Red stems on the leaves can be perfectly normal and is not caused by light, but genetics. There are even some strains called "red stem", so I wouldn't be too worried at this stage. As for your leaves, and after looking at your diary, I would suggest there are a few things going on. Firstly, you referred in week 2 to a "transplant" feed. After transplanting, you need to go softly on your plants while they recover from being transplanted and also given time for their roots to "organize" themselves. Best to just give them plain water and wait until the leaves have picked up and the roots have started new growth, usually 1-5 days later, depending on how much trauma they received during the transplanting operation. Next.... your plants are still quite young and in fresh soil. Your feeding routine is really heavy for such young plants in fresh soil, and I believe the symptoms you are seeing on the leaves are caused by too much nutrition. Even though your nutrients are organic (way to go!!), you can still cause soil toxicity by using too many things at once and trying to really force feed your plants. For example, you are using grow microbes, roots excelurator, amino treatment, recharge and multi zen, products that are all basically doing the same thing for your plants. Try cutting back on what you are giving your plants for a while, just plain water for 5-8 days to try and reduce the build up in your soil, then using the products I just listed, in a rotation - meaning, one feeding giving recharge, the next feeding amino treatment, the next feeding grow microbes etc., that way each product has time to work and "do its thing". At the moment your soil and roots are having a real battle with the nutrient soup you are giving them, and they are probably "fighting amongst themselves" for dominance, with no one winning, and your plants losing/suffering. Seeing as you are keen on organics (hooray, way to go!!), organics should be a gentle, soft and natural system of growing and not a forced, overfed, push, push, push method. Your plants can only grow so fast, bombing them with everything under the sun will just cause problems. Your plants should bounce back, once your soil has had bit of a break from too many things at once. Hope this helps.... Organoman.