Indoor Pest Control: Natural Remedies to Keep Common Houseplant Pests at Bay

Leaf by leaf, they slowly spread, seizing the vital nutrients found in foliage. These houseplant pests may be small, but they are pernicious.

But before you begin dousing a pest-ridden houseplant with chemical sprays, try these natural remedies to keep them at bay. In this day and age, even pesticides labeled as ‘natural’ does not always mean safe, as organic does not always correlate to non-toxic. Fortunately, with these natural remedies, most household pests are easy to get rid of.

Common types of indoor houseplant pests

Indoor pests are of a different breed than outdoor garden pests, though there are some overlaps – mealybugs, aphids, thrips, and slugs also thrive outside. Below are a few common indoor pests and several ways to thwart them. 

Spider mites

Spider mites are minuscule pests, more arachnid than insect, that often infest ornamental houseplants. They are difficult to see, and you’re more likely to recognize the damage: yellowed or stippled leaves and thin, filmy webbing. One way to get rid of spider mites is to combine a mixture of one cup rubbing alcohol and four cups water, then thoroughly apply the solution to the foliage. 

Spiders

A few gardeners are lackadaisical in their treatment of spiders, preferring to allow them to scamper in the dark crevices of their home. Others are more wary of this unwanted houseguest, preferring to acquaint it with the underside of their shoe. In most cases, spiders are harmless nuisances and seldom poisonous, but if they really bother you, essential oils can deter them.

Ants

Ants in the house can be a sign of other pests, as they are often drawn to aphids, scales, or mealybugs found in potted plants. They may be symptomatic of more insidious infestations, so be sure to carefully inspect each plant. Various ways to get rid of ants include spices such as cinnamon powder and diatomaceous earth (DE), which can be dispersed into the soil.

Scales insects and mealybugs

Scale insects and mealybugs are a parasitic class of insects that feed by drawing out liquids from a plant’s cells. As they can be hard to spot and get rid of, they are the bane of many gardeners. In general, brown scale insects have rotund, bark-like bodies that blend in with the surrounding foliage while mealybugs have a powdery white body. While it may be prudent to throw out the entire plant, there are instances where it can be salvaged. Outdoor gardeners will opt for biological controls – introducing their natural predators, particularly the lacewing; indoor gardeners will spot treatment using isopropyl alcohol.

Fungus gnats

Not necessarily a pest, fungus gnats are considered minor nuisances. Resembling fruit flies, they are attracted to moist and decomposing matter and are an indicator that a houseplant has been overwatered. Check your watering regimen or sprinkle some Bacillus thuringiensis (BT), and they should go away.

Natural ways to combat household pests

Be cautious of growing conditions  

The fortuitous gardener needs never worry about indoor pests. For some, no matter how many houseplants they amass, they rarely encounter a single pest. For others, infestations are much more frequent, and may be a sign of subpar conditions. Healthy houseplants are less prone to becoming overrun by pests, and infested plants are often a sign of neglect or unfavorable environmental conditions. Sometimes, less frequent watering will deter pests like fungus gnats, which thrive in moist environments. Vego Garden's innovative rolling planter, which can be wheeled indoors once the cold weather hits, allows you to moderate your watering, leading to healthier plants. 

Use DIY sprays         

Sometimes, tossing away a severely infested plant is the best way to save the rest. If it’s not too late, an afflicted houseplant can be saved through quarantining and an application of DIY sprays – a multi-pronged approach may be necessary. Insecticidal soap or neem oil can be utilized to combat infestations. 

Make your own organic remedy by mixing three teaspoons of neem oil and one teaspoon of unscented castile soap with water, then spray the mixture directly on plant leaves. Insecticidal soap is similarly made, with a concoction of ¼ cup vegetable oil, one tablespoon dish soap, and water in a spray bottle. As it goes without saying, the liquid dish soap should be free of fragrances, bleach, synthetic dyes, and other chemical contaminants. 

Use essential oils       

The first line of defense is to seal off entryways where pests can infiltrate. For an additional layer of protection, keep pests at bay with sprays derived from essential oils. Essential oils made of tea tree, lavender, eucalyptus, and peppermint are recommended – add one tablespoon of any of these to one cup of water and spray around the house. Tea tree oil has been shown to deter spiders and remove aphid infestations, with a mortality rate of 80 percent. 

Use orange peels, spices, or coffee grounds    

One of the easiest ways to repel pests involves ordinary household ingredients. Orange peels, either as a spray or diced up and placed directly in the soil, can be an effective way to ward off pests. Since orange peels and other citrus fruits are high in nitrogen, they can also be used as natural fertilizers to help enrich the soil structure. Cinnamon powder and coffee grounds have been used, to varying degrees of efficacy, and are recommended for less severe pest problems. 

Use diatomaceous earth

Food-grade diatomaceous earth, which is less expensive and less hazardous than pool-grade, is often used to treat insects with hard exoskeletons, such as ants, cockroaches, and beetles. They will work by either removing the pest’s food source, in the case of fungus gnats, or kill directly by damaging their exoskeletons. 

Use biological controls 

Lastly, if all else fails, biological controls may be necessary. Houseplant enthusiasts have reported success with Bacillus thuringiensis (BT) and beneficial nematodes. BT is a bacteria that yields a toxin that will block an insect’s digestive processes; different strains are effective against different pests. Nematodes are microscopic worms that feed on a variety of pests, including root aphids, whiteflies, and gnats.