With spring around the corner, your outdoor window boxes and garden pots may still have last year's old potting soil inside. So the question is, is the old soil still good? If you are repotting a household plant, can you reuse the old soil? The answer is no, unless you are absolutely certain the soil is free of any disease. Since it can be impossible to tell, the best way to reuse potting soil is to sprinkle it in the yard, where the sun will have a chance to "bake" the soil, killing any disease. The soil eventually will blend right into the ground.
ANDREWS MCMEEL SYNDICATION