Attracting Beneficial Insects To Your Garden

If you are making the switch to organic gardening, you may be concerned about losing plants to insect pests. In the short run, this is likely to occur. However, established organic gardens typically lose fewer plants to insect pests than conventional gardens.

This is because pesticides intended to kill insect pests also kill beneficial insects. When a garden has a healthy population of beneficial insects, they keep the population of insect pests under control, reducing the chances that any one species will get out of control.

You can sit back and wait. If there are harmful insects in your garden, the beneficial insects that prey on them will turn up sooner or later to take care of them now that they are no longer being poisoned. However, you can also take measures to speed the process up (hopefully reducing plant loss during your transition to organic gardening) by choosing plants and designing your garden in a way that will attract beneficial insects.

Note, for my own convenience, I'm going to be biologically inaccurate and lump spiders, earthworms, and other insect-like beneficial non-insects in with insects for the duration of this hub.

The four main types of beneficial insect you'll want to attract to your garden are:

• Predatory Insects
• Parasitic Insects
• Pollinators
• Decomposers

Choosing Plants

When choosing plants, the most important thing to remember is that diversity breeds diversity. The best way to maximize insect diversity is to have a lot of different kinds of plants.

Many cultivated flowers are bred mainly to be beautiful to human eyes and have lost their attractiveness to insects. Your best bets for insect gardens are mainly wildflowers and flowering herbs.

A healthy population of pollinators can increase the productivity of your garden by 30%. Studies have shown that pollinators such as the honeybee and the many species of native bees are most attracted to gardens that have at least a few different types of flowers blooming throughout the whole growing season. Bees also like gardens with relatively large plantings that have 10 or more different attractive species planted relatively close together in large swathes or groupings.

Following a voracious larval stage, many predatory insects also live mainly on nectar and pollen as adults, including many types of lacewings, wasps,and predatory flies such as hoverflies and tachinid flies, so a diverse selection of flowering trees, shrubs, and plants is important to atract them as well. Generalized predators such as praying mantises, which eat both harmful and beneficial insects, are attracted to plants with high levels of insect activity, including many flowering plants. I recently counted no less than six big mantises waiting patiently for a snack among my mother's masses of Russian sage and catmint.

One of the very best insect-attracting plants is clover. Although in recent decades, clover has been considered a weed, in the past it was routinely included in seed mixes for lawns and clover lawns are currently experiencing a revival. Among the many beneficial insects clover attracts are damsel bugs, big-eyed bugs, ground beetles, bees, and many types of parasitic wasp.

Other great insect-attracters include members of the carrot family such as dill, Queen Anne's Lace, and Angelica, scented geraniums, tansy, aster, butterfly weed (Asclepias tuberosa), marigolds, bergamot, daisies, coneflowers, marguerites, sunflowers, thymes, and sages. Weeds such as dandelion and mustard are also popular, as are some agricultual crops, such as alfalfa.

Just as important as choosing the right plants, is providing a place for beneficial insects to call home.

Insects prefer a slightly sloppy garden to a perfectly manicured one. Many beneficial insects overwinter in leaf litter or rotting wood, so creating a small brush pile in one corner of your yard will give them a hand.

Mulches of wood chips or other organic matter are another way to give many beneficial insects a home, and they also protect soil against early frosts that can kill earthworms before they have time to dig down for the winter. Be careful not to pile mulch too thickly under trees or too close to their trunks - this can harm the tree. Leaving some bare ground will also benefit ground-dwelling native bees and wasps, while sandy soil protected from rain is favored by the ferocious larvae of the ant lion.

Dense plantings are attractive to many insect species because they protect against wind and rain. Hedgerows containing a diverse mix of shrubs, flowers, grasses, and the occasional tree have long been popular with farmers in Europe and New England, and are experiencing a revival in other parts of America as well, especially among organic farmers and practicers of permaculture and biointensive integrated pest management techniques such as farmscaping. Ground covers can help maintain proper temperatures and humidity levels for some species, such as aphid midges and predatory decollate snails.

Other beneficial insects, including predatory ground beetles, like to hide under stones, bricks, or fallen logs, or in compost piles.

A few beneficial insects, especially damselflies and dragonflies, are semi-aquatic. A small water garden will attract them, and also provide a good source of water for other insects and birds.