Four Tips for Attracting Beneficial Insects to Your Garden

Bugs With Benefits Are a Green Thumb's Best Friend

A ladybug eating aphids.
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As a gardener, there's nothing more frustrating than watching your prized vegetable crop being devoured by insect pests. A couple of hornworms can level a row of tomatoes overnight. Fortunately, every pest has a predator and you can use that natural food chain to your advantage.

Attracting beneficial insects to your garden can keep pesky pests at bay but what exactly is a beneficial insect? Simply put, it's an insect or arthropod that helps keep plants healthy and thriving. Some insects eat pests such as aphids and beetles. Some form parasitic relationships with pests, eventually killing their hosts; while others help pollinate crops to ensure a good harvest. Ideally, you should try to attract all three kinds of beneficial insects to your garden: predators, parasitoids, and pollinators. These four tips will arm you with the winning strategy you'll need to win the battle of the bugs.

01
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Use Pesticides Wisely

Spraying pesticides.
Getty Images/Goydenko Liudmila

When you find your broccoli smothered in aphids or your squash awash in beetles, your first instinct might be to reach for a chemical pesticide. Don't! Broad-spectrum pesticides eliminate the good guys just as effectively as they wipe out the bad guys. Remember: You're trying to attract more insects to your garden, not kill them all. As long as they've got a food supply, beneficial insects will stay put once they've arrived. Don't send them packing by spraying toxic chemicals.

Don't be daunted if when you begin your attempts to attract beneficial insects, you find the pest population skyrockets as well. Be patient. The good bugs need time to locate their living smorgasbord. For instance, once lady beetles set their sights on havoc-wreaking aphids as a food source, they'll mate, lay eggs, and soon, they'll be picking your broccoli clean of pests.

Choose and Use Pesticides Carefully

While chemical controls must be used with caution, sometimes when a serious outbreak occurs, you might need to use a pesticide to get it under control quickly. If using a pesticide can't be avoided, at least you can limit the negative impact on beneficial insects by selecting the appropriate products and using them carefully.

Whenever possible, choose a pesticide that targets the pest, rather than a broad-spectrum insecticide that cuts down nearly everything in its path. Also, be sure to choose products that degrade quickly and have a shorter residual impact on the insect life cycle. In most cases, botanical pesticides kill fewer beneficial insects than longer-lasting synthetic pesticides. Horticultural oils, insecticidal soaps, and botanical insecticides (such as products derived from pyrethrins or neem) will get your pest problem under control without causing long-term damage to your beneficial insect population.

02
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Plant an Insectary

Soldier beetle on carrot flowers.
Getty Images/Stavros Markopoulos

An insectary is a garden plot just for insects. Insectaries can be separate landscape beds planted in close proximity to your garden, or several small plantings interspersed among the veggies.

Insectary 101

Choosing the right variety of plants will attract beneficial bugs to your insectary neighborhood. Start with some early bloomers to attract beneficial insects at the start of the season, even before your crops are being pestered by pests. Many important beneficial insects, such as hoverflies and lacewings, feed on pollen and nectar as adults. By providing flowers early in the season, you'll be inviting these insects in time to unleash their predatory offspring on aphids and mites.

Your insectary should include plants of varying heights. Low-growing herbs such as thyme and oregano give ground beetles a place to hide. Taller flowers, such as daisies or cosmos, beckon to hoverflies and parasitic wasps looking for nectar. Praying mantids are big pest eaters that like to hide between plants that give good cover.

Umbels and composite flowers provide the most attractive food sources for a variety of beneficial insects. Umbels are characterized by tiny clustered flowers that offer exposed nectar and pollen to smaller pollinators like parasitic wasps. This group includes yarrow, dill, fennel, and wild carrots. Composite flowers including garden favorites such as zinnias and sunflowers, attract larger pollinators like robber flies and predatory wasps.

Five Best Plant Families for Beneficial Insects

These five plant families will pack the most punch when it comes to attracting beneficial insects to your garden:

  • Aster Family (Asteraceae): ageratums, asters, chrysanthemums, cosmos, dahlias, marigolds, and zinnias
  • Carrot family (Apiaceae): Angelica, caraway, carrot, celery, chervil, cowbane, cumin, fennel, parsley, parsnip, Queen Anne’s lace
  • Legume family (Fabaceae): green bean, lima bean, scarlet runner bean, chickpea, fenugreek, lentil, lupine, pagoda tree, smoke tree, soybean, tamarind, wisteria
  • Mustard family (Brassicaceae): arugula, bok choy, broccoli, cabbage, cauliflower, collard, kale, kohlrabi, rutabaga, turnip, horseradish, rocket, shepherd's purse, watercress, white mustard, wild radish
  • Verbena family (Verbenaceae): Verbena (also known as vervain) family, includes 31 genera and nearly 920 species including lemon verbena, blue vervain, lollipop, meteor shower, Greystone Daphne, homestead purple, and Texas rose.
03
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Provide a Water Source

Ladybug in a puddle.
Getty Images/Zsófia Peto/EyeEm

If you use a sprinkler to water your garden, the puddles that form should suffice to keep your bug population hydrated. Between waterings (or if you use a drip irrigation system), the insects will require another source of water. You can make a simple watering hole using a saucer and some rocks. Be sure to replenish it on dry days. Remember, most beneficial insects have wings. If water isn't close by, they'll take off in search of what they need. If you want them to keep working in your garden, don't let their water source dry up.

04
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Give the Ground Dwellers Some Cover

Ground beetle.

Getty Images/Santiago Urquijo

Some beneficial insects keep low to the ground, searching for soil-dwelling pests. Ground beetles, for example, rarely climb foliage looking something to eat; instead, they patrol the soil at night, munching on slugs and cutworms. During the day, these nocturnal minibeasts need shelter from the heat and sunlight.

Keeping your garden beds mulched allows ground beetles and other earthbound insects find a safe haven during the hottest daytime hours. Mulch also keeps the soil moist and prevents beneficial bugs from losing hydration. Stepping stones are another good source of friendly bug cover. Many insects thrive under flat surfaces and stones when they aren't hunting pests.

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