The kidneys are paired retroperitoneal structures that are normally located between the transverse processes of T12-L3 vertebrae, with the left kidney typically somewhat more superior in position than the right. The upper poles are normally oriented more medially and posteriorly than the lower poles.
Growing Comfrey in Pots. Comfrey will grow in pots (at least 3 gallon), containers such as plastic tubs, or 5-gallon plastic buckets but they do better when not grown in a pot. They have deep roots so prefer growing in the garden where they get more nutrients. The containers need drainage holes in the bottom. Add fertilizer to the potting soil.
Comfrey tonic makes the best natural liquid feed for plants and is especially good for use on tomato plants. It also works great on all fruit, vegetable and flowering plants. It works so well as it is a very rich source of potash micronutrients, vitamins, minerals and alot of growth promoting agents.