As long as it is a lumber mill that cuts trees into boards, it should be fine. If it is a mill that shapes plywood, or pressure treated wood with arsenicals, I'd be careful of bad chemical residuals. Those chemicals can be leached out by soaking with water a few times, but are best avoided entirely.

Of course, if you want prompt composting action, you'll need to supplement the pile with some nitrogen source.

@Jim Mat ... not after it's composted.

I use pine/juniper pellet fuel as kitty litter, and the urine-soaked sawdust is a large proportion of the compost pile (with dead leaves and kitchen scraps). The veggies in the bed that is about 60% compost and 30% sandy desert dirt are thriving. The flowers in the bed that was top-dressed with 4-6 inches of compost are thriving.

The Hugelcutur community is pretty wise about what woods not to bury. Obviously black walnut. Cedar as well. I've seen no references to allelopathy of pine *wood*. In the PNW I used to compost fir and pine all the time. It is, however, well documented that pine *needles* are allelopathic.

Some pine needles do have some allelopathic properties, not all. This is to limit competition for nutrients for any plants that might grow near the parent plant, however, the shade the trees provide is more of a deterrent to growth than the needles would be unless they are in quite thick layers. The groves of White, Red, and Austrian, pines I have do not inhibit under growth very much at all.

Pressure treated wood makers have not used Arsenic in the treatment formulas since about 2004. However, most knowledgeable people will tell you to avoid using Pressure Treated wood or plywood or oriented strand board products in your compost.

kimmq is kimmsr

You can actually still get CCA treated wood for certain applications - for example a post that's going into the ground. At least you could awhile ago. I bought 6x6 timbers for a building in 2009 that were CCA. The lumber yard said I could only use them for 'ground contact' applications. The stuff did work better than what replaced it, despite its toxicity.

Anyway I echo the advice about what kind of facility. Cabinet shop, millwork, lumber sales with a saw for cutting to size for customers, I'd be making sure there's no treated wood. I'm not personally too worried about plywood glues. Sawmills, all you have to do is avoid species that don't decompose.

Any non-treated wood can be composted and will decompose.........some species just take longer than others. And if you are composting, there is NO issue regarding allelopathy. Most allelopathic reactions are very plant specific and all will be effectively negated by the composting process.

The primary issue with composting sawdust or wood shavings is that it is a very dense carbon source and requires a pretty serious amount of N to offset. Just be sure to provide plenty of 'greens'.

Thanks everyone...I just spoke to the lumber mill...the rep said mainly local species of wood products are sold there...(meaning oak, pine and maple)...he also mentioned that very little of their wood products are pressure treated and that no arsenic is used...at $2.50 cents for a large plastic bag...I guess it's worth it....

I'm not a fan of wood shavings for a C source. In a crunch maybe but it isn't all that great as a composting feedstock.

Thanks Lloyd! So if not wood shavings, what do you recommend for a primary carbon source? Leaves? Straw?

If you have the wood shavings, use them. You might need to find a high nitrogen something if you want fast composting, such as chicken coop litter.

My primary carbon source is locally produced pellet fuel - lots of it ($5 for 40 pounds). We use the pellets in the cat litter boxes and the bottom of the kitchen scrap-collecting bucket. The pellets expand and soak up any moisture, turning to sawdust. The urine-soaked sawdust (minus feces) and kitchen scraps get dumped into the compost bin, along with whatever yard waste and dead leaves we have (not much).

It decomposed into a nice, coarse, moisture-holding soil amendment is about a year. This soil devours organic material.

IMO there is no better C material than leaves. Lots of readily available C with numerous micro-nutrients. Easy to handle and store. I get them by the truckload and usually over-winter* 30 bags or so. After that would be straw, and after that would be a wood product, paper or cardboard.

* Winter up here starts in early November and goes til the beginning of April. Temperatures of -20C and two-three feet of snow are not uncommon.

Agree with Lloyd. I've used wood shavings and sawdust from my own shop, but only when I had masses of greens (grass clippings) which you can't keep around, and at the same time I had no leaves or anything better. It works, but it may take longer.

Also if you can keep your sawdust/shavings in an open bin and let the rain get to them, they will start slowly decomposing fungally, which will help speed up the process when they get into the compost pile. If there are any adventurous gardeners in the family (particularly males), a little liquid nitrogen addition helps it along too.

With regard to "liquid nitrogen", there is an amazing lack of information about how to "do it" properly. Urine contains urea, which hydrolyzes with water and a very common natural enzyme called urease to produce ammonia gas. That's the nitrogen-containing product. Of course, urine carries it's own water, so it just needs contact with urease to set it off. Urease is *everywhere*, in soil and even blowin' in the wind. So urine applied to anything will start producing ammonia, and in order to be "nitrified" into plant-usable nitrogen, the ammonia has to be trapped in the soil. The breakdown lifetime of urea (depending somewhat on temperature and pH) is just a few days. So ... you need to use fresh urine -- don't pee in a pail and dump it every week. Also, don't pee on the surface. The ammonia will just float away. Bore a hole in the pile with a stick and put it down the hole. Seal the hole up when done.

Be aware that urine may contain a lot of salt (depending on diet), so direct application to plants isn't advisable. That salt will leach out of the compost pile, though.

But that's exactly right that fallen leaves at least contain a little nitrogen to get the compost pile humming. Sawdust and wood chips have almost none.

I applied collected pee onto the stump to speed up its' decay about every week 1-2 ga . No any significant changes of that stump were detected until one beautiful day it was eaten till ground by deer. Poor creatures. :)))

As I tried to explain, "collected" pee is probably dead, re nitrogen production. Needs to be pretty fresh to do anything at all. Urea is NOT a standard nitrogen fertilizer. It works differently. The fuse is lit the moment it comes out. Amazing how little really biochemically informed info there is about using urine as a fertilizer, especially considering how much is written about it. Of course, the internet these days is mostly just viral copying.

In my case, after chewing pee-seasoned stump, deer left some their poop nearby, which may be called "Nitrogen product" .

Formally, what the deer left behind is a "nitrogen product" only if it is used while fresh. Once it gets old, a lot of it is just "organic matter". What makes manure nitrogen rich is the urea in it. Although if it dries out before the urea hydrolyzes, active urea could be left behind. Small pieces may dry out pretty quickly, but in large "pies" that stay wet for a while the urea continues to hydrolyze.

Wait! This wood is not free? You have to pay for it??? In that case no amount would be good. Surely you have access to leaves or your neighbors' leaves to provide carbon for compost. You shouldn't have to pay to make your own compost.

I'm not sure nitrogen in pee is so efficiently and instantly transferred to the atmosphere. I could be wrong, but even if I pee on top of a sawdust pile, it's going to soak in. I've never tried hard to make sure it was buried deeply, and I can see effects on the material, so it's not being lost. I will agree there is some good advice here though, especially about storing pee, I would never recommend that. Put it directly on the ground or in the compost.

If you just leave pee in an open bucket, exposed to the atmosphere, and the urease blowing around in it, the nitrogen will largely be gone in a few days. Unless you're unloading gallons of pee on a compost pile, it's not going to sink that deeply into the pile. If you pee on a pile, and you can smell it there, that's ammonia/nitrogen you're losing.

I should say that it is well known that a diet heavy in protein often results in strong ammonia smell in urine.

Responding to the original question, when I can, I try to incorporate some woody material in a compost pile. It tends to be a small minority of the ingredients, and it's usually been through my chipper, so the particle size is small. I'm certain that it does not finish decomposing for a long time, but I'm thinking that as long as I don't bury it in the soil, as long as I use the compost as a mulch and apply it to the surface of the soil, it won't hurt much. My hope it that because it decomposes slowly, it has a longer-acting effect on soil chemistry. The leaf and grass components of my compost will be mostly be consumed or absorbed in a year or two. The woody material might linger longer.

I have run blue pine needles through the chipper/shredder. Some of that went into a batch of compost, but most of it was applied under raspberry plants. The raspberries seemed to like that a lot.

Slowly decomposing bits of woody material have a long-lasting effect on water holding, texture and aeration of the soil if you dig them in. It's not going to magically suck all the nutrients out unless you are digging in huge volumes of wood chips from the inner part of the tree.

Our normal shreddded yard waste was "ramial" material - the twigs and small branches, often with leaves - that was small enough to run through the chipper or shredder blades. That stuff composts quickly because of the fresh bark and leaves and sap.

Despite the visible woody material in the picture above, the plants are growing well. This is about 2 months after the first one - they aren't growing as fast as usual because it's winter here. but they are definitely big enough to harvest leaves.

In my experience, small wood chunks improve soil friability in a manner that is better than small pebbles. So I don't have any problem with digging some of that in. Not a lot of it. But wood shavings (as in sawdust) really just adds generic organics to compost. Mostly carbs.

@daninthedirt, I don't think wood shavings or sawdust are just 'generic organics' or indeed just carbs. Both cellulose and lignin are not just carbs - especially lignin. It's tough, there are a very limited number of microbes (mostly fungi) that have the enzyme that breaks down lignin, and they operate in somewhat different temperature/moisture/air conditions than some others. There is considerable evidence out there that a lot of lignin doesn't get broken down, and _may_ constitute a good part of the humus materials in the right conditions. Just on the basis that lignin takes longer and often much longer to break down, it's likely that it will also help keep more organic materials in the soil longer. Mind, I think these comments apply also to leaves and other parts that have some lignin, just in different proportions.