Sterilizing Seedling Mix

At the end of the indoor seed planting time I like to sterilize my seed starting mix in preparation for fall seedlings and for next year. Why not just buy new seedling mix? Cause holy crackers that stuff is pricey! I can save about $20 each year (which = more seeds that I can buy) with with just a couple of simple steps.

Step 1

When I move my seedlings into larger containers filled with potting mix I save the seedling mix in a bucket.

Step 2

Line a large baking sheet with aluminum foil. This isn't strictly necessary but it makes clean up a lot easier.

Step 3

Fill the pan with seedling mix to a depth of three inches

Step 4

Insert a probe thermometer, set to 180°, into the center and place in a preheated 250° oven. Yes, your kitchen will smell like dirt. You can minimize this by covering tightly with more foil but I don't. I just use it as an excuse to light one of those expensive smelly candles.

Step 5

Monitor the temperature of the soil. It needs to be held between 180-200° for 30 minutes. Don't let it go above 200° as toxins can develop.

Step 6

Remove from oven, cool to room temperature and store in plastic bags, I just reuse grocery store bags.

Now you're ready for next year's seeds!