Sterilizing potting soil is a great way to help nurture seedlings and delicate plants by removing pathogens and insects that potentially cause harm. Improve your garden with the help of a professional landscaping designer in this free video.
Hi, I'm Marci Degman, the aspiring gardener, and today we're going to talk about how to sterilize your potting soil. The reason you would want to do that is because seedlings tend to be very, very sensitive to pathogens, insects, or anything that would get into your potting soil. Most of the time your everyday potting soil is OK for house plants and other plants, but seedlings need every bit of help that they can get. So, even though you buy this and it says that it's sterile, sometimes while it's sitting stored at the store, garden center, maybe in your potting shed, pathogens and things can get in the tiniest little holes. So, it might look good, you want to inspect it of course for insects or anything, but even if you don't see anything, there can be pathogens. So what you want to do, the first method that I'm going to talk about is baking. And what you want to do is get a good baking dish. I like to use a shallow one because that way I can stir it and I can keep an eye on it. You don't want to leave it in too long or have hot areas that are burning that you don't notice. You don't want to change the soil, you just want to heat it up. The best temperature is 180 to 200. Most of our ovens don't want to go to 180, so if you have 200, set your oven there. And you want to bake your potting soil for 30 minutes. But don't walk away and ignore it. Fill in maybe just a little bit more. Put it in and about every five to ten minutes check it and take a spatula and move it around so it doesn't get too hot. If you start to notice any changes in the potting soil, you don't want it to burn or turn black. Take it out. It's done. The other way that you can heat it up is in the microwave. Th bad part is you can't put a very big pan in there. But the good part is you only have to put in the microwave at high for two and a half minutes and if you're doing just seedlings, all you need is a little bit at a time. So those are the two main ways that you can sterilize potting soil. If you have a really big amount, say for outdoor projects, things that you really need sterile soil for, you can pile up a mound of soil, cover it in black plastic and let it sit in the sun. That's called solar sterilization, and today we've learned how to sterilize our potting soil.