Every evening, we see two lizards clinging to the wall beneath our porchlight. In the morning, there is a pile of wings and other insect parts on the ground. Are the lizards hunting by the light? Are they dangerous to our children?

It sounds like you have Mediterranean house geckos (Hemidactylus turcicus) on your home pest-management team. That’s a good thing. According to the Tucson Herpetological Society, these geckos are the only lizards you are likely to find clinging to walls to hunt by night in Arizona. Their diets consist mostly of insects, including moths and grasshoppers drawn to your porchlight. Although Mediterranean house geckos are not endemic to the United States—they’re native range spans from the Mediterranean region into India—they are not considered “invasive” because they have not been observed colonizing habitats outside of human development. They are quite shy and lack venom, so are not a threat to people or our pets. If you’d rather not have them leaving their dinner scraps on your doormat, turn off your porchlight at night to stop attracting their prey.

A weed has very quickly covered my entire backyard. It forms big mats on the surface of the ground but makes these sprays of little white flowers that resemble baby’s breath, and the seeds stick to my dog’s fur.  What is it, and how do I get rid of it?

Sounds like your yard has been overtaken by spiderling, a spreading, warm-season annual weed that spreads by seed. Don’t bother spraying it with an herbicide at this point; once it has started producing seeds (and sticking them to your dog’s fur for dispersal), chemical applications will not get rid of the problem. Use a garden hoe to sever the green mat from the taproot, bag up the plant and send it to the landfill to keep from spreading more seeds in your yard. One spiderling can cover an area 6 feet in diameter, so it is remarkably fast work and satisfying once you start chopping and bagging. Prevent the unwelcome plants from taking over next year by hoeing them as soon as they germinate in May or June, or have a licensed applicator use a reemergence herbicide to manage them chemically next spring.

After three months, the yard waste and kitchen scraps we put into our compost bin haven’t really changed, except for drying out and shriveling. What are we doing wrong?

The microscopic fungi and bacteria need water to turn yard and kitchen waste into black garden gold. As a general rule, the materials in your compost pile should have the moisture content of a rung-out wet sponge. In other words, damp but not saturated. If your pile needs to be watered more often than every three days or so, you may need to help it conserve moisture by covering it with a tarp or chopping the materials into smaller pieces. Remember to turn the compost every week or so to make sure there is enough oxygen to keep it from getting waterlogged and smelly.