Sterilizing compost

**jimmy cee** 12/29/2015, 4:51 pm

Do you use compost for a seed starting mix ? I do and have had good results, however I am always ready to test other stuff.
Do you use sterilized plant medium or sterilize it before using ?
If in the compost piles when temps reach 160 deg.F the seeds are all killed off, how about any bad bacteria ?
Do you think those lower temps would do them in also ?
I have a couple of crock pots ( slow cookers ) I use for warming paints, water, etc...shop stuff, not for food stuff..
I'm considering filling one up with compost, putting on the lid and cooking 1 pot of compost.
Crock pots will not over heat, if I'm not mistaking their max temps are in the 170 Deg range..not exactly sure about that, gotta check it out though...

**sanderson** 12/30/2015, 3:38 am

I'm trying something new this spring - oven baked used MM. I used an aluminum turkey pan, a little water so it steams, and covered tight with alum foil. 350*F for 30 min. Cool and let dry out for storage. 160*F reached in hot compost piles kills many organisms but not all, especially heat resistant ones such as Clostridium botulinum and perfringens.

**jimmy cee** 12/30/2015, 6:31 am

sanderson wrote:I'm trying something new this spring - oven baked used MM. I used an aluminum turkey pan, a little water so it steams, and covered tight with alum foil. 350*F for 30 min. Cool and let dry out for storage. 160*F reached in hot compost piles kills many organisms but not all, especially heat resistant ones such as Clostridium botulinum and perfringens.

Thanks, I wasn't aware of that.

littlesapphire 12/30/2015, 9:59 am

sanderson wrote:I'm trying something new this spring - oven baked used MM. I used an aluminum turkey pan, a little water so it steams, and covered tight with alum foil. 350*F for 30 min. Cool and let dry out for storage. 160*F reached in hot compost piles kills many organisms but not all, especially heat resistant ones such as Clostridium botulinum and perfringens.

Sanderson, I've heard that if you cook your soil/compost higher than 200 degrees it creates a chemical that's toxic to plants. That may be something you should check into. The instructions I've read for sterilizing soil/compost are to spread it in a roasting pan and cook at 200 degrees for 30 minutes.

Jimmy, I like the idea of a crock pot! I'd never thought of that.

I'm pretty lazy with seed starting. I start my seeds in sterilized seed starting mix from the store or fine vermiculite, then once the seedlings get two true leaves, I transplant them over to either MM from my garden or some MM I make up with homemade compost. I haven't had any problems with damping off with this method. However, the year I started everything in straight unsterilized MM, I lost about half my seedlings.

plantoid 12/30/2015, 7:31 pm

Jimmy our electric crock pot will boil the pot after several hours ... fairly bubbly on high & the odd bubbling on medium. it does not boil on low setting.

As I have some stratified seeds in the refrigerator that I don't want to see attacked by nasties as I try & grow them I think I'll give it a go sterilizing on low with a pint & half pint of water in the compost and set it up on a timer out in the garage overnight.
For I can imaging it making a bit of a stink if not in itself ....... but by Alison finding out what I've done instead .

I'll use the /strained drained off cooled down liquid to water the seeds & plants in the green house .
It should be able to get reinfected with good & bad bacteria if stored in an open jug in the glasshouse.

**jimmy cee** 12/30/2015, 9:54 pm

I'm going to try this asap, maybe next week, toss a few seeds in containers just to see what develops..should be in the least an interesting project when cold sets in.
Right now I am still playing with my compost, just combined 3 areas into one 27 cubic foot bin...mixed in the fifteen 5 gallon buckets of horse manure, about 400 lbs of coffee grinds...bursting at the seams.
The steel rods I have inserted are almost uncomfortable to hold on when removing them, my feel is my temperature gauge

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