Here's Why You Should Consider Microwaving Your Potting Soil

Did you know that potting soil goes bad over time? It's true; the lifespan is only about two years, due mostly to the peat moss. Also, after using it to grow, your plants deplete their valuable nutrients. The mix can become compacted and even carry disease, weeds, and pests you can't see. For these reasons, many gardeners recommend sterilizing and reinvigorating it before reuse. One of the easiest methods is using a microwave; we'll tell you how.

With prices so high on seemingly everything, most of us are interested in ways to save money. Potting soil, also known as potting mix, gets expensive over time. Consequently, recycling and reusing anything we can helps with sustainability. There are other ways of sterilizing your potting soil besides the microwave, but it's the most convenient and efficient course. We'll still give you instructions on a couple of other techniques. So here's how you microwave and re-energize your potting soil.

How to sterilize your potting soil in a microwave

It's super easy to microwave your potting soil. Start by filtering out clumps of roots, grubs, leaves, or anything foreign. Then just put about 2 pounds into a microwave-safe container with a lid. You'll either need to put a couple of vent holes in the lid or pop one side of it open while microwaving. About a minute and a half should be perfect. When you pull it out, seal the lid or tape over the vent holes while it cools down. After it cools completely, it's considered sterilized. You'll still need to reinvigorate and refresh it before reusing it, but you're almost there.

If you would rather do it naturally, try solarization. You can use 5-gallon buckets with lids or plastic tubs with lids, or you can even use tightly tied black plastic trash bags. Leave them in the full sun outdoors for four to six weeks. This will sterilize any pathogens or pests inside. Doing it in the oven at low temperatures is also possible but not advisable due to the smell it permeates the house and oven.

How to reinvigorate your potting soil before reuse

Now that you have completed the "cleaning" part of the process, you'll want to refresh the mix before using it. Start by deciding what you're going to plant in it first; that way, you can add the appropriate fertilizer. Every type of plant is different and requires various nutrients. Keep in mind that if your potting mix has a lot of peat moss in it, it may now be slightly acetic. Adding some garden lime will help raise the pH, but it's a good idea to check the pH of your soil to be sure.

To be extra sure, you can add some new potting mix to the old, now-cleaned mixture. Another good practice for revitalizing your potting soil is mixing in some compost from your compost pile, or you can reuse it by adding it to the compost pile to begin with instead! Whatever you decide, this is a great way to recycle your old potting mix and optimize it for reuse.