Answer: A cubic yard is three feet high by three feet wide by three feet deep. That is 27 cubic feet. Your box is roughly a foot by a foot by four and a half feet. That is roughly only four and a half to five cubic feet. Most bagged soils will tell you the number of cubic feet in each bag or you may be able to eyeball it by measuring the bags. You would want to use a commercially formulated potting mix for container plants. Topsoil and similar materials are not recommended for planter use for several reasons including that they tend to compact too much. I hope this helps.
Q&A Library Searching Tips