiency there’s a great product from General hydroponics called Cali Magic it’s a great source of calcium and magnesium My other diagnosis would be overwatering and your pH being off which can block out nitrogen to your plant you can also try Epsom salts for a source ofMagnesium sulfate

hi there Marinik, i dont have any information about your feeds, water, temps etc, but it looks like you have Nitrogen lockout from too much nutrient no a deficit. That's because i'm guessing you're already feeding so it's not a deficiency . So what you need to do is cut the nutrients for some time by watering with plain water only , hopefully it will bounce back... try to water with plain water until you see some run off , then measure the amount of water you used, then add 20% more water after that. that's a flush ! You probably need to flush to clean the medium from the extra nutrients. Hope this helps ! 🚀