Put it in a pile outside and treat it as compost. Adding some nitrogen will speed up the process, and to keep your pine bark fines 100% pine bark fines, use a synthetic source of nitrogen. Turf Builder lawn fertilizer works good for that. Just pile a layer of about 6 to 8", sprinkle a handful of fertilizer, and reapeat.

Joe

Thanks Joe. So all that's needed is to have a pile of pine or fir bark, add nitrogen (lawn fertilizer) and wait? Do I need to soak the bark in water or is water not necessary?

I thought I read on another site that you can simply place pine or fir bark in a garbage bag, add water, close the bag, and let stand over the fall and winter, and by spring the bark would be composted. Must be I read it wrong, sounds like all I would have is wet bark, not composted bark? Guessing I would need a nitrogen source to start the composting.

Margo

I would also suggest running it through a chipper if the chunks are large first. You want to end up with fines.

I think the bag method would work, but it could take six months. If you have a large enough pile, close to the composting ideal of one cubic yard, you could get partially composted bark in 6-8 weeks using a little nitrogen if the pieces are fairly small to start with. In either case, you do need to wet the bark well.

But, I have a couple questions. Are you wanting to use the finished product for one of Al's soil mixes? You wouldn't want to completely compost it for 5-1-1 because you'd want most of the pieces around 3/8 inches in diameter. Adding nitrogen might be overkill. When i make 5-1-1, I just look for damaged bags of pine bark mulch that's in smallish pieces. It is already partially composted because of the rain.

As for the Reptibark, I've only seen it recommended for the gritty mix, and you don't want it to be at all composted for that mix. It is very expensive (like $20 a cubic foot), and you would need a lot (2 or 3 cubic feet or more) to have the bulk needed to get the compost process going that it seems like a waste. The advantage of using fir bark in the gritty mix is that it takes a very long time to break down, like years.

Good to know! I've had about 8 bags of wet pine bark mulch stacked behind my shed this year. Hopefully by spring it should be composted nicely. I bought the bags this spring on clearance for 82 cents a bag. I did peak into a bag and some of the pieces were a little large. Maybe having them sit around for a year will work out well.

I bought some in February this year, because it was pretty much sitting there for quite some time. I was frozen solid, but once thawed, was perfect for 5-1-1 mix. I dunno that I'd recommend doing the bag method though, unless you have time to waste, because the bags won't have the bacteria to get started on decomp. I'd still just dump it in a pile, add a bit of nitrogen, and wait until spring. The stuff in the middle will be done first. As mentioned, keep it moist, and mulch/shred it up if needed. Then again, if you have plenty of time, just throw the bags somewhere outside, poke holes in the bag to allow rain in & out, and wait it out.

Joe

Chip it up as well as you can. Don't add chemical fertilizers to aid in composting, that's silly. If you already make compost, just add it in throughout the pile. Coffee grinds or manure will provide the nitrogen needed. As you will need more nitrogen than if you were composting brown leaves or cardboard. I do not use cardboard. I've been doing this simple trick for years. 1) for every 50 lbs of bark or woodchips mix in 2 spackle buckets of coffee grinds 2) wet it well and mix. 3) cover and leave for 5 days. 4) remove cover and turn. Adding water and another 5 gallon spackle bucket of grinds. Turn every 5 days. add coffee grinds every 5 days. If it stops heating up or smells turn it without watering and adding grinds until it heats up again. Manure can suffice if you can't get the coffee grinds. The larger the pile the faster it will compost and the only limit to size is how much work you can handle turning it. If you already compost other materials, just add the bark to that compost but remember you'll need extra nitrogen and need to add it often as the bark will use a lot of nitrogen. It takes me from may til November to produce some really great compost this way. Before you use the compost, check the PH, you may need to sprinkle in some lime. I test the maturity of the compost indoors in December with 50% vermiculite, top soil and sand mixed with 50% compost and tomato seeds. 80% or better germination and I'm good. Bark is an outstanding compost ingredient but it takes extra work to use

It's a no-brainer to compost the bark and the way described above is perfect. However, I believe the question was how to compost the bark as an isolated item in order to use it in a container potting mix (both the gritty mix and the 5-1-1 call for composted pine bark fines as a primary ingredient). You don't want to do this in a mixed ingredient compost pile if using for this purpose so the previous methods make better sense.