Generally, bagged, unopened soil is good for up to 2 years if kept off the ground in a well-ventilated space. If your bag is opened, you have a good 6 months to use it. During that period, the soil is breaking down and all those valuable nutrients no longer will be available to feed and support plants. It is always a promising idea to start with unopened, fresh soil to ensure your plants are offered the best base to support them for numerous months. This is especially true for indoor potted plants. If your soil package has a foul smell, is infested with insects, or has mold growing in it, toss it and start fresh. Don’t forget that your plants also do well with a soil refresh. “Plants typically benefit from being repotted every 12 to 18 months, depending on how actively they are growing,” says Marino. “Some slow growers, like cacti, can call the same pot home for years but may require a potting mix replenishment (new potting mix or fertilizer to provide fresh nutrients - but not more space). The growing season, early spring through late summer, is usually the best time to repot your plants. Because your plants are actively growing during this time, they’ll get the most out of additional space and fresh nutrients.”