Starting to compost and I have questions

[alp]

How do you sterlise it please, @DirtMechanic ? I used my own compost and it is covered with weeds. I'm so fed up. I think they are from the horse manure!

 

[roadrunner]

I'm not sure what you mean by "sterilize".

 

[MoonShadows]

Sterilizing soil is the process of killing all bacteria, microbes, undesirable seeds, etc. before you use it for seed starting or planting.

To sterilize or pasteurize, take a large aluminum-baking pan and cover it with three to four inches of compost, potting soil, etc., insert a meat thermometer in the center and place in a preheated oven, at 200°F., once the center reads 160°F., bake for 30 minutes. Allow mixture to cool thoroughly before using.

https://www.motherearthnews.com/homesteading-and-livestock/pateurize-your-own-compost-zbcz1304zcal

You can also sterilize it outside by using black plastic.

http://homeguides.sfgate.com/use-black-plastic-sterilize-soil-23181.html

There is always the debate on whether to sterilize (pasteurize) or not. Sterilizing kills of so many beneficial bacteria and microbes which are good for seedlings and plants, but if you are plagued with gnats, other bugs, molds, or tons of errant seeds and weeds, you can do it. The beneficial will return eventually.
Of course, if you have a large enough compost pile...at LEAST 1 cubic yard, and it is cooking properly, it should sterilize itself from the internal heat being produced.

 

[DirtMechanic]

What I found over time was all the good molds as in the white aerobic mold and bacteria come again after the pile gets hot. At least all the bad stuff gets gone. For a while anyway, so the plants can at least develop some maturity and self defense before the windborn and insect borne and soil borne pathogens begin to attack them again.

 

[Robert Cummings]

Sterilizing soil is the process of killing all bacteria, microbes, undesirable seeds, etc. before you use it for seed starting or planting.

To sterilize or pasteurize, take a large aluminum-baking pan and cover it with three to four inches of compost, potting soil, etc., insert a meat thermometer in the center and place in a preheated oven, at 200°F., once the center reads 160°F., bake for 30 minutes. Allow mixture to cool thoroughly before using.

https://www.motherearthnews.com/homesteading-and-livestock/pateurize-your-own-compost-zbcz1304zcal

You can also sterilize it outside by using black plastic.

http://homeguides.sfgate.com/use-black-plastic-sterilize-soil-23181.html

There is always the debate on whether to sterilize (pasteurize) or not. Sterilizing kills of so many beneficial bacteria and microbes which are good for seedlings and plants, but if you are plagued with gnats, other bugs, molds, or tons of errant seeds and weeds, you can do it. The beneficial will return eventually.
Of course, if you have a large enough compost pile...at LEAST 1 cubic yard, and it is cooking properly, it should sterilize itself from the internal heat being produced.

Yes one has to be careful not to overdo the sterilisation because you will indeed kill off the good bacteria.I prefer to let it heat up itself and let's be honest, if it's correctly managed it will do so very quickly. Don't think my wife would be too happy if I put compost in the oven Lol!

 

[alp]

I only do mine for sowing seeds and I do mine in the microwave. I had once stratified about 50 or more acer seeds. I bought some compost from a certain diy store and this compost has a Which? endorsement. But soon, the radicles died in the compost which was full of twigs, mould and gnats flying in and out. That really broke my heart as it took 100 days for the radicles to develop and once they were in the compost, disaster struck. After that, I sterilised my compost for raising my streptocarpus seeds and most of my other seeds. I don't want the same to happen again. Also, the supplier in Ireland told me that under government directives, they had to incorporate recycled materials and hence all the twigs, mould and what not. I have switched to another supplier.

 

[DirtMechanic]

This issue of using compost as a starting material is why I favor an elimination of pathogenic particles prior to my efforts towards any form of propogation.

 

[roadrunner]

I see soil sterilization as an act of desperation that only puts one's mind at ease.

We really don't know what's in our soils, it's that complicated and many soil tests don't show much more than the appropriate nutrients for growing garden plants; unless the tests are specifically focused on a particular agent/pathogen.

Let's just look at one type of sterilization procedure: Hot Composting. The entire pile doesn't get hot enough to kill all the weed seeds/pathogens. So you're suppose to cycle the pile to get all it exposed to the heat, but how much heat (in for what period of time) is required to kill all the seeds and different type of pathogens? No one really knows. If you get your pile to a 170 degrees, that's only in the center of the pile, the further out from the center it gets cooler and cooler. So then you cycle your pile and and the area you thought was at 170 degrees, but was only a 100 is now on the outside and never reached the temp you perceived.

Bottom line, I don't believe everyone is cooking the entire contents of their pile at the required temp for the required time to kill all the seeds and pathogens (whatever that temp/time is for the various seeds/pathogens). So why don't we all get sick with all these pathogens in our soils? Because for the most part, the danger is in our minds.

 

[MoonShadows]

Good points @roadrunner

 

[alp]

Desperation or not, I sterilise a small amount of my compost for my seedlings. Not a whole 20L of it. If I don't, I will be wasting my streptocarpus seeds. Some suppliers do sterilise their compost en masse although I don't know the industrial process. Who would buy from them if weeds grew together with or faster than their tomatoes?

 

[DirtMechanic]

I lost every one of this years fall cucumber planting to bacterial wilt born by bugs, and all the fall zucchini and yellow squash after they produced one time. The fall tomatoes are holding up, but they are resistant modern varities. I am well aware that even a hot pile is insufficient in the face of Mother Natures diversity. I have no problem considering the purification of my overused and old plot of a garden.

 

[alp]

I lost every one of this years fall cucumber planting to bacterial wilt born by bugs, and all the fall zucchini and yellow squash after they produced one time. The fall tomatoes are holding up, but they are resistant modern varities. I am well aware that even a hot pile is insufficient in the face of Mother Natures diversity. I have no problem considering the purification of my overused and old plot of a garden.

Yes. I suspect a lot of gardening programmes use brand new screened compost, not like us digging from the garden and use our own compost mixed with manure during composting. I weeded my patch for my hellebores and now it's covered with the same weeds. I'm going to hoe them out before they matt my whole patch. Reused compost should really be sterilised. As @johnny canoe pointed out, he sterilised his old compost and then fertilised it when seedlings come up.

I remember seeing this very loud man on youtube talking about the benefits of compost tea and he addressed the problem of whether using recycled compost or new compost. He admitted that he used new compost and I then realised that all these programmes showing bountiful harvest a la @marlingardener actually got a lot of help from these brand new compost .. whilst we struggle with weeds, bugs, mold, and deficiency in vitamins and minerals!

 

[roadrunner]

I lost every one of this years fall cucumber planting to bacterial wilt born by bugs, and all the fall zucchini and yellow squash after they produced one time. The fall tomatoes are holding up, but they are resistant modern varities. I am well aware that even a hot pile is insufficient in the face of Mother Natures diversity. I have no problem considering the purification of my overused and old plot of a garden.

I think everyone here has lost a plant or plants/crop to some type of disease, just part of gardening. However, your characterization of your soil as: "I have no problem considering the purification of my overused and old plot of a garden." is interesting and makes one wonder....How is the soil "purified" in an old-growth forest?.

Personally, when I see a barren plot of land that has been depleted of all its nutrients, like my very sandy yard here in Florida, I want to heavily mulch it and allow nature to revive it. After all, what is healthy soil? It's mostly just a bunch of dead bodies and animal excrement.

So, I'm still confused about sterilizing/purifying soil

Seems like my sun-baked Florida sand (some might have called soil) was completely purified/sterilized by the sun, but it didn't grow much, but the hardiest of weeds. I never want it to become purified/sterilized again, because that would kill all the life that has come since I heavily mulched it. Life is messy.

 

[DirtMechanic]

When I grew up, my "playground" was actually a Alaskan State Hospital compound located in a village called Bethel. My squirt guns were irrigation syringes. My paper airplanes were used to show me how xrays worked. I remember being chased from the Dentistry because I told a fellow child it was gonna hurt. I watched as my Mother, who ran the lab, grew out cultures in petri dishes. She was charged with managing the disease vectors created by villages sending their children into Bethel for the purpose of meeting State mandated education requirements.

At a young age I became very aware of the small world of biological diversity that exists around us. More than most children, I was made aware that "purification" is a temporary condition. A few unseen particles of disease would magically bloom in the incubators of my mom's laboratory, creating visually striking patterns of mold and bacterial growth in the agar of the petri dishes.

I have become aware that these blooms exist in the fertile soil of my garden. Unempeded growth comes in waves as the sun provides energy in an increasing and then decreasing pattern across the year. Food stock found in the soil also changes density and availability as biological organisms and oxidation processes utilize the environment and heat energy to perform the processes of living.

To correct the blooms of undesireable growths that have built up in my yard based "petri" garden, I recognize that an EPA style soil removal would not be a permanent fix. The small particles would be remaining there in the surround and would re-infect the replacement soil over time.

To neutralize these particles with chemistry and tilling is about all I can do. Some pathogens, such as fusarium, are too dominate to be controlled by organic means. But because pathogens exists in the environment, even innoculating desirable elements back into the soil would be temporary, even seasonally effective, but the soil could be made to be like a starter mix and the late growth cycle attack would then be met by a full grown plant that has enough mass to fight the newly reduce quantity of pathogenic activity that would emerge anew. And maybe I get a few more tomatoes as a result?

 

[DirtMechanic]

However, your characterization of your soil as: "I have no problem considering the purification of my overused and old plot of a garden." is interesting and makes one wonder....How is the soil "purified" in an old growth forest?


It is not. Many plants die because of the onslaught of common digestive molds. They attack even the largest trees via the bark in the bottom 6-8 feet near the ground around my house. Lime-sulfer may be painted to help at the right time of year. It is a vicious attack though, and only the resistant survive. Were trees human, we would describe it as an attack of flesh eating bacteria, but it is mainly molds from the leaf litter decomposition process.