How to keep your garden pest-free without killing pollinators. Tips from a master gardener.

How many times have you sprayed your entire lawn or garden with chemicals — even organic ones — in the past few years?

To Gretel Anspach, a master gardener, one time is too many.

“The concept of, ‘It’s June, so I’m gonna spread pesticides on my lawn just because it’s June’ is really horrible for the environment,” Anspach said. “We get very glib about it. We forget these really are poisons.”

Anspach is a former president of the Massachusetts Master Gardener Association, an independent organization that educates communities on gardening.

The longtime gardener and expert in integrated pest management shared her tips with Boston.com.

What (and what not) to use

According to Anspach, there are three ways of killing a plant: digging it up, clipping its leaves until it starves, and spraying it with chemicals.

She urged against the wholesale use of any chemicals, pesticides, or fertilizers — even those labeled organic. The overuse of fertilizers poses numerous threats to the environment, including water pollution and algal bloom, Anspach said.

On top of these harmful effects, chemicals can kill plants, pollinators, and animals that are necessary to food chains, warping ecosystems.

“Without the insects and birds they rely on, some plants would no longer exist,” Anspach said. “Once you start eroding the food chain that way, we don’t know what’s going to be left.”

Herbicides and insecticides can threaten backyard ecosystems, Anspach said, but using them in moderation can be safe and effective.

Instead of spraying entire lawns or gardens, she said, gardeners should use them in a “deliberate, targeted way.”

Herbicides and insecticides

For herbicides, Anspach prescribed a one-time use on a targeted area. After the targeted plants have been killed, re-plant your desired ones. For pesticides, she suggested a longer process that starts with a difficult step: simply waiting it out.

“When we leave nature alone, it has a tendency to balance itself out,” she said.

Anspach provided an example using corn, aphids, and ladybugs. Aphids — small insects that can cause significant damage — may take over a corn crop, but they are a natural prey of ladybugs.

When corn plants are bitten by aphids, Anspach said, they release a chemical that ladybugs process as “a giant meal waiting to happen,” she said. Ladybugs eat the aphids, saving the corn.

If a natural remedy like this one doesn’t come along after some time, Anspach suggested using “mechanical means” to remove pests — even if it means picking critters off your plants using your fingers.

If that’s unsuccessful, she gave the go-ahead to use a targeted insecticide: one that will kill only certain pests instead of decimating everything in its vicinity, including pollinators.

Natural remedies

When it comes to natural remedies, Anspach said there are two types: fertilizers in disguise and critter-attractants that work as herbicides.

Fertilizers in disguise include commonly composted items like banana peels and coffee grounds. Rich in potassium, banana peels work as a potassium-based fertilizer; coffee grounds are the same, but with nitrogen.

Attractants — like a bowl of yeast, water, and sugar — can be used to draw critters like fruit flies away from precious plants. This is just as effective as killing the insects and better for the food chain, Anspach said.

What else can we do?

In most cases, Anspach said, we should be a little softer on our expectations for perfectly groomed grass and clean, flower-less lawns. And, when searching for solutions, chemicals shouldn’t be our default response.

“This idea that a lawn should be just grass and not have … all of these beautiful flowers in it, I don’t get it,” she said. “Dig ’em up. You don’t need to poison them.”

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