Gardening Basics

How to Compost Fresh Wood Chips

What do you do with the leftover mulch from a recently removed tree? Follow these tips for mulching and composting fresh wood chips.

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Filed under: Mulching, Composting

If you have to remove a tree and have its stump ground up, you may be left wondering what to do with all the leftover wood chips mixed with dirt. The last thing you want to do is use this stuff directly in the garden as mulch.

That's because as the wood chips decay, they absorb vast amounts of nitrogen from the soil. As a result, there's little or no nitrogen left for the surrounding plants, and nitrogen is the most important element or nutrient required for plant growth.

So if you've got an out-of-the-way spot that's at least four feet away from any plants in your yard, you can create a makeshift compost pile and just let the stuff sit for as long as you like — at least six months or so. To speed up the process, add a few pounds of blood meal (which is essentially pure nitrogen) or add fresh grass clippings each time you mow.

You can put some wood chips in an existing compost pile, but do so sparingly. Ideally, it should make up no more than a quarter of the pile. It's a good idea to blend some sort of nitrogen-based-material into the pile, whether in the form of grass clippings, kitchen scraps or plant refuse from the garden. What you want to keep in mind is the carbon-to-nitrogen ratio, or the ratio of brown stuff to green stuff. Brown stuff is carbon, while green stuff is nitrogen. The ratio of the two should be relatively close to 50-50.

Keep the material slightly moist and well aerated. After all, the more often you turn the pile, and provided you supply the right moisture content — slightly damp, but not moist — the faster you get finished compost.

Another great spot to use the "green" wood chips is in pathways or other areas where you don't plan on planting anything. In this situation, it serves a twofold purpose: it's a great mulching material for starters, and because plants can't grow in the mix, it serves as an herbicide of sorts, preventing weeds from sprouting.