Whether you’ve chopped down a tree in your yard and chipped it yourself or have leftover chips after mulching, composting can be a great solution. But if you’ve ever tried to compost wood chips, particularly ones you’ve bought for mulching, you might be dismayed by how slow they are to decompose.
How Long does it Take for Wood Chips to Decompose?
The time it takes to for wood chips to decompose will depend on their size and whether they’re treated or not (some chips may have paint, creosote, or other chemicals on them from previous uses).
Untreated woodchips, as long as they’re broken up finely enough, shouldn’t take longer than 5-6 months to decompose in a composting pile. This is assuming optimum conditions: the pile is hot, the nitrogen’s just right, the weather’s not too cold, and you’re turning the pile often enough.
If you’re looking to keep the wood chips out of the compost bin and instead use wood chips as a soil amendment, then the process will take much longer, as long as five years or possibly more.
How do You Make Wood Chips Compost Faster?
To compost wood chips fast, you should ensure the chips are as small as possible, check the carbon-nitrogen ratio of your compost heap is correct, and turn the heap often. Wood chips are carbon-rich, so you might need to up the nitrogen content by adding grass clippings, fruit and vegetable scraps, or even leftover coffee grounds to your compost pile.
Let’s take a look at these tips in a bit more detail:
1. Make Your Wood Chips Smaller
Like large branches of wood break down slower than smaller branches, larger wood chips decompose slower than smaller ones. If your wood chips are taking too long to break down, they are likely too big; chopping them down to a smaller size means they will decompose much faster.
If you don’t want to pay a tree surgeon and can’t buy, borrow, or rent a wood chipper from, we recommend checking out the rest of the tips. However, if your chips are too large, they will still be slow to compost even if you do everything else right.
2. Get the Nitrogen Ratio Right
If you’re looking to throw the wood chips onto your compost pile, the best way to get them to decompose faster is to introduce the right amount of nitrogen-rich material to get the compost heap hot.
You can throw on a ready-made fertilizer or composting agent which will add nitrogen sources, but we like to do things the old-fashioned way around here. So you’re looking to add organic and natural sources that are full of nitrogen content.
Lawn clippings, coffee grounds, fruit and vegetable kitchen scraps, fresh flowers, and leaves should be on top of your list. They’re bursting with the ingredients you need to get those microbes kickstarted and begin composting wood chips.
Don’t forget, though, that you shouldn’t overdo the nitrogen source. You might think that because you have a whole pile of wood chips, you should add a whole pile of nitrogen material and get the process done faster, but it doesn’t work that way!
Overdoing the nitrogen will mean your optimum bacteria levels will get right out of balance, and you’ll end up with a stinky mess that’s less compost, more swamp. Keep the nitrogen ratio at only 20 percent of your pile; the other 80% should be your wood chips, cardboard, tree bark, and other carbon-rich materials. Getting this ratio right will ensure you have an efficient compost pile.
3. Turn Your Compost Pile More Often
Once the hot compost has done its work in a certain area of the pile, the decomposition process will slow down if you don’t keep the microbes happy with more work. To do this, you need to turn the pile. The benefits are many: you put oxygen into every layer of the pile (which boosts decomposition), you improve drainage, and you spread the active microbes throughout the pile.
You should be turning once every three weeks or so in the summer, but less often in the winter, because you don’t want to let too much heat escape. Depending on the pile’s height and size, you might want to invest in a compost turning tool or aerator.
4. Add Nitrogen-Rich Ingredients
The composting process is a delicate one that needs a whole pile of ingredients, finely balanced for optimum effect. But there are ways to up the speed of composting wood chips if time is of the essence.
Fertilizer, as mentioned earlier, can be a great way to top up your nitrogen levels. This is especially important if you’re composting in the wintertime when everything slows down. You’re unlikely to have much in the way of grass clippings or green branches from plants if you’re not tending to the garden as much.
Commercial fertilizer is also an important source of ammonium sulfate, which adds nitrogen but at the same time works to lower the soil pH of your compost. If the soil pH is too high, it’s too alkaline, so balance it out by shifting it to a slightly more acidic place on the pH scale.
Another kind of compound using ammonia is ammonium nitrate. It’s a rapid way of introducing nitrogen into compost piles, so again if you need to compost wood chips fast, then you might want to think of kickstarting the decomposition process.
Another thing you could try is to add some horse manure. Sounds gross, but horses feed on huge amounts of grass and other organic matter every day, and as a result, their gut microbes are a perfect source of nitrogen. Your local stables will be only too happy to have you take some off their hands!
How Do You Make Compost out of Wood Chips?
If you already have a compost pile, introducing woodchips is the same as introducing any other high-carbon material, including wood, branches, bark, dead leaves, or cardboard. Treat the compost pile as you always have, and you’ll be fine.
But if you’re looking to turn a wood chip pile into a compost pile, or you don’t otherwise have a compost pile in your garden, it’s a great way to get into the composting game. First, put a layer of wood chips on some bare earth. Then add some grass clippings, kitchen waste (organic food waste), and other nitrogen-rich materials.
Then, more wood chips. Maybe on top of this, add some manure before another layer of wood chips. As you can see, you’re layering the pile, but you’re not adding too much nitrogen. Depending on the size of your compost pile, you might need more or fewer layers, but keeping that 4:1 carbon to nitrogen balance is key.
Don’t forget to turn the pile! Wood chip compost has a great advantage in that the shape of a wood chip allows for plenty of oxygen, but you still need to actively get the microbes working all over the pile for full decomposition.
Is It Better To Compost or Mulch Wood Chips?
Composting isn’t the only choice you have when you have a pile of wood chips to deal with. Mulching is the process of spreading bark, leaves, wood chips, and other carbon-rich material over soil and around plants. The leaf mold produced is a great source of nutrients that the soil needs.
There are several reasons gardeners and landscapists choose to use mulch. It looks great in the garden and is highly efficient at maintaining the soil’s moisture level around a plant, preventing it from submitting to wintertime frost. Mulch can also stop weeds appearing around plants, meaning there’s less work for the gardener.
How can I Make Mulch Decompose Faster?
Mulching means that the soil under the wood chips uses a lot of the nitrogen from the soil. It means that if you’re applying piles of wood chip mulch around your plants, you’ll need to replace the nitrogen in the soil that will go toward breaking the wood chips down. The soil organisms won’t be able to keep up with the decomposition of the wood chips at the rate necessary.
This is where fertilizer is vital; without it, you’ll end up with poor quality soil and wood chips that simply aren’t decomposing at the rate they’re supposed to, which makes the whole process doubly pointless.
How To Use Your Finished Wood Chip Compost
Now you’ve got a good amount of high quality, wood chip compost, use this around your garden. Even if your compost pile hasn’t fully broken down all of the wood chips, if its otherwise finished compost, you can still use it.
Wood chip compost can still help with water drainage, preventing pests, weed growth and the effects of frost on and around your plants. Whatever you decide to do with your wood chips, you’re recycling organic material, which is always important!