Underfeeding?

It could be a few things. Bottom leaves yellow and die off due to watering problems, underfeeding the plant, or from not getting enough light. Since you're in flower, it could be wanting more nutrients. So, bumping up the amount that you feed them by a little bit could help. Check and see if the leaves are getting enough light. If they are, check the pH of your water and run-off from the pot, just to be sure. After you know that pH isn't the problem, diagnose what deficiency/deficiencies might be showing in the leaves and address them. Here's a link on identifying deficiencies and toxicities: https://dutch-passion.com/en/blog/a-visual-guide-to-cannabis-deficiencies-n987 Here's a link on why leaves yellow and drop: https://www.royalqueenseeds.com/us/blog-yellow-cannabis-leaves-n523 If you're new here, please select the answer that helped you out the most by clicking on the "answer" button underneath what the person said. If you have any questions, feel free to message me on here. You can pull up your messages tab by clicking on the little airplane in a bubble. It's located on the bottom-right of your screen. I hope this helps!