Leaves Dropping off and Yellow, Day 28 Bloom. both plants same symptom

Hello, I am using ORGANIC Living Soil Concentrate 1LB mix with 10LBS of ROOTS ORIGINAL Potting Soil in 5 Gallon Grow Bag, Water only method, Temp inside is 86 and RH 60%, this is my first time , I understand I need to give nutrient to the plants, even the Living Soil advertise that just need to water )), Pls let me know What nutrient/food I should use in this phase and how much? Thanks guys really appreciate your feedback Thanks again

Your plant is dying off due to starvation. All plants growing in pots will eventually need extra feeding, especially in flower, no matter how good the soil was to start with. Plain water may work outdoors when growing directly in the ground where the plant can search out nutrition, but in pots, nutrients run out. This is why the leaves are dying and falling off. The plant is basically cannibalizing itself..........not a good situation if you are after prime buds.

My guess would be your soil has been depleted of its nutrients and you need to do a little top dressing. The other thing is your canopy is dense and this could be a natural defoliation. This can happen when the lower leaves do not get enough light so the plant will drop the old to focus on the new. But considering this will happen usually to only a few leaves here and there. I would say you need to add some more food. Happy Growing

This looks like an iron deficiency to me... yellowing starts in the middle of the leaf and spreads out towards the tips... Good luck!