Senior Member
Posts: 168
Joined: Mon Jun 01, 2015 7:48 pm
Location: Zone 5b

Composting Diseased Plants - What survives the winter?

I have a cold compost pile that I tend to. I have been dealing with a number of diseases, predominately related to my tomato plants. I just want to be sure that the spores of theses diseases won't survive the wisconsin winter (Zone 5B) and encourage disease next year. For example, as far as I know, powdery mildew makes its way north every year (migrating like birds and bugs). So I wouldn't worry about adding powdery mildew infected plants into my compost, as the spores will die during the winter. I know hot composting could also alleviate some of my worries, but that isn't happening.

Thoughts on this subject are apprecaited. I've found a number of different viewpoints on this. But it seems the big questions are A. If the spores survive the winter and B. If they do survive the winter, how much greater is the probability that your plants will be infected by the compost and not just their arrival with the warmer air.

Greener Thumb
Posts: 1030
Joined: Mon Oct 19, 2015 9:12 pm
Location: central Ohio

What I have done, but can't be done in some areas, it to put the diseased plants in a bonfire then spread the resulting ashes in the yard. Not many diseases survive fire.

There are many diseases and pests that will survive cold temperatures.

Posts: 13994
Joined: Tue Jan 01, 2013 8:32 am
Location: Hawaii, zone 12a 587 ft elev.

Unless you are hot composting for sure, it is better to trash the diseased plants. Most diseases do not survive if you compost long enough but viruses will. Some perennial weeds will also survive composting, even hot composting.

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