Jim I have whole encyclopedia sets on plants that does not address your question. It is assumed you are gardening in good garden soil without ever being very specific about what that is. For myself I have had a good lab test my soil when starting on an unknown piece of ground. Before doing this ask for a sample of the labs report. some are next to worthless. A good lab report will tell you what your soil lacks to make it a "good garden soil". It should also tell you what course to take to improve it. I don't think you will find a recommended "diet" for the species you decide intend to grow. Al

Biotin is a water-soluble B vitamin that plays an important role in metabolizing the energy we get from food. Biotin assists four essential enzymes that break down fats, carbohydrates, and proteins. Some of the better food sources of biotin, are egg yolk, liver, kidney, pancreas, milk, soya and barley Here is a link that might be useful: Biotin

I looked at the Innova, Ziwi, and Pitcairn(sp) information. Since I do not have cats, I did not look there. the two websites simply say what every other dog food manufacturer says---we do it better, use better ingredients and are safer than any other manufacturer. (They both use grains, BTW) There is nothing abou poisoning by products or any other threat. the Pitcairns web site is best summed up by this paragraph---- "ANHC was founded by Richard Pitcairn, DVM, in 1986 as a clinical and teaching center for the understanding and use of homeopathic medicine in the treatment of disease. We also emphasize the use of excellent nutrition using home-prepared & raw foods." No telling what stories they tell to convince people of the horrors of using pmanufactured foods.

The pepper plant is far too yellow but it is primarily the old growth that is yellow - that indicates excessive watering. While the new growth, somewhat better color but fading, has curled edged leaves - also indicative of a watering issue. So best guess on it is over-watering and in need of some nutrients. Peppers prefer to dry out some between waterings and do not require nearly as much water as tomato plants under normal conditions. The "tiny tomato plant" - can't really see it well enough in the photo except to note again that it is pale - especially compared to the one in a different location. So again I suspect lack of nutrients. As Dan said many factors can contribute but by far the 2 most common are water issues and nutrient issues. Address those two factors - cut back on water and feed them - and see if both don't improve. I also suspect nutrient issues because you mention that herbs are doing well. Herbs can thrive in nutrient poor soil, they prefer it in fact over high nutrient soil. So I'd sure give some thought to feeding your tomato and pepper plants. Dave