Ask the Gardener: Can you reuse container soil?

Ask the Expert
Tired of bagging leaves for curbside pickup? Start a compost pile. Adobe Stock

What to do this week: It’s a busy time for planting and cleaning up. Tired of bagging leaves for curbside pickup? Start a compost pile. Collect leaves in a corner out of sight, alternating this brown stuff with layers of green stuff, such as mowed grass and disease-free perennial and vegetable debris when you cut down your garden. When the pile reaches 4 by 4 feet, start another one nearby. You can add pulled weeds before they go to seed, but not woody branches, invasive vines, bamboo, or any kitchen scraps containing fats or proteins. Coffee grounds and potato peels are great. I encircle the pile with chicken wire to keep it from blowing around. It’s so much easier than bagging backyard refuse. Worms and other soil critters eventually turn it into compost, a.k.a. “black gold,’’ a free soil amendment to add back to the garden. This is how forests recycle fallen leaves into organic fertilizer for the trees that produced them. Why haul it away? You can actually let leaves remain where they fall in woodlands and shrub borders. But, unfortunately, they will smother grass, so you have to remove them from lawns.


Q. Can I reuse container soil or should I change it? How should we sterilize a container with blight?

W.K., Yarmouth Port

A. Throw away the container soil that grew blighted plants, but dump your uncontaminated growing mix in the compost pile, where it will be rejuvenated for future use by the billions of soil organisms living there. Immerse all empty pots in a solution of 10 percent bleach and 90 percent water for 10 minutes to sterilize them. Then wash them with dish detergent, scrubbing the clay ones with a wire brush or steel wool. Let them dry in the sun.


Q. Our backyard is surrounded by a hedge of tall arborvitae, however, there is one area with brown spots. We have periodically cut them back to try to save them, so they are now shorter and misshapen. Our neighbors told us there used to be a tree in that spot (unknown variety). What can we do to treat the soil and ensure that if we plant new arborvitae they will grow?

B.G., Weymouth

A. I, too, have a “death spot’’ in my yard, where three successive trees I planted have died. Maybe it is cursed by the soul of the old apple tree the previous owner cut down (or chemicals they used to break down the roots?). But the problem with arborvitae hedges is that they usually don’t grow evenly, and they can’t be pruned into a hedge-shaped privet like other willing-to-please shrubs. That’s because arborvitae are actually cone-shaped trees, not shrubs. Landscapers like them because they are tall, narrow, evergreen, and fast-growing. But I think they are being mislabeled as hedge plants. Give up on the idea of symmetry. I would plant a few new arborvitaes of the exact same variety (there are several kinds) in front of the bad area and in a couple of other spots to turn your hedge into a grove of arborvitae. This will occupy more space, but if individuals sicken or die or even just falter, it won’t ruin the effect. You can plant now if you water your evergreens weekly so they can store up moisture for protection against winter winds, or wait until April.

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