It's generally OK to reuse potting soil if whatever you're growing in it was healthy. If you've noticed pests or diseases on your plants, it's best to sterilize the mixture to avoid infecting next year's plants. While all the experts we spoke to agreed that potting soil can be reused, they said it could affect plant growth. Yes, you can use old soil in your pots, pots and raised beds.
Just start the season with a special boost that guarantees good results. With a couple of ingredients, you can transform depleted soil into fertile soil for whatever you want to plant. Every year, the containers on my terrace multiply like rabbits. A pot of basil becomes three, a cherry tomato fills a pot so big that I can barely move it, and let's not start with petunias.
While it's a lot of fun to grow plants up close, gardening in pots can cost a small fortune in potting soil. Why waste it? With careful handling, you can reuse potting soil in next year's containers or use it to solve other gardening problems. The first step in reusing old potting mix is to sterilize it. You want to prevent cushioning, a disease caused by soil-borne fungi, as well as stop any other bacteria or pests that were planning to stay until next season.
However, even with sterilization, you should avoid reusing the soil that housed a plant that was sick or had serious insect problems. It's best to throw it away and start over in this situation.