What are your recommendations for keeping a garden quenched without wasting water?
—Rachel Carter, Ludlow, VT

You can forget juicy tomatoes this summer if you don’t give your plants enough to drink, but the fact is, most people water their gardens wrong. Each year, from May to September, water use nearly doubles in parts of the country (mostly for keeping our backyards green), and about half of it is wasted through evaporation, runoff, and overwatering.

You may not need to water at all if you use native plants, because they’re already adapted to a region’s climate. But if you are going to water, the first thing to do is assess how much your yard and garden really need, says Bernd Leinauer, a turfgrass specialist for New Mexico State University’s extension service. He suggests contacting your local university extension office for advice, since most people use too much water.

Next, audit your sprinklers, which are often inefficient. “They throw water in the air, and you hope that it eventually lands where you want it,” Leinauer says. “It often doesn’t.” (For easy-to-follow instructions on how to do an irrigation audit, visit Austin’s site.)

Furthermore, using a drip irrigation system instead of sprinklers can cut your water use by a third or more, while other systems, including bubblers, microsprayers, and soaker hoses, work well for watering specific trees or plantings in a small area. Drip irrigation uses a grid system of hoses buried three to four inches deep, with holes every 12 inches, so water is delivered slowly and directly to the plants at root level, where they can use it most efficiently.

Your plants will be happier and healthier, too; watering at the roots ensures the plants receive consistent moisture and makes them less susceptible to disease. Drip irrigation also keeps topsoil intact and nutrients in place so they can do their job. In the end you’ll have more time to lie back in your hammock and enjoy the fruits of your labor.

Originally printed as Starre’s “Green Guru” column for Audubon Magazine.

The butterflies are migrating! I have noticed the delicate orange wonders flit joyfully through my neighborhood from one purple butterfly bush to the next for about 2 weeks now. They float along the sidewalks, the Potomac, and through our backyards. Today I counted about 13 of them float by my office window. The butterfly migration marks the end of summer, but no one is quite sure just how they do it.

I remember the first time I noticed the migration. I was standing in the parking lot of an apartment complex I was living in and it seemed that several butterflies were traveling in the same general direction, one after another, like on a pathway. I immediately started to research what I witnessed to find an explanation.

It appears that monarch butterflies travel from Canada all the way to Mexico every year in order to winter in a warmer climate. The longest recorded distance for one tagged flutterby was about 2, 879 miles (4, 634 kilometers). Once they reach Mexico, they gather on cypress trees, one layer upon the next, creating an incubated space for the butterflies at the center. This is how some of them make it through the winter in order to reproduce the following year. A single butterfly of the Methuselah generation, a special generation of the Monarch that can live 7 to 8 months rather than the normal 5 to 6 weeks, will make the journey south for the winter to hibernate. When they make the return journey north in the spring, this generation will make it only so far before they lay eggs and die; the subsequent generations will continue north along the path to Canada, but it will take several generations of shorter lived butterflies to make it there. Pretty fascinating!

Pesticides, deforestation, and general human expansion threaten populations. This miraculous event is one that we are just barely aware of as we rush through our daily routines, but we can be more involved. You can volunteer/support groups that monitor and tag the butterflies; plant appropriate plants, such as milkweed, for them to eat, lay eggs on, or take refuge in; get your kids involved by creating an educational project around conservation and understanding what we know about these creatures; educate yourself; refrain from spraying your gardens and lawns with pesticides. Just as I was writing this piece, I counted 6 more butterflies pass by my window!