Gardening inside a greenhouse can provide your plants with a certain amount of protection, but pests can still become an issue. Because your plants are all housed together in one small, closely contained area it’s incredibly important to prevent an infestation before it affects your entire garden. Should pests still find their way in be sure to eliminate them immediately before they can get out of hand and spread to the rest of your garden.
Pests to Watch Out For
There are many different insects, bugs, rodents, and animals you’ll want to keep out of your greenhouse. Aphids, gnats, and whiteflies are some of the most common insects but you may also see pill bugs, sow bugs, mealybugs, scale, mites, or thrips. Keep a close eye on the underside of your plant’s leaves and the top layer of their soil to make sure nothing is taking up residence. Checking for bugs on a regular basis will ensure you can catch an infestation before it can even get started.
Tiny insects aren’t the only creepy crawlies you need to watch for. Snails, slugs, and caterpillars would love to chow down on your plant’s leaves as well. Even if your greenhouse is sealed, these guys can sneak in under the lips of pots or inside the drainage holes. Mice, groundhogs, and other small rodents can become an issue if your greenhouse has any little cracks or holes they can slip through.
Preventing pests from getting into your greenhouse is by far the easiest form of pest control. Once they’re in, getting rid of them can sometimes be a hassle. One of the best means of prevention is to install a screen on every opening, including all windows, doors, and air vents.
Screens prevents pests from wandering inside on their own, but it won’t stop them from sneaking in on the items you bring in to your greenhouse. Keep pests out by washing off any gardening tools you bring in, checking new plants for any bugs, keeping your pets out, and if you want to be extra careful, changing your shoes before you enter your greenhouse. Make sure you don’t have any insect-ridden plants growing around your greenhouse as this will make it even easier for these pests to find their way inside.
Greenhouses are often warm and moist, which can be a great atmosphere to grow your plants in but can also be a very attractive environment for certain insects. Overly moist soil is the perfect breeding ground for gnats and pill bugs. You can cover the top layer of soil with small pebbles so gnats can’t lay eggs or hatch in the soil. You can also use self-watering planters that will water the roots from below so the top layer of soil stays dry.
Some of these nasty pests have natural enemies that will protect your plants. Attract ladybugs and lacewings into your greenhouse so they will feed on the insects that are harmful to your plants, such as aphids and mites. These beneficial bugs consume pollen and nectar so plant pollinating flowers such as daisies, yarrow, dill, or Queen Anne’s lace to lure them in. You can also purchase ladybugs and lacewings in some garden centers or online if you’re having trouble attracting them naturally.
Physical Pest Control Methods
If pests have already taken up residence in your greenhouse, manually removing them should be your first step. You can handpick caterpillars, slugs, and snails off your plants or scrape scale off if you see them attached to the underside of leaves.
Aphids, mites, mealybugs, and whiteflies can usually be sprayed or washed off your plants with a hose or spray bottle. This process can be long and tiresome, and may need to be repeated every couple of days until the pests have disappeared completely, but it’s totally safe and natural, using no harsh chemicals or pesticides. You can even use a little bit of dish soap to help kill the bugs and you won’t be harming your plants or putting toxic chemicals into your soil.
Sticky traps are very handy for any flying pests such as whiteflies, gnats, and winged aphids. Traps will not only help you to remove the pests that are present but they can also act as a monitoring system that will indicate the insect’s presence before a full blown infestation takes place.
If you have a rodent problem you could simply set up a few mouse traps but if you can’t bear to kill mice or other rodents there are a couple other options that are a little more humane. You can deter rodents and other pests from coming around with an ultrasonic pest repeller. Or, as another non-fatal option, use a live animal catch and release cage.
Insecticidal Soaps & Sprays
If your infestation has gone beyond the prevention and physical pest control stages you may need to try an insecticidal soap or spray. Insecticides will be much more effective at killing pests such as aphids, mealybugs, mites, whiteflies, and thrips but they’ll certainly be more expensive than simply washing these bugs off with water. Insecticides may harm fish or other insects so if you’re using an aquaponics system or if you have beneficial bugs in your greenhouse you’ll need to be very careful about what type of insecticide you use and how much of it you put on your plants.
Plan Your Defense Against Greenhouse Pests
Being aware of all the potential pests you might find in your greenhouse and following every preventative measure will save you time, money, and the headache of trying to beat back a full scale infestation. If your pest problem gets out of hand you may need to resort to throwing a full plant or two into the compost bin and no one ever wants to see that happen. There is a lot that can be done before you get to the drastic measures stage so just be aware of what you’re bringing in to your greenhouse, keep your greenhouse as sealed up as possible, and watch your plants closely to ensure so you can get rid of any insects before they’ve had a chance to really set up shop.