sterilize soil with steam

[markosillypig]

hi all
i have a steam boiler and would like to know if it would be possible to sterilize soil with steam the steam goes into the bottom of a 45 gaallon drum and goes up through the soil at 100 dc and how long does it have to sterilize for and lastly is 100 dc hot enough

thanks
marko

[pigletwillie]

Can I ask why you want to sterelise the soil, its the micro organisms in the soil that allow a lot of the trace elements to be made available to the plant.

As for your question, 1000 c will kill most stuff, not botulism nor some seeds or fungi, a few minutes would do the trick I am sure.

[rustylady]

Why do you need to sterilize the soil?

[markosillypig]

i saved up all my compost from last years crops i put it in a big wooden box so i thought you would have to sterilize the compost first
it still has some old roots in there

[binley100]

Before the war my grandad used to sterilise the soil from his greenhouse borders in which he grew his tomatoes. He just used to dig out the top layer onto a sheet of corrugated iron and put it on top of a fire. Don't know whether some of the ol' fellas still do it.

[rustylady]

i saved up all my compost from last years crops i put it in a big wooden box so i thought you would have to sterilize the compost first

What do you intend to use it for? I put my used compost on the beds and borders as a top-dressing. Don't sterilise it at all.

[matthew2riches]

Before the war my grandad used to sterilise the soil from his greenhouse borders in which he grew his tomatoes. He just used to dig out the top layer onto a sheet of corrugated iron and put it on top of a fire. Don't know whether some of the ol' fellas still do it.

I've heard about the tin bath and fire

[markosillypig]

all i want to use it for is to pot on my seedlings so if i do not need to sterilize do i need to add nutrients ??

[pigletwillie]

You would be far better to use new compost for the task and use the old as a soil conditioner. It will be great for that bearing in mind that what ever was planted in it last year will have used up any nutrients in it, the new compost will come with a balanced feed suitable for potting on.

[rustylady]

Totally agree with Pigletwillie. I never use old compost for either sowing or potting on.

[Paulottie]

As PW has said above life is short and commercially available compost is much simpler and not too expensive. For larger pots later in the season you can bulk it out with home compost, or leafmould....also the microorganisms are beneficial in balance.

You might argue that you can add all nutrients to a sterile growing medium like rockwool in hyroponic systems but this is quite complicated for domestic situations and probably getting away from the whole point of grow your own.

In times gone by these mixtures were not so readily available. Thus Potting composts were a mixture of some or more of the following: Peat, Charcoal, leafmould, woodash, grit, sand, leafmould, compost, composted manure and topsoil.

For seedsowing you might have had a freely draining sterilised topsoil mix low in nutrients. A supply of topsoil with good fibre content would often be made by stacking turfs. They sterilized, as you say with steam,this will kill most bacteria and all weed seeds and bugs. Firing directly as mentioned above just burns off any organic matter in the soil at the same time.

You can also use chemical methods (normally ***** fluid solution watered on and then it must then be left for a couple of months)...this can be used for tomato beds.(Toms will poison their soil very quickly)..not my scene though it is desirable to remove top spit of the greenhouse border, then sterilize house and replace soil with fresh next spring.

I do have a bucket/colander thing with a kettle element that came from an old gardener for sterilizing soil...also have all the timings and compost recipes in a couple of old books. If you insist I'll dig em out.

I should just choose between loam based or coir based at your local supplier eh!

[mroy]

steaming soil

hi all
i have a steam boiler and would like to know if it would be possible to sterilize soil with steam the steam goes into the bottom of a 45 gaallon drum and goes up through the soil at 100 dc and how long does it have to sterilize for and lastly is 100 dc hot enough

thanks
marko

hi Marko,
thanks for the inquiry. I grow tomatoes in greenhouses with soil as the plant media. I sterilize the soil coz of the ma y pathogens in the soil.
I fabricated a steam boiler from a steel drum (earlier used for Lubricants) and I channel the steam through a box lined internally with a heavy gauge polythene sheeting and filled with the soil.
I bOil the 3/4 filled boiler or drum for 2hrs till it starts boiling and I bOil further for 7hrs.
when done, I keep the box covered or sealed for 12hrs.

anyway, its proving to be pretty effective better than the roasting approach I was using before.

it is a good approach and I recommend it serioul