Microwave sterilization of potting media

[missann]

After reading all the scarry things about fungus and mycellium in potting mixes and peat moss on the "fungicide warning" sticky post at the top of this forum, I have decided to tell you guys something that I do when I am not sure of whether or not my potting mix is sterile...

Soak in consan20 (same thing as physan) for 20 min to half an hour.

Wrap in newspaper

Put in microwave until it steams.

USE THE VENTILATION, as if you cook this stuff too long, it will smell the house up like burned dirt.

I also use this method after I bring my orchids in the house to make sure there are no bugs.
To rid of bugs:
If the potting mix is fairly new, and has only been outside for the summer..
1. Remove the majority of the potting mix from the pot. No need to take every last piece off of the roots and stress the plant.
2. Soak the media in water or consan for a few minutes.
3. Microwave until steamy.
4. Rinse to cool in a strainer.
5. Place media back in pot with orchid.

I have been doing this a bit lately, and I have been successful thus far. No need to put it in the oven on a cookie sheet-it makes your house hot and takes a long time.

Plus, the microwaves have an extrememly destructive effect on living organizms and break down enzymes (which could be a good or bad thing) within the first 5 seconds.

If you don't want to re-use the media on your orchids, or if it is too old to re-use you can microwave it and then dump in your garden to use as a mulch. The microwaving will prevent the media from spreading any disease to your other garden plants.

[Ron]

Hi Missan.
Seems a hell of a lot of extra work.
I would use about 30 by 50 lt.bags of potting mix a year.
All treated pine bark.
I store it in the garage and let it dry out.
When I need it I put the whole bag in a drum and cover with very hot water and leave soak for a couple of days. this get rid of all the crawleys etc.
I find if you open and use it out side there seem to be no problems.
I would never reuse potting mix
Reason, Build of salts, virus's etc.
Mix is cheep.
I never worry about sterilising the mix as they also contain friendly "fungus and mycellium in potting mixes'

Cheerio
Ron

[jbigio]

I don’t do anything with my mix there is also good bacteria in the mix that would be killed if sterilized. But I do collect natural branches from the wood to use as mounts once I cut them to size and then split them in half I soak them in water for an hour then microwave for a half hour . The steam will sterilize the branch killing all pests.

[Orchidementia]

I never reuse potting mix - if I'm repotting, breakdown of mix is usually a reason - nor do I bother soaking before repotting. It's a huge messy pain in the ass. I just buy plain ol' fine bark, make my own mix, repot dry and soak once the repot is done. Easier and cleaner. And I don't have to clean bark out of my microwave!

[Hummer344]

Originally Posted by Orchidementia

I never reuse potting mix - if I'm repotting, breakdown of mix is usually a reason - nor do I bother soaking before repotting. It's a huge messy pain in the ass. I just buy plain ol' fine bark, make my own mix, repot dry and soak once the repot is done. Easier and cleaner. And I don't have to clean bark out of my microwave!

Ohh do I agree here. LOL. No muss, no fuss. Potting mix is to cheap to be going through all those sterilization steps

[Orchidementia]

Originally Posted by Hummer344

Ohh do I agree here. LOL. No muss, no fuss. Potting mix is to cheap to be going through all those sterilization steps

And thanks to your advice, I'm growing outside now, but on a protected balcony, so bugs aren't that much of a worry. On the rare occasion I do see a lingering buggy, home made insecticidal soap or Brookn's cinnamon rinse takes care of it before I bring the plant inside. It seems I have to repot often enough without looking for new reasons to do so!

[missann]

Let me clarify about my definition of "re-using"

I would never re-use mix from one plant to another.

I just meant that it is convenient for me to do this if I don't want bugs in my house, and I can't spray for whatever reason, and the mix is only 2 moths or so old.

I live in a little town where it is very hard to find good orchid potting mix, and when I do find it, it is expensive. Also, I have gone through every Home D. Lowes, Fred Myer, etc looking for plain yard mulch that would suit my needs, and I am yet to find any.

As far as friendly fungus/bacteria, I have a transplant product that I can water with that adds a lot of mychroorizae (sp?) which is the friendly fungus that orchids in the wild have a symbiotic relationship with, and it is what breaks down the organic material to form nutrients that the orchids can absorb.

I just thought I would post my method for the people who are worried about bad fungus in their peat moss, and hoped they could get some ideas from it.

[Orchidementia]

You can make your own potting mix; hell, I do. I get fine bark and add charcoal, perlite, fine pumice and worm castings and store it in one of those ginormous Glad bags. I'm one of the ones who'd rather stab themselves in the face (or try to program a Zune) than use moss. I take that back. I'd never use moss or a Zune.

[Ron]

Hi Missann.
Point taken.
Just added my 2 cents worth.
About 10 years ago I had to travel to the city about 550 + miles return trip.
although I tryied to get a large order from the supplier. It did not work.
Now a group of us get an order in from interstate.
Minium pellet load is 40 bags. Then it takes up a lot of room until it is share around.
Know of the problems you can have in small town.
Before this I use to buy raw pine bark mulched into 1/2 to 1 inch chips.
Put it trought my rather large composts bins for six months , the seive it to sizes to suit my need.
A hell of a lot of work especially as the hobby grew rather quickly.
Still a big hassle to get the load in.
to get the al the friendly fungis in etc. I use a organic pelleted fertiliser with combo of fish, chicken, seaweed, blood & bone products in it.
Best of luck
Ron