How can i sterilize my outdoor compost for use indoors?

I’ve had infestations of fruit flies and worse, fungus gnats, before. Mainly on houseplants but it seems as if i can’t bring anything from outside without bringing in a pest or disease. I’d like to use my super rich compost inside. Does either microwaving or baking kill off the worst culprits? Will it kill all the beneficial fungi and bacteria too? Anyone have 1st hand experience? TIA!


Bake it in the oven or maybe under clear plastic a few days to get it hot enough to kill everything.
Clear plastic actually will get hotter underneath than black plastic.
Too bad as compost that’s alive is better but I agree bugs are not welcome in the tent.

2. How To Sterilize Soil In The Sun

This method works through solarization, by covering your soil with layers of plastic. The heat from the sun will build up the temperature of the soil under to kill most of the bacteria, diseases, weeds, and pests.

Sterilization through solarization can take place in a couple of different ways. The methods you choose will produce similar results; which one you choose is a matter of preference and budget.

If you are sterilizing small quantities of soil, you could use plastic bags to create a mini-greenhouse effect by placing the bag in strong sunlight to absorb the sun’s rays. It’s important to lay the bag flat so the soil forms a thin layer of a couple of inches.

From Professor Google,

For large areas, you try shoveling soil into thin layers spread between large sheets of transparent plastic. The basic principle is to heat through the soil, so thinner layers will work better.


Thanks! Good info. Tent!? I wish i had that much space lol! I’m actually experimenting with growing in a book case. Micro grow with only about .28m³ of volume.


I always deal with fungus knats 1st couple of weeks but something in jacks 321 kills them i also line my tent with fly paper and that catches a good amount of them too

Interesting. I always thought it was because I stopped using soil and switched to coco. However, when I made the change I also switched to Jack’s.

Mosquito bits. Fungus gnats are only a pest when they’re adults, but the larvae are what do the damage. You can sprinkle them on the top layer and water it in as you feed. Or you can warm up a gallon of water, put mosquito bits in, let it sit for a bit, then strain the bits out. The latter example is more direct kill. Letting the soil dry out also helps keep them at bay, but doing a living soil, you have to keep it moist, so that’s probably not the best bet.


Where did you get your Jack’s???


Yes you can put compost in the oven and bake to sterilize but it will sterilize both good & bad. Also your house gets that burnt dirt smell like from wild fires. But you can reinoculate with good microbs after. A couple of worms or some LAB/IM from Korean Natural Farming should get the new biology off to a good start.

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Yes if hott outside cover with a tarp and leave it set for a couple few days then uncover mix up and cover again otherwise if u bake it in oven which don’t smell good but does kill off the nasty unwanted bugs. Bake at 180 to 200 for 30 to 60 mins let cool in a clean bug free spot before u add to pots u may wanna mist the medium with some microbes or so to get them in and starting to work some spray the whole medium with tribus or something like so when u fill and water they r there and ready to start work. Good luck. Bugs sick ass for sure.