Lower leaves yellowing, drying, then dying

I haven't been able to figure out what the problem is, or even *if* there is a problem at all.

Here is a quote that best describes the problem from my most recent entry in my grow journal:

Plant #1 is 36 days old and 20 days into flowering. Buds are now starting to appear in clusters on the branches and at the top of the plant. There is now well over 60 buds on the entire plant. I have been watering each plant with 500 ml of water every 3 days. Considering the size of the pot, this may still be too little. I am concerned because leaves on the bottom of both plants are yellowing, drying up, and dying. There is still new growth at the top and on branches in the form of both leaves and buds. I realize that leaves yellowing and dying is normal to an extent but it is still very early in flowering for this to be happening.

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Is there a problem or am I just freaking out? The plants look pretty healthy for the most part.

Attached images.

might have a bit of a (N) deficiency

Looks pretty deep green and healthy to me. The lower leaves are probably just dying because they are not getting enough light. Just low light necrosis, flouros especially tubes have poor light penetration.

I wondered about that. The leaves that are affected are specifically the ones that are shaded from both my tubes at the top of the plant, and the vertical tubes I installed to shed light on the plants from top to bottom. The problem is that the soil appeared to lose some mass (compaction?) over time after the plant began growing so light is being blocked from reaching those leaves by the sides of the pot. Thanks for your replies. I'm still open to other suggestions from more experienced growers than I, if anyone has any.

MrMcpot said:

I wondered about that. The leaves that are affected are specifically the ones that are shaded from both my tubes at the top of the plant, and the vertical tubes I installed to shed light on the plants from top to bottom. The problem is that the soil appeared to lose some mass (compaction?) over time after the plant began growing so light is being blocked from reaching those leaves by the sides of the pot. Thanks for your replies. I'm still open to other suggestions from more experienced growers than I, if anyone has any.

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Makes sense but compaction is most often caused by poor soil mixtures if you are using quality soil then it should not become an issue. How big is your pot?
A good rule of thumb is 1gal of soil per foot of plant height.

The pot is about 6 gallons and the tallest plant is approaching 14 inches in height. It's an MG mix and yeah, I think it's pretty poor. I'll be changing it for the next grow, adding some perlite and using a better brand with less time-release nutrients.

yeah mg is wayy too harsh if u like adding nutes to your grow, cause everytime u add nutes it also triggers the time release nutes in the soil, so its like a double feeding ,burning plants left right and center

Yeah, I haven't added any nutes though except some magnesium sulphate and some green light tomato bloom spray (phosphorous) in very small doses. I added epsom salts over a month ago and the tomato bloom spray was used for the second time on the largest plant about a week ago. It was also used before I began the 12/12 cycle on the smaller plant, once. It isn't showing any signs of serious toxicity and if it was over fertilized wouldn't it have stopped producing buds or not started at all? It does seem like bud production is slow but the oldest one was only 20 days into flowering today. Flowers have only been showing for 10 days and I'm seeing progress daily. You still think it may be over fert? I was just thinking that the MG stuff had poor aeration without having some perlite added to the mix.

is that tin foil on the wall? if it is make sure its the dull side NOt the shiny side.

im using MG right now and my girls seem to be doing alright, their about 2 weeks into flowering and their budding pretty well. i put a CFL light on the floor facing up so my plants get light at the bottoms.

forget the tin foil, get some mylar. Much better reflective properties. It's pretty cheap too