The dirt on bark chips

Stores are awash with wood and bark chips. Besides the usual supply available at nurseries and garden centers, clean white bags of chips show up in front of hardware stores and supermarkets.

The benefit of chips can be more than just cosmetic. Spread on top of the soil, chips break the impact of raindrops so soil stays in place. Chips also are an effective insulator, protecting shallow roots from the heat of summer sun. In keeping the soil cool, chips slow evaporation of water from the soil so it stays moist.


Some people spread a weed barrier of black plastic or landscape “fabric” over the ground and top it with a layer of chips. Used this way, chips are purely cosmetic. Besides depriving the soil of some of the benefits of chips, spreading chips over a permanent weed barrier leads to other problems.

For instance, the barrier gets messy if you ever want to move plants around. And it’s not that good at permanently thwarting weeds, which creep into the chip layer on top of the fabric.

Simply pile chips right on top of bare soil or, if weeds are present, on top of paper or newspaper mulch, which decomposes.


Some gardeners have the notion that chips sold in bags are superior to those made from locally chipped trees. One fear is termites will infest wood other than cedar, which is often the wood source for bagged chips. Termites feed on a variety of cellulose sources; a mulch of chips contributes insignificantly to the existing smorgasbord. Fungi also are picky in what they will attack.

To get a load of local wood chips, look in the Yellow Pages under “Tree Service,”