Pest control is top of mind for any farmer or gardener, whether they're growing in a greenhouse or the great outdoors. However, pesticides and insecticides are indiscriminately harsh and often wind up killing pollinators that help plants thrive. Luckily, you can always rely on nature's pesticide: beneficial insects.
How are Bugs Beneficial?
The importance of beneficial insects cannot be overstated. These helpful garden insects clear out pests without damaging the plants. It's a natural means to take care of your plants and get rid of pesky insects without harming pollinators or the plants themselves. In using beneficial insects, you can monitor the numbers of aphids, whiteflies, mealy bugs, leaf miners, and many other common kinds of greenhouse pests to ensure that your plants grow up strong and undisturbed.
What Bugs are Beneficial to Gardens?
Just like all species, garden insects are broken into two groups: generalists and specialists. A specialist bug will prey on one or a few different kinds of pests, while a generalist will eat a broader spectrum of prey, including other beneficial insects. When choosing a generalist species, it's important to keep an eye on their population size so they don't begin eating your other beneficial garden insects as well.
There are a few different kinds of beneficial insects that will be most helpful to your greenhouse environment. Check out the list of beneficial insects below to learn more about these helpful hunters!
10 Beneficial Insects for Greenhouses
Assassin Bugs: This class of predatory insect is extremely efficient at hunting and killing pests of all kinds, from leafhoppers to boll weevils. Common assassin bugs include the wheel bug and the cone-nosed bug (or kissing bug). Just be careful when handling — these guys bite!
Damsel Bugs: Nymphs and adults alike will feed on caterpillars, leafhoppers, thrips, aphids and more.
Ground Beetles: These iridescent beneficial insects take care of ground-bound pests like root maggots, slugs and cutworms, especially in their larval stage.
Hover Flies: Technically called Syrphid Flies, these yellow and black garden insects hunt down aphids as maggots and pollinate flowers as adults.
Lacewings: As larvae, these delicate insect specialists can devour dozens of aphids at a time. In adulthood, they tend to stick to pollen and nectar.
Lady Beetles: Voracious eaters of aphids, thrips, mites and more! The lady beetle, which grows into the ladybug, is the best bug you could ask for in your garden.
Minute Pirate Bugs: Small but mighty, these barely visible garden insects will help keep aphids, mites and thrips at bay.
Praying Mantises: These recognizable insects are most effective at pest control in their nymph stage, when they'll eat just about any bug in sight. They remain generalists throughout their lives, so make sure they aren't gobbling up all your lady beetles while hunting for caterpillars!
Rove Beetles: A predatory beetle that eats soil-dwelling pests like thrips and fungus gnats.
Spined Soldier Bugs: A type of predatory stink bug that eats caterpillars and grubs. It's a generalist, so make sure not to have too many.
Which Plants Attract Beneficial Garden Insects?
Having a garden or greenhouse full of delicious pests isn't always enough to attract the beneficial insects needed to combat them. Many beneficial insects also need the carbohydrates found in nectar and pollen in order to reproduce — others are only pest eaters in their larval state and grow into a nectar or pollen-based diet. The flowering plants listed below are excellent sources of nectar that will support your predatory insects and pollinators alike (and make your greenhouse or garden that much prettier).
Black-Eyed Susans (Rudbeckia)
Cosmos (Cosmos bipinnatus)
Dill (Anethum graveolens)
Laceflower (Ammi majus)
Meadowsweet (Spirea alba)
Mountain Mint (Pycnanthemum)
Prairie Coneflower (Ratibida pinnata)
Sunflowers (Helianthus annuus)
Yarrow (Achillea millefolium)
Buy Beneficial Insects for Your Greenhouse or Garden
Even if you do plant the flowers suggested above, the best way to guarantee that beneficial garden insects move into your greenhouse is to buy and release some yourself. Bootstrap Farmer has partnered with ARBICO-Organics to provide you with all the beneficial insects you need for natural pest control and pollination. Check out their wide selection today or view the rest of Bootstrap Farmer's available farm nutrients to create a thriving ecosystem in your greenhouse or high-tunnel.
Light deprivation is a growing technique often used to encourage or discourage flowering in plants outside their regular seasonal schedule. Using blackout tarps to simulate the seasons' changing, growers can take advantage of up to three harvests: early summer, late summer, and winter.