Q: I live in southern California about five minutes from downtown Los Angeles where the soil is mainly clay. In our backyard we have an apricot, lemon, and lime tree and are planning to add a ginkgo and camphor. We’d like to put down gravel or sand because we have three dogs and don’t want sod. Can you give me some guidance on environmentally friendly gravel or sand that would be fine for the trees and puppies? —Sofia Sunseri via e-mail
A: All new or “virgin” sand and gravel requires excavation and transportation, both of which have negative environmental impacts. Some companies do grind up concrete demolition waste to use as base material for highway construction. Although energy is required for the crushing process, it’s a more environmentally friendly choice. However, I don’t know how paw-friendly that material might be.
As an alternative, I suggest mulch made from brush and green waste. In the Los Angeles area, it’s available—free of charge—from the Los Angeles City Bureau of Sanitation and is made from the green waste that residents deposit in their “green” bins. With continual use, the mulch will slowly break down to add nutrients and organic matter to your clay soil, ultimately making it more life supporting for your trees. And it will be easier on your pets’ paws.
Julia Scofield Russell is founder and director of the Eco-Hom Network and the Eco-Home demonstration home for sustainable urban living in Los Angeles.