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soil Sterilizing soil

D3monic

D3monic

I bought a bag of happy frog and it has fungus gnat eggs in it. I'm battling the little turds now on some of my seedlings. 
 
I need to pot up soon and don't want to introduce new eggs into the battle. 
 
What are some easy ways I could kill off the eggs without stinking up the entire house?
 
Baking in the oven is probably out. Would the microwave stink?
 
What methods have you guys tried?... Use boiling water to moisten soil prior to pot up?
 
imidicloprid will kill the ones feeding on your plants...
 
killing the ones in the rest of the soil? just bake it in the oven then burn some butter on the stove or something. nobody will figure it out.
 
I baked mine at 175F for 55 minutes.
The soil was pre moistened as well. Just be cautious not to bake it too hot, as I hear it can release plant toxins. There's lots of variations on google.
 
     I used to do this all the time when I worked in a plant pathology lab. I used to fill hotel serving pans with moist soil about 3" deep and cover it tightly with aluminum foil. Bake it at ~200F for a while - maybe 30 minutes and take its temp. I think you're shooting for about 165F for an hour or so. I was heat treating really sandy soil that I'm sure takes longer to heat up than FFHF, so check temps often so you don't overheat it.
     The key here is to "heat treat" or "pasteurize" the soil. The goal is just to kill the plant pathogens. 165F is fine for that. To "sterilize" soil, you basically need to autoclave it, which is difficult to do and will lead to all kinds of phytotoxic decomposition products and your plants will hate you. 
     Heat treating soil is easy and it doesn't smell bad if you do it right. (How bad does a healthy, finished compost pile smell?) Just get one or two of those big disposable aluminum turkey roasting pans and fill them up. If you fill the pan more than like 4" deep, use a trowel to mix the soil once or twice to help it heat evenly. 
     Good luck! Kill those bastiges.  :flamethrower:  I hate them! 
 
 
 
 
 
edit: Correction - Heat the soil to 165F, turn the oven off and let the pan come back down to room temp with the foil on. When the soil is cool, it is done. 
 
Hybrid Mode 01 said:
     I used to do this all the time when I worked in a plant pathology lab. I used to fill hotel serving pans with moist soil about 3" deep and cover it tightly with aluminum foil. Bake it at ~200F for a while - maybe 30 minutes and take its temp. I think you're shooting for about 165F for an hour or so. I was heat treating really sandy soil that I'm sure takes longer to heat up than FFHF, so check temps often so you don't overheat it.
     The key here is to "heat treat" or "pasteurize" the soil. The goal is just to kill the plant pathogens. 165F is fine for that. To "sterilize" soil, you basically need to autoclave it, which is difficult to do and will lead to all kinds of phytotoxic decomposition products and your plants will hate you. 
     Heat treating soil is easy and it doesn't smell bad if you do it right. (How bad does a healthy, finished compost pile smell?) Just get one or two of those big disposable aluminum turkey roasting pans and fill them up. If you fill the pan more than like 4" deep, use a trowel to mix the soil once or twice to help it heat evenly. 
     Good luck! Kill those bastiges.  :flamethrower:  I hate them! 
Click to expand...
 
Do you think boiling water would be as effective as baking in the oven?
queequeg152 said:
imidicloprid will kill the ones feeding on your plants...
 
killing the ones in the rest of the soil? just bake it in the oven then burn some butter on the stove or something. nobody will figure it out.
Click to expand...
 
I've treated with azamax as a soil drench along with some neem oil. Using sticky cards for the adults. 
 
D3monic said:
 
Do you think boiling water would be as effective as baking in the oven?
Click to expand...
 
 
     If you mean just pouring / mixing in a quantity of boiling water into the soil, then probably not. It would be tough to add enough boiling water to the soil so that the temperature of the mix stayed near 165F for an hour (or whatever the recommendation is...). I guess you could add so much boiling water that a higher temperature was achieved in the mud, but for a shorter length of time. That might achieve the same results as heat treating the soil. But now you've got mud to deal with. You'd have to dry it out before you could plant in it. And mixing it in water will probably ruin any texture the soil had, so even when it does dry, it'll probably compact like cement.
     Heat treating soil is super easy and reliable enough to use in a research setting. All you'd have to buy are some of those foil pans, which you could reuse dozens of times.
 
So heating the soil higher than 165/200 releases plant toxins? That's really good to know as I've been sterilizing my soil at much higher temps.
 
FreeportBum said:
I'd just toss it and get some new medium if possible.
Click to expand...
I still have some promix I can use but really wanted to give another brand a chance. So far promix is the only kind i've bought that wasn't riddled with them. MG, roots organics, happy frog have all been busts.
 
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