Everyone has problems with insects now and then in the garden, but pests on houseplants can also be a problem. That’s why Gardening Know How strives to provide answers to those in need. Here you will find the 10 most commonly asked questions we get when it comes to controlling pests indoors.

1. How to treat indoor plants for pests?

There are a number of bugs that commonly afflict houseplants such as thrips, spider mites, aphids and whiteflies. While these pests are all different, the methods of contending with them are, in most cases, quite similar. Generally speaking, you should isolate the affected plant from the rest of your houseplants, blast the insects off the stem/leaves with a gentle spray of water, treat your plant thoroughly with neem oil, closely observe and inspect your plant for further insect activity and then apply more applications of neem if deemed necessary. Neem oil is often the best go-to pest control, as it is considered to be a safe and effective insecticide for over 200 species of chewing or sucking insects.

2. How do I control thrips in the greenhouse?

Whenever you have a plant afflicted with an insect infestation, such as thrips, your first course of action should always be to isolate the affected plants from others so that the infestation doesn’t spread and become an even bigger problem. Heavily damaged leaves and flowers may be pruned. Try spraying your plant leaves and stems in a sink or shower and, working with your fingers, coax the thrips and their eggs off your plant. Repeat this cleansing again in a few days as a precautionary measure. If the thrips still persist after these cleansings, then repeated applications of either insecticidal soap or neem oil may prove fruitful in curtailing the infestation.

3. How to get rid of spider mites?

The best natural remedy for dealing with spider mites is to take a nozzled hose and spray your plant down to extricate the insects from your plant. The next best approach would be to administer an application of insecticidal oil, such as neem oil, or perhaps even a miticide. However, caution needs to be exercised with miticides given that they are a chemical based solution and, as such, the most toxic option presented here.

4. Not sure how to get rid of aphids. Can you help?

There are a few different ways to tackle this issue. Light infestations can be controlled by hand-picking, crushing the insects and scraping the egg larvae from the leaves. Another tactic would be to place the houseplant in the kitchen sink or shower and use the sprayer attachment to gently spray the aphids away.  As you are spraying, tilt the houseplant underneath the sprayer in such a way so you are not saturating the houseplant soil in the process. There are a number of sprays you can use to treat aphid infestations as well, including homemade garlic sprays, insecticidal soaps and neem oil sprays. You will probably need more than one spray application to fully eradicate the problem, so stay vigilant after every treatment to determine long term effectiveness.

5. How to remove pests from plants before bringing in for winter?

Before bringing your plants inside, a thorough inspection for insect pests is in order. Examine all the leaves and stems thoroughly, particularly the underside of leaves for small insects such as aphids, mealybugs and spider mites, just to name a few. While you could remove insects and their eggs by hand, a much easier and probably more effective means of dislodging insects would be to hose your plant down with a gentle spray. I would also go one step further and spray your plant with neem oil before bringing it inside as well, as an extra layer of assurance against bringing in any unwanted hitchhikers.

6. How to keep mice out of plants indoors?

The only way to remedy this issue is to eradicate the existing mice in your home and to prevent them from getting inside. Motivated house cats can be effective in helping you resolve this problem provided they can freely roam your house at night. Barring that, the use of rodenticides or snap traps (baited with bacon, peanut butter, etc.) may be utilized; however, snap traps are a more favorable and recommended option, as they are much safer to use around children and pets and prevent mice from dying and decomposing in out of reach places. In order to prevent mice from getting inside your home, you may consider enlisting the services of a professional pest control agent or you can try to address the issue on your own, which will require some sleuthing on your part. Look for any space that a mouse could squeeze through (and they can squeeze through incredibly small and tight spaces). Be on the lookout for cracks in foundations, gaps underneath doors and windows and in and around utility pipes entering your home. Mice like to bury food in and around houseplants, so be sure that house scraps are contained and that pet food is stored away after pets have eaten.

7. What is best way to get rid of scale on houseplants?

Regardless of which type of scale you are confronted with (soft, armored or mealybug), the method of control is pretty much the same. Isolate the houseplant in question. For light infestations, you may simply be able to just pick off or scrape any scale that are present and/or dab each scale with a cotton swab dipped in rubbing alcohol to kill them. A weekly application of neem oil, insecticidal soap or a homemade oil spray for at least a month is also recommended for controlling scale bugs.

8. What are the white worms in my houseplant soil?

If the worms in question are approximately ¼” long and look something akin to centipedes (flat and segmented) with long antennae, then they are most likely what are known as ‘garden symphylans‘ or ‘garden centipedes.’ These white, creamy, almost translucent looking critters attack root systems, destroying vulnerable seedlings and weakening mature plants. To combat garden centipedes in containers, try applying a soil insecticide to the potting soil. If this proves ineffective, your next measure should be repotting the plant in fresh potting soil after ensuring that the infested soil has been completely washed away from the roots.

9. How to get rid of gnats in houseplant soil?

The presence of gnats in houseplant soil typically suggests that your houseplant is being overwatered or is housed in a container without proper drainage. Proper watering is key to preventing gnats, as they thrive in damp soil. To discourage the developing gnat population, you could refrain from watering your houseplant long enough allow the top few inches of your potting soil to dry out. Adding chunks of raw potato to the top of the soil or inserting popsicle sticks with pieces of yellow sticky traps attached will serve to entice gnats to congregate in one place for easy disposal later. The most surefire means of eradicating gnats, however, is to completely repot the plant in fresh gnat free soil. When repotting, carefully extricate the plant from the soil and wash all the infected soil from the plant roots. If reusing the same container, be sure to wash it out completely in a weak solution of bleach water to kill any vestiges of gnat eggs or larvae that may remain.

10. Can a houseplant recover from whitefly damage?

Yes, a houseplant can recover from whitefly damage provided you have taken measures to ensure the whiteflies have been completely eradicated and are following good horticultural practices to prevent re-infestation. If you continue to follow your plant’s care plan, it is in the best possible position for a comeback! However, if you are still struggling with eliminating whiteflies, there are a number of things you can try. Force the whiteflies to disperse by hosing your plant down with water. Spray your plant with applications of insecticidal soap or neem oil, being sure to spray the underside of the leaves where they congregate. Reduce adult whitefly populations by sucking them up with a small handheld vacuum or by capturing them with yellow sticky traps. Trim the most heavily infested leaves and dispose of them outside. Inspect, and treat, your other houseplants for whiteflies as they have been known to transfer from one plant to the next.

We all have questions now and then, whether long-time gardeners or those just starting out. So if you have a gardening question, get a gardening answer. We’re always here to help.