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 should be termed as a 'super-plant' it can be used as a medicinal herb, tea, vegetable, animal feed and green manure. Tall and wide spreading, it reaches a height of 60 to 90cm. With large, coarse leaves and flowers which are blue or creamy white grow in spikes and bloom all summer.