How to pasteurize your own soil
Okay, your houseplants have been sitting in the same soil for the last year and a half, the roots are coming out from the bottom of the pot and your houseplants is looking, limp, so the best thing you can do for your houseplants is to repot it in a larger pot. But in order to do this you need a lot more soil; so out to the backyard you run to scoop up that nice soil that is sitting around doing nothing.
But not so fast! that backyard soil needs to be treated before it can be used, which means you must pasteurize or sterilize it. Why do you have to pasteurize it, you ask? The reason is because that backyard soil contains weed seeds, viruses, bugs and other organisms that could hurt or kill your houseplants.
The easiest way to pasteurize soil is to use your oven. You will need a baking pan that is at the least two to four inches deep. Cover the pan and dirt with aluminum foil, stick a meat thermometer through the foil in the middle and put the pan in a per-heated oven of 200 degrees. Cook for about one and a half hours, check thermometer every half hour to make sure your pan of soil does not get above 200 degrees, turn down the oven a little if it does. When done cooking take pan out of oven and let sit for 24 hours. You are then ready to repot your plant in your own homemade safe soil.
Oh! By the way now that you pasteurized your soil – you not only killed what was bad in your soil, you also killed what was good in it so you will want to mix in houseplant fertilizer before you start to repot your plants.
Now if you don't want to go through the procedure of pasteurization, you're more than welcome to go out and buy the per-packaged mix from the store, but where's the fun in that?
1 part topsoil
1 part rich humus
1 part clean #4 builders sand
Basic Soil-less Mix
1 part #2 grade vermiculite
1 part shredded peat moss
Cactus and Succulent Mix
1 part sharp coarse builder's sand
1 part standard potting mix