For city dwellers or gardening novices who do only container gardening, you might wonder: Is it possible to reuse potting soil from last year for this year's new plants? The answer is yes, if you follow a few simple steps. Since old potting soil can be denser and less nutritious, mix in organic matter like compost and fertilizer into the mix. Even some peat moss can be added to help aerate the soil. Since it's impossible to know if disease from last year's plants may be in this year's old soil, choose hearty plants to grow in the recycled mix: Think herbs like rosemary, mint and chive and robust flowers like marigolds and geraniums.