Jack Herer Autoflower

This is my first grow and I'm looking for some feedback. The plant has been on an 18/6 lighting schedule with around 350 watts of LED for an indoor grow. It's about two weeks into flowering, and the buds are looking good, but i'm noticing an increase in the amount of leaves that are getting brown spots, then ultimately wilting, mostly on the bottom half. However, even the large fan leaves around the Kola are starting to show brown tips. I'm growing in a 5 gallon bucket, with Kind soil in the bottom 1/3 of the bucket, and miracle grow 'Nature's Care' in the top 2/3 of bucket. I only water when the top 1" of soil is dry. I don't check ph currently, but ordered a kit with ph up and down due to recent issues. Also, my lighting timer recently went out, so I have had the plant on 24/0 as I've heard autos like, or at least can handle this. I'd prefer ALL my leaves look healthy through harvest. Does anyone have any advice?