If you are using something like a stock tank or other large container, be certain to make sure there are enough drainage holes in the bottom. If you are looking for an inexpensive filler for the bottom (to save on the cost of potting soil) fill the bottom up to a foot from the top of the container with regular soil from your property or garden area. Then to decrease the problem of weeds, lay a layer of weed barrier on top of the dirt, then top with potting soil.
