Wood Chips and Stump Grindings

If you have the space, a wonderful method to suppress weeds and build soil is using wood chips. Call your local tree service to find out if they will drop off chips, or use Chipdrop. This website matches homeowners who want chips or logs, with tree companies that need a place to get rid of them. Chips are free and it's a great way to utilize a "waste product."

I've been using wood chips in my garden for over 15 years and have yet to see any downside. I started out using chips in garden paths because they looked great and made a dry surface to walk on. I noticed they were breaking down pretty quickly into a light and fluffy matter, which I decided to dig out of the paths and place in my beds. Now I practice path-mining every growing season to renew existing beds or build up new ones. If you have chips delivered and need to get them moved out of the way quickly, but you don't want to put them directly into beds, this is a great method.

If you have a sizable area to dedicate to a chip pile, accept large loads, then let them sit. New piles will steam gently on cold mornings from microbial activity. This phase won't last long since your chip pile consists mostly of carbon materials, lacking the nitrogen- contributing materials of a typical compost pile. Fungi will soon take over, and earthworms, sow bugs, and innumerable other invertebrates will join them. It's all good. The only thing I would caution against is moving chips when fungal spores are present, because breathing them in could cause respiratory problems. If you start shoveling and notice clouds of what looks like steam, but isn't hot, wait a few days then try again.

If you're lucky you will receive a portion of stump grindings in your chips. Tree companies use a special machine to grind stumps which results in a much finer material, much like sawdust. It breaks down more quickly than chips. The photos below show a pocket of grindings I discovered in a pile after leaving it for several years.

At this point it almost resembles soil. It made a great mulch for my Asian pear.

Chips left for long enough eventually break down, but in dry climates it might take a very long time. Raking out a depression in the top to channel rainwater into the pile will help. However, you can use chips at any stage of decay. They won't rob your plants of nitrogen as long as you don't mix them into the soil. I've never had problems with chips, but because there is immense variability from site to site, you might want to experiment in a small area before going whole hog.

Without wood chips I definitely wouldn't have the garden I have today. They have been an incredible help in adding organic content to my heavy clay soil, and releasing its fertility. So today I am thankful for wood chips.