Q: I have many containers on my deck. I have recently read that you should dispose of last season’s soil and sterilize the pots before planting for a new season. Is that really necessary? Some of my pots are huge!
A: Unless your plants had some terrible disease or insect problem, I can think of no reason to discard the soil. The only thing I can imagine that would make potting soil less useful is that it has naturally decomposed a bit and now drains slowly. You can easily fix poorly draining potting soil by mixing the old soil with perlite in a 10:1 ratio. Unfold a tarp in your driveway, dump all of your container soil there, mix in the perlite and re use it with my blessings!