How do you sterilize used compost

[rary]

I have several lts. of compost and soil mix which has been used for growing tomatoes and potatoes what is the best way of sterilizing this so that I can reuse it

[KevinM67]

Surely you can just re-use it without the hassle of sterilisation ?

Maybe just add some BFB to replenish the nutrients.

[ESBkevin]

Do you really want it sterile? Killing all the beneficial microbes means you then have to put in chemical fertilizers or reintroduce the BMs and some own compost as plant feed which will probably negate the benefits of sterilisation.
Otherwise put the compost in the oven about 1.5" deep on a tray and heat for about a hour at 175deg.

I'd just reuse the stuff myself with added homemade compost or leaf mould, alternately stick it on the beds as soil improver or in the compost bin to re-energise it.

[bario1]

Life's too short for sterilising anything that's going to be used in the garden.

[rary]

The reason I want to sterilize the soil compost mix is so that I can use it again for potatoes and tomatoes, now as it is always advisable not to grow potatoes in the same area of the garden it surly must be the same for using the same compost mix

[Cadalot]

I add mine to beds as soil improver especially where I'm growing parsnips or carrots and as brown layers in my daleks between the green layers to re energise it and help the composting process that produces heat as a by product of the composting anyway.

[bearded bloke]

IIRC potty posted on this a while back, as all his growing is in containers he notes what was last grown in any given compost & uses a rotation system.
It's his birthday today, drag him down the pub, buy him a couple of drinks & I'm sure he'll let you know 'what's what'

[MarkPelican]

If you want/feel the need to sterilise, One way I have seen recommended is to put it in a black bag in the sunshine. That way it will get really hot (especially at the moment) and kill everything (including beneficial things like worms).

When I re-use compost (and I don't sterilise it first) I add some Blood, Fish and Bone to the mix to replenish the nutrients.

[rary]

The weather is not that great here, today is the first day this week with sunshine, temp. of 20c and now cloudy, yesterday 16c and no Sun so not that dependable

[Nicos]

As I mentioned on chat thread I'm intending to microwave some hay.
In my search I came across this about soil....

Sterilizing Soil: How To Sterilize Soil

[SusieG]

Oh dear, Nicos ........just read the link you put on re sterilising soil.

I think I would give up growing things if I had to sterilise soil in the cooker/microwave ......the idea just seems so anti everything you learn about all the beneficial nutrients in soil .........and then to sterilise it ~ NO!

[roitelet]

I don't bother and soil/compost heated in the oven STINKS. Last year I used old tomato compost with added fertilizer to grow potatoes without any detrimental effect. After the second use it went on the plot somewhere I wasn't going to grow spuds.

[MarkPelican]

The reason I want to sterilize the soil compost mix is so that I can use it again for potatoes and tomatoes, now as it is always advisable not to grow potatoes in the same area of the garden it surly must be the same for using the same compost mix

I think the reason for not growing potatoes in the same place is to avoid build up of problems cause mainly by soldiers, left over from previous years which could (for example) harbour blight. I would assume that with compost you will be able to make sure there are none left in the compost.

With tomatoes, its the build up of diseases such as wilt. However, I've grown tomatoes in the borders of my greenhouse for several years with no problems as yet. However, I do grow other things in the soil over winter (lettuces mainly) which I would think would break up the pathogens.

[bazzaboy]

I understand why you want to do it Rary as it seems an expensive waste. And there are soil sterilisers for gardeners - e.g. at
Soil Steriliser : Two Wests and Elliott
(that claim to kill off the bad guys and save the good guys....).
But they're expensive and I imagine will send your electricity bill sky high too.
The amount of energy required to sterilise soil would be worrying too on the climate change front if everyone started doing it..... And I certainly wouldn't want it in the oven or microwave!
I've tried re-using compost for (local) show potatoes with generally disastrous results or supplementing new compost with well-rotted manure (not so disastrous but manure can cause staining on the skin so not perfect either...). So now each year I use the previous year's "spent" compost as a mulch or general soil conditioner elsewhere and face the cost of buying afresh.... I guess any hobby has a price! Clearly the cheapest way of doing it is to give up the hobby!

[rary]

Thanks bazzaboy, electricity wouldn't be a problem as I have solar panels, and a low power usage during the day, but the cost of the sterilazr is a bit on the high side, but I do have a wood burning stove, on which I can sit a pot on and heat up the compost, but one of my concerns is of the change to any chemicals that will be in the compost from unused feeding as heat is applied to it, it may be unfounded, or it may be more bother than its worth to make it safe