Soil steralisation.

[m0lsx]

I found the following online & although aimed at gardeners I thought it may help some. Or even possibly produce some debate about the use of top soil, treated or untreated.

https://herbsathome.co/how-to-sterilize-soil/

Sterilizing soil is a process that has been done in commercial greenhouses, and by agricultural producers for quite some time......

There are two basic methodologies used to sterilize garden soil and sterilize potting soil: chemical treatments and heat treatments...

Heat treatments raise the temperature of the soil through steam or direct, dry heat to a threshold where the harmful organisms, fungal spores, weed seeds, etc. are unable to survive, and die. Heat treatment is often called sterilization, but this is a misnomer as the soil isn’t completely sterile at the temperatures induced.

It does kill weeds and pests depending upon the internal temperature reached and the length of time the threshold is maintained. Most instructions recommend at least 30 minutes at the given temperature to kill specific organisms in moist soil or potting mix.

Target Temp Organisms Killed when Temp Sustained for 30-minutes


120℉ water molds (oomycetes)
145℉ most plant pathogenic fungi, bacteria, and viruses, worms, slugs, centipedes
160℉ plant pathogenic bacteria, soil insects
180℉ weed seeds
212℉ heat resistant plant viruses and weed seeds

Heat treatments can be harmful if the internal temperature of the substrate is allowed to get too high. Excessive soil heating may increase the chance of phytotoxicity due to soluble salts, manganese toxicity and toxic organic compounds.


Soil mixtures high in readily decomposable organic matter (manure, leaf mold, compost) are more likely to give injury when exposed to excessively high temperatures than mineral soils or potting mixes where the organic matter has completely broken down.

The site gives 4 different methods of home heat sterilisation.

 

[Whitelightning777]

The problem with sterilization is that it can interfere with bioactive enclosures.

The other issue is that while it might kill hostile life forms, it won't destroy harmful chemicals such as herbicides or pesticides or industrial chemicals.

If the temperature is too high and actually chars the substrate, the products of combustion can cause issues.

Unless you have some specific issue like substrate with a known mold problem or ant problem, it's a waste of time.

I only had to sterilize substrate once when I don't ran out and the little bit left had ants.

 

[m0lsx]

The problem with sterilization is that it can interfere with bioactive enclosures.

It should not. It is used by both commercial operators & gardeners to sterilise potting soil.

The other issue is that while it might kill hostile life forms, it won't destroy harmful chemicals such as herbicides or pesticides or industrial chemicals.

Yes, but personally I would not use soil I did not know. And chemicals in commercially available top soil is probably the biggest issue. As we cannot take precautions, other than not using commercially sold top soil, to prevent it being an issue.

 

[Whitelightning777]

To do bioactive after sterilization, you need a non sterile source which kinda calls into why you bothered in the first place.

 

[m0lsx]

To do bioactive after sterilization, you need a non sterile source which kinda calls into why you bothered in the first place.

From the above linked to site.

Research has shown that even sterilization significantly reduces the population of beneficial soil bacteria, it does not eradicate them completely. After sterilization, certain species such as Pseudomonas and Bacillus, quickly recolonize the soil and their populations reach high levels within a short amount of time. This quick recolonization overrides the initial reduction in populations through sterilization.

 

[octanejunkie]

It is for all the reasons mentioned here that I don't use soils for my pets and opt to make my own substrate mix from known good/clean components. Coco fibre, peat moss, sand, vermiculite, sphagnum moss, etc

 

[menavodi]

I use soil. Organic. I never sterilized mine. Never had a problem, but I also use plants and that might help to keep the soil good...

 

[m0lsx]

I also use plants and that might help to keep the soil good...

What plants do you use?

 

[menavodi]

What plants do you use?

Plants I use since years:
Epipremnum pinnatum, small ferns like Nephrolepis exaltata. Ficus pumila and also Peperomia caperata