Indoor plants are extremely susceptible to pests, and they can be very difficult to get rid of. The comfortable temperatures indoors are attractive to many insects, and life indoors saves them from the natural predators that would kill them outside.
Once you have pests, it is easy for them to spread from plant to plant and threaten your entire garden, so it’s important to take steps to prevent infestations before they get started, and to catch them as early as possible.
Here’s how to get rid of indoor plant pests.
Choose Healthy Plants
It’s very common to pick up plant pests when you bring home a new plant. Before you buy a new plant, look it over carefully.
The leaves should be green, shiny, and lush, and stems should be smooth and even without cracks or scars.
Check the undersides of leaves and the potting soil for any signs of pests (more on that below).
Choose the Right Plants for Your Home
A plant’s best defense against pests or diseases of any kind is to be healthy and vigorous. A plant that is growing in the right conditions is less susceptible to pests, and better able to survive and recover an infestation.
Make sure that your indoor garden is full of plants that can do well in your lighting conditions, at your temperature and humidity levels, with your watering habits.
If you can, look up plant species and care information before you buy it, or ask someone at the gardening center.
Making sure you have the right environment not only helps to prevent pests, but helps your plants look their best.
Quarantine New Plants
Whether you are bringing home a new plant from the garden center, or as a gift or cutting from a friend, it’s always best to isolate new plants for a while in case they have pests.
Isolating new plants means keeping them well away from all your other indoor plants for the first month in your home.
If you don’t have the space to fully isolate new plants in a separate room, then keep them far away from your existing plants, without allowing the leaves to touch or the pots to sit right beside each other.
That way, if the new plant does have a pest problem, it won’t spread to the rest of your indoor garden.
Use Sterile Soil
Always use sterile potting soil for indoor plants. Potting soil may harbor pests and diseases, and the chances of that increase the more often the soil gets re-used. Earth brought in from the garden may also have diseases or pests.
You can purchase new, sterile soil for every plant and repotting, or use an oven or microwave to heat-sterilize your soil before reusing it on a new plant.
To sterilize your potting soil:
Place up to 2.2 pounds of soil in a covered but vented microwave-safe container, and microwave it for 90 seconds
Preheat an oven to 200°. Use a disposable aluminum roasting pan (or any oven-safe pan that won’t ever be re-used for food), and fill it with moistened soil. Cover the pan with aluminum foil and insert an oven-safe thermometer so that you can read the soil temperature without removing the aluminum foil.
Heat the soil until it is 180°, and bake it at 180° for 30 minutes. Do not allow the temperature to exceed 200°.
With either method, allow the soil to cool to room temperature before using it on a plant.
Take Good Care of Your Plants
Generally speaking, under-watering is better for pest prevention than over-watering. Standing water in plant containers or prolonged periods of soggy soil is a great environment for many plant insects, as well as for mold, mildew, and other problems.
Provide the right amount of water, and place your plants in a way that allows healthy air circulation around the leaves.
Feed Your Plants
Outdoor plants can access nutrients from the soil, where nutrients are constantly being added by rain, beneficial insects, and from decaying plant matter in the earth.
When outdoor plants need more nutrients, they can often simply expand their root system to find more.
But indoor plants can quickly deplete any nutrients in potting soil, and have no way to access more.
It’s important to use a plant food formula designed for indoor plants, and follow the instructions, so that your plants have all the nutrients they need to grow healthy roots, stems, and leaves.
Clean Your Plants Regularly
It may seem like cleaning your plants is an unnecessary chore, but regular cleaning helps to prevent pests and problems, and also helps your plants look their best. Dust on the leaves can block sunlight and prevent photosynthesis, even in a well-lit room.
Regular cleaning is also the best time to inspect your plants carefully for pests and diseases, so you can catch them early. If you can see or feel dust on your plant leaves, it’s time to clean them.
Here’s how to clean your plants:
- For small houseplants, fill a bowl or bucket with lukewarm water (never use warm or cold water, because both of them can damage the leaves of a plant). Hold the roots and soil inside the container (or use cling film to secure the plant inside the pot), turn it upside down, and gently swish the top of the plant around in the lukewarm water. Place it in a sink or bathtub to drip dry
- For medium sized houseplants, place them directly in a sink or shower and spray them gently with lukewarm water. Avoid using a high-pressure spray
- For large houseplants, you can use a cloth dampened with lukewarm water and wipe the leaves clean on both sides
- For very dirty plants that aren’t rinsing clean with plain water, you can dilute ¼ tablespoon of dish soap in a quart of water and use it to mist the leaves. Then rinse or wipe the plant as described above
- Using a dilute solution of neem oil as a leaf wash or cleaning spray can keep plant leaves healthy and naturally repel pests
Washing the plants is also a great time to also flush the soil, removing excess salts and nutrients that may be building up in your soil. Flushing the soil should be done once a month, and can easily be done while cleaning. Here’s how to flush the soil:
- Check the drainage holes on the bottom of your pot to make sure they are clear and water can drain freely
- Place the plant in a sink, bathtub, or outdoors where water can flow away freely
- Slowly pour water into the top of the pot, allowing it to flow out of the bottom. Pour it slowly enough that water doesn’t flow over the top, but instead flows downward through the potting soil. Pour four times the pot’s volume of water through the pot and potting soil to flush it thoroughly (so use a gallon of water to flush a one quart sized pot)
- Allow the plant to drain for 2-3 hours before moving it back to its normal location, and check the drip tray frequently for the next day or so to empty excess water
Prune Unhealthy Foliage
During the washing process, it’s a great time to also trim and prune unhealthy leaves. If leaves are dead, brown, or yellowing, the plant will look better and be more healthy if they are removed.
Gently tug on dead leaves and remove them if they fall off easily. If a leaf is yellow or brown, but resists being pulled away, use scissors to trim it.
You may also use scissors to trim away unhealthy parts of leaves without removing the entire leaf.
Control Pests Early
While washing, flushing, and pruning, look for signs of mold, mildew, insects, or other pests. Here are some of the key signs to look for.
Changes in Leaf Color
If leaves are yellowing, browning, spotting, or speckling, it’s a sign of potential pests. White, brown, or black areas are also a problem sign.
Changes in leaf shape or texture. If leaves are misshapen, wrinkled, curled, withered, or are sticky, bumpy, or fuzzy when they shouldn’t be, it’s a sign of problems.
Look for Signs of Insects
Even if you can’t see insects, you might see signs of webs or surface residue that indicates insects.
Isolate and Treat Troubled Plants
If you suspect a plant has problems, isolate it immediately.
Whether it has insects, a disease, or simple mold and mildew, the best thing to do is to move it far away from all your other plants while you diagnose and treat the problem, to prevent it from spreading to your other plants.
There are different products and treatments for all kinds of plant pests, and the best solution depends on what kind of pests you have. But the best way to get rid of pests on indoor plants is to keep your plants thriving and healthy all the time, to prevent problems before they start.