Q: I have some styrofoam packing. Can I break it up and mix into garden soil to make it lighter and easier to drain? I know potting mix has styrofoam mixed in already.

A: The white balls in potting soil are perlite, not styrofoam. Perlite is made by super-heating a glassy rock that occurs in the western U.S. as well as in other parts of the world. The rock contains water, so when it is heated it expands like popcorn. Because perlite is very porous, it holds moisture and nutrients for plant roots in potting soil. Styrofoam, on the other hand, is not porous and it tends to float out of soil and blow in the wind. You are welcome to try using styrofoam but I think you will be disappointed.