What’s the least toxic way to get rid of weeds in my gravel driveway? I’d rather not use harsh chemicals, but there are too many to pull them up by hand. -BJ

Because you’re weeding a gravel area, you have the advantage of not having to worry about killing desirable grasses or garden plants, and less of the product will come into contact with garden soil. Nevertheless, everything we do in the garden has some impact on the environment, so you’re wise to minimize the use of chemicals. Here are some ideas:

• Barriers: The next time you replenish the gravel in your driveway, consider putting down landscape fabric or plastic first, to prevent weeds from sprouting through the gravel. You can also put barriers around the edges, to help keep weeds and grasses from creeping out of your lawn.
• Heat: To kill weeds using heat, carefully pour boiling water directly on the plant. Or, you could try using a paint stripping heat gun to crisp the weeds in your gravel.
• Vinegar or Soap: Vinegar and herbicidal soaps kill (by drying out) all vegetation in their paths, but they are thought to kill beneficial microbes and sterilize soil. This is less of an issue in your gravel drive, although you should consider that some of the product will run off into drainage areas.
• Herbicides: If you resort to organic or chemical herbicides to control weeds in your drive, you can minimize the environmental impact by carefully painting the liquid directly on the leaves, or by using a shield to target the weeds.