Garden Q&A: Tree roots and nightcrawlers

Yards made rough and uneven by tree roots and nightcrawlers were among the topics of recent e-mails received at the Extension office. Following are the gardeners’ questions, as they appeared in my computer’s inbox.

Q. Two summers ago, we had two maple trees removed because roots were encroaching too closely to the house foundation. The stumps were ground out, but the roots remain, and as you know, maple roots are sometimes on the surface. Will they ever rot? They show no signs of ever leaving, which would made the yard more even and easier to walk over, to say nothing of mowing. A.W., Lynchburg
A. It could be years before the tree roots rot and go away. You could dig them out or just wait for them to rot. Another option could be spreading mulch over the root-infested ground and planting a bed of flowers in it.

Q. When I was visiting my mom in Madison Heights this weekend, we found in her backyard numerous little piles of tiny muddy looking drops. We would find them all over her yard, sometimes with as many as four or five piles within a 6-inch square. We couldn’t see any holes like something was coming up out of the ground. What do you think these could be? She has numerous birds, squirrels, etc., because of the woods just outside the fence. V.C., Blacksburg
A. Your mom’s yard has an active population of nightcrawlers. These extra-large worms live in deep burrows and come up to feed on the surface at night. They leave behind small piles of soil, which can make walking on the lawn difficult. Many of the lawns in our area are just like your mom’s, and stores sell products for controlling nightcrawlers. They came to America with the early European colonists and have spread all over.

Q. I have a question regarding the use of pressure-treated wood where it will come in contact with food sources. What is the current thinking on using pressure-treated lumber for raised garden beds and/or to make compost bins? If trying to go organic, I know at one time it was ill-advised to use the pressure-treated lumber for fear the chemicals would leach into the soil. Then, I think I have seen a recent article that said the wood treatment is safer than in the past? I am finally preparing my new vegetable garden and will consider a soil-mounding technique for the planting areas, if it is still ill-advised to use pressure-treated wood. R.C., Lynchburg
A. Pressure-treated wood used to be treated with chromated copper arsenate. That wood treatment was replaced by a new, less toxic wood treatment in 2004. The treated wood now available is less likely to harm humans and the environment, though I am not sure if it is recommended for use in food gardens. A non-toxic alternative would be to build your raised beds and compost bins with woods that are naturally resistant to rot. Woods such as cedar, black locust and rough sawn oak boards are available locally.

Don Davis is an Extension Agent for the Virginia Cooperative Extension. He can be reached by calling 455-3740.