I've seen a few differing opinions on putting ash in a compost
bin and wanted to hear from folks that may have experience with
composting with ash. About a month ago I made a small fire pit
in my back yard with some old solidified concrete bags arranged
in a two-high circle around a pit dug half a foot down. We've
been doing marshmallow and hotdog roasts on the weekend and
generate about half a bucket of ash a weekend. We're use
newspaper for kindling and logs from branches that have fallen or
needed to be trimmed from trees in our own yard. No charcoal,
but occasionally we'll use lighter fluid on very windy days to
help it start (not much, though).
The composts piles are usually composed of leaves, grass, pine
needles, household kitchen waste, and shredded junk mail and old
bills.
I haven't emptied the firepit yet, but at this point I probably
have two buckets worth. I've the third compost bin that's empty
right now and I just put paper and leaf wastes into until I mow
my lawn and turn the pile, so I'll probably store the ash in
there until I mix it with all the rest.
Right now the composted material is just getting used as filler
in my front driveway, so I don't mind the contents just yet.
However, we'll probably be making a flower box for the front
patio soon and I'd love to fill it with composted soil (I'm
guessing I'll need to mix in fertilizer or something, but that's
a question for another time).
I believe the biggest concern with ash is that it will be too
acidic. How large of a quantity does it take to cause this to be
a real problem? If I'm mixing two buckets with a pile that fills
about 70% of one of my 5x5x4 bins, is that low enough to not
affect things that will grow in it later?