Boiling water to sterilize & re-use potting mix?
Although I learned a lot by experimenting last year, I'm still very much an amateur, so I would appreciate a bit of advice!
I have quite a few large containers filled with last year's potting mix, which was roughly 5% perlite, 5% vermiculite, 20% coco coir, 10% composted manure, 30% Miracle Gro potting mix, and 30% compost. I'm very much on a budget, and aside from the compost, which is given out free by the city, I shelled out quite a pretty penny for this stuff. The thing is, last year my tomatoes had blight, and something similar seemed to happen to my strawberries (though this could have been due to my Topsy Turvy strawberry planter-- please never get one of these. Don't even get me started!).
So my question is-- if I boil a considerable amount of water and pour it through the soil, will this kill the blight? Obviously it would also kill any beneficial soil microbes too, though because the containers have been outside in the cold all winter anyway (it sometimes gets as low as -40 celsius here in Montreal), wouldn't they be dead anyway? How could I re-populate these soil microbes, by re-introducing new soil? How much would I have to use? Finally, what do you think is the most likely culprit for introducing the blight? I'm thinking likely the compost, or perhaps the manure? I'd hate to simply re-introduce it again by re-using whatever the source was, yet being a frugal gardener, I find it hard to throw out compost or manure!
OK, that was way more than one question, sorry guys :p
Thanks in advance!