If I wished to grow a citrus in a container, I would need to buy ChC , S.T.E.M and RootSaver Bags. is this correct.
No, not correct. Besides CHC other good growth medium exist, such as 4 parts pine bark (or cedar, red wood) 1 part peat moss and 1 part coarse sand (not play sand). In actuality you can use most any growth medium that provides rapid drainage while at the same time retains adequate moisture, and aeration. As far as RootSaver bags, I have never heard of them, perhaps you mean the Root Trapper bags. You can use most any container that provides drainage holes at the container's bottom. However, there are certain containers that are better, in some cases much better, than others. In my estimation, the worst possible container to grow a citrus tree in is the common round plastic nursery container. On the other hand, again in my opinion, the best possible container to use is a Root Maker or a Root Builder container. STEM must be provided only if the fertilizer that you nourish you tree with does not already contain trace elements. - Millet
All of the Root Maker products can be found here. www.rootmaker.com/ However, I think they have a $50.00 minimum order. STEM is sold only in 25-lb. bags. However, you might be able to find a fertilizer called Dynamite, in smaller sizes which is a slow release fertilizer that already contains trace minerals. Otherwise, many fertilizers are sold that contain all the trace minerals. Look on the label. - Millet