The green houses sterilize the dirt, but even then, moist dirt soon starts growing plentiful bacteria/creatures..

Such a problem is easily and safely solved with true essential oils. Many are known to work---but I like wild oregano for everything, just for the fact new born babies do well on it and yet if you read the Cass Ingram book--miracle of oregano oil===wild oregano sterilizes safely.

I have a room inside a closed metal barn---no light, no windows---I have not went in for a year or 2 and was pressurized the white walls were black--with mold. I added wild oregano to a quart of water in a typical water/air room device and added a few droppers---the room is 32 wide, 24 long, 10 feet tall---in 2 weeks I went back to the room----the walls were white and at the bottoms of the walls, was black powder-----dead mold.

More potent is Essential Oil of Cayenne / Chili----put that stuff on a tree and no bug wants near it.

Essential Oil of Garlic--expensive, but potent stuff--

I have used wild oregano oil for 26 years for everything-----in a 150 gallon aquariam it keep the water clean.

in my 750 old hot tub---it keeps the water clean, have no used a chemical for close to 20 years.

BUGS love moist dirt, annual plants / seedlings-----real wild oregano oil will make everything "better", our kids grew up from baby onward with wild oregano oil and today ad it to water to just make it taste better---they never seen a nurse.md/dentist after they were born-- I would use as much as it takes to solve you issue----

MH