Don't Throw Away Your Old Potting Soil: This Type Of Plant Can Thrive In It

Sending worn-out items to the landfill rarely feels that great, but finding a new purpose for them always does. That holds true for garden supplies like potting soil, too. Anyone who's obsessed with growing greenery, whether houseplants or garden plants, knows that gardening can become an expensive hobby if you're not careful. Once you really get into the swing of things, it can feel like your wallet has sprung a leak. Either way, it's more fun to spend hard-earned cash on new plants and pretty pots than boring supplies. Repurposing your growing medium can free up some money. Popping it in the pot of a hardy plant is one easy way to reuse and store potting soil so that it doesn't go to waste.

Old potting soil has far fewer nutrients than a fresh batch. Plants deplete the nutrients from soil as they grow, and these nutrients need to be replenished. If you're growing plants that thrive — or at least tolerate — low-fertility soils, then a lack of nutrients isn't as much of a problem. Some of the most common hardy plants that can grow in last season's old potting soil include perennials like butterfly weed (Asclepias tuberosa), thyme (Thymus spp.), and purple coneflower (Echinacea purpurea). These plants thrive in soils with low fertility. Cacti and succulents will also grow just fine in pre-loved potting mix. Fill a pot with old growing medium, plant your favorite stonecrop (Sedum spp.) species, and pop it on your patio. Indoors, any echeveria (Echeveria spp.) will do just as well on your windowsill when planted in used mix.

You can't just start filling planters and pots with the growing mix you used in your garden last year. While hardy plants tolerate poor soil just fine, they may have other growing preferences that necessitate amending old potting mix before using it. As mentioned, succulents and cacti don't need a lot of nutrients, but they do need excellent drainage. If their growing medium stays soggy, they can start to rot. Before you plant that silver jade plant or zebra haworthia in repurposed potting mix, add some grit — perlite, pumice, lava rock, gravel, or coarse sand — to the soil to improve its texture, increase aeration, and limit water retention. Likewise, if you're reusing old soil for hardy garden plants, mix it with some compost for a mild nutrient boost.

Old potting mix can also harbor plant diseases that may spread to any new plants you grow in it, as well as weed seeds and pest insects. You can cleanse last season's potting soil by leaving it in the sun, or you can kill bugs and pathogens by popping the soil in the oven and baking it at 175 to 200 degrees Fahrenheit for half an hour. Once it's cooled, you could even use your safe, healthy spent soil to propagate hardy plants. You can also store it for up to a year. If sterilizing and amending your used growing medium sounds like too much bother, you still don't have to throw it away. Instead, dump it in your compost bin. It's certainly a better solution than sending it to your local landfill as yard waste.