Although they are pretty much considered to be an inevitability within even a small collection of houseplants, there is never a good time to deal with pest infestations in your home. Common houseplant pests can be persistent, prevalent, and hard to eradicate, which is why proactively implementing some prevention strategies in your home can make a huge difference.
There are several preventative measures you can take to reduce the incidences of pest infestations in your home. Implementing proper plant care, careful inspection and monitoring, and maintaining the proper environment for your plants will help minimize the opportunities common pests will have to successfully infest a houseplant.
As you read through the following tips, recognize how almost all of them are essentially best care practices that keep your houseplants stress-free, well-maintained, and in good health. This is because a strong plant is much less likely to succumb to a pest infestation.
In this article, we’ll go through several care and maintenance tasks that can be easily added to your current plant care routine, which should contribute to your plants’ overall wellness and bolster their resistance to pests through environmental conditions and natural defenses.
Understanding What Your Plant Needs
Before we dive into pest prevention, it is important that you have an understanding of which plants you have in your home and what their specific needs are. While the following tips are, overall, good general advice on how plant care, maintenance, monitoring, and environmental factors can impact pest infestations, how you apply that knowledge may differ depending on the types of plants you keep.
For example, knowing that spider mites prefer drier climates might prompt you to increase humidity levels for certain plants, but what if those plants struggle in damper conditions? Rather than jacking up the humidity level too high, you may need to experiment with more conservative levels so you can find the sweet spot that inhibits spider mites but doesn’t cause the plants any unnecessary stress.
Having a good understanding of what factors make your houseplants happy and healthy will provide insight into how you should apply these preventative measures to each individual plant in your collection.
Tips for Pest Prevention in Houseplants
As you may have guessed by this point, the best prevention of common plant pests comes down to how healthy the houseplant in question is. Plants have evolved several of their own physical and chemical defenses to resist infestations, but these defenses are only sustainable when the plant is in good health.
To maintain these natural defenses, we must be able to provide our houseplants with the proper care and environment that allows them to grow and thrive. All of the tips mentioned below are simple things we can incorporate into our daily, weekly, and monthly care routines to prioritize our plants’ health and minimize environments that are attractive to fledgling pest populations.
Proper Watering
Arguably, the most important aspect of proper plant care is watering your houseplants the right amount, at the right frequency, and being able to recognize when you get it wrong.
Every plant is a little different, but in general, avoiding overwatering is one of the biggest keys to maintaining a healthy plant, and therefore, a strong pest prevention method.
Overwatered plants tend to struggle with water and nutrient absorption, gas exchange, and nutrient transport, all of which can lead to serious health issues that cause drooping, wilting, leaf drop, chlorosis, and rot.
Overly wet conditions can also foster the growth of harmful diseases and fungi that weaken a plant’s overall health. All of this can cause the plant to prioritize survival over things like pest prevention. Also, these same conditions can be the perfect breeding ground for pests like fungus gnats.
Underwatering can be just as detrimental to a plant’s natural pest defenses. Overly dry conditions weaken the plant in a variety of ways, causing wilt and leaf burn. These create opportunities for pests like thrips or spider mites to gain a foothold on a compromised plant.
To avoid both watering extremes, pay attention to when the top inch or two of soil has dried out. Don’t worry…the soil is still plenty damp near the bottom of the pot. At this stage, water your plant deeply and thoroughly, and allow any excess liquid to drain from the bottom of the pot (yes, you should have drainage holes in your pot).
This method is a great indicator of the proper time to water without having to stick to an arbitrary weekly schedule. It also keeps things from ever becoming too damp, which is when you start to see fungus gnats arriving.
Give Your Plants the Right Light
Another big plant care factor that can go a long way in fostering a plant’s natural defenses against pests is proper lighting.
Although many plants can tolerate a wide range of sunlight exposure, we often underestimate the impact too much or too little light has on a plant.
For many plants, too much sunlight (or, in many cases, direct sunlight) will burn their leaves and tender growth. This results in the plant allocating a tremendous amount of energy and resources to trying to repair the damage, often at the detriment of its overall health and defense mechanisms.
Alternatively, too little light creates an environment where the plant is constantly trying to secure more sun exposure, which often results in leggy growth. Production of this weak, scraggly growth consumes a lot of the plant’s resources and can be an easy target for sap-sucking insects that are in search of soft plant tissue to pierce their mouthparts into.
It is important to understand not just what your plant can tolerate in terms of light exposure but what it actually prefers. By providing it with the sunlight it actually needs to thrive, you aren’t limiting things like photosynthesis, nutrient production and storage, or nutrient allocation, which can all become bottlenecks to maintaining good health and strong growth.
Temperature and Humidity
Certain environmental factors can have a huge impact on how well a houseplant performs in our home. Some we don’t have much control over, but temperature and humidity are two we can address.
In general, most of us keep our homes relatively warm and dry, at least from the perspective of houseplants. We commonly have a narrow range of temperatures that we find comfortable, and the methods we use to heat our homes tend to dry them out, as well.
For the most part, this is all well and good. Many houseplants prefer a temperature range between 65-80° F and can tolerate lower humidity levels that we find comfortable. However, certain houseplant pests also prefer these same ranges, which makes them more of a threat.
Thrips and spider mites thrive in warm, dry climates, which is why houseplants can be appealing hosts. Our indoor temperatures are warm enough that they can actually speed up these pests’ lifecycles, allowing them to build up populations faster than if they were outdoors.
Some of us who have plants that prefer more humid environments have tried to increase moisture content by adding humidifiers to rooms in our homes. This is often a good move from a plant care standpoint, but it can also be too much of a good thing.
Overly humid environments can cause consistently damp conditions that many sap-sucking insects prefer. Aphids, scale, mealybugs, and whiteflies might be attracted to very humid microclimates, and fungus gnats will most definitely find their way into waterlogged soil.
Depending on the types of plants you keep in your home, you might be able to find a sweet spot in regards to temperature and humidity that keeps the plant healthy but doesn’t promote the recruitment of pests.
Avoid temperature extremes by keeping your home between 65-75° F, whenever possible. Humidifiers are great for plant health in most cases but try to find one that has a built-in sensor so it will shut off when the room is between 45-60% humidity. This will still provide benefits for the plants but should discourage dry climate bugs without producing too much moisture that might attract other pests.
Fertilizer
Feeding your plants is another care task that should happen regularly. Supplemental feedings of nutrient-rich fertilizers will ensure your plant has everything it needs to stay strong, healthy, and promote sturdy growth, all of which help it resist pests.
There is some research out there that states overfertilizing certain plants can actually attract pests, but in my experience, the risk of overfeeding your plant is minimal compared to the benefits the additional nutrients have on plant strength and health. As long as you’re thoughtful about how you apply feed, you shouldn’t have to worry about overfertilizing.
In general, using a well-balanced liquid fertilizer about once a month is a good starting place for most plant varieties. There are, of course, exceptions to this guideline, so be sure you research your specific plant varieties before applying any feed.
To be extra conservative, dilute any fertilizer to half strength just to make sure you avoid nutrient burn or any other negative side effects of overfeeding. Afterward, observe the plant for any signs of distress or, hopefully, improved performance to help determine when to feed next. You may find fast-growing or vigorous plants can handle fertilizing every three to four weeks, while other houseplants only need feeding every six to eight weeks.
Clean Your Houseplants
Another simple task you can add to your care routine is occasional plant cleanings. This might not seem necessary, but a simple session of wiping down the leaves of your plant can make a big difference in its health and your ability to detect potential pest issues.
First and foremost, when you wipe down leaves, you are getting up close and personal with the plant, perhaps focusing your attention on the plant’s structures more than you usually would. If you see any signs of distress, damage, or any little insects, you can take appropriate steps before things get out of hand.
Also, leaves free of dust and debris function much better, with better rates of photosynthesis and more efficient gas exchange through leave stomata, both of which improve the overall health of the plant.
Each time you clean, you might also be removing any lone pests trying to start a population on the plant. Simply wiping down leaves with a damp cloth can physically remove adult pests, larvae, and eggs from plant structures, keeping a potential infestation from ever getting started.
Spacing
Something as simple as where you decide to place your houseplant can have a huge impact on its tendency to harbor pests. Plants that are placed in the wrong environment or crammed together in one area can experience dips in their health due to poor conditions.
Oftentimes, plants get grouped together in a space based on how they look together without much thought put into whether or not they have enough space or the right conditions to thrive. Crowded plants also experience microclimates of variable humidity, poor air circulation, and, if pests are present, a higher likelihood that they will become infested.
All of this can be remedied simply by giving each plant a little more room. By providing a bit of physical space between plants, unhealthy microclimates are eliminated, and the chances of cross-infestations by pests are greatly reduced.
While you are considering how to properly place your houseplants, you should also be mindful of the environment around the room. Common areas for pests to enter the home are through open doors and windows, but you should also look for any cracks or crevices around window frames where critters might decide to crawl through.
Pruning
Another maintenance task that has a huge impact on pest prevalence but only needs to be done occasionally is pruning.
Over time, as plants put out new growth, sometimes the oldest growth can begin to wither and die. This shedding of older, less efficient tissues in favor of new, robust growth is often a normal part of a plant’s process, so it isn’t something to worry about in and of itself.
However, wilting, dying, or otherwise weakened growth can be a target for some pests. As the plant prioritizes new growth, many of the natural defenses no longer apply to the old growth, making them a perfect landing pad for a potential infestation.
While many folks opt to let the plant drop old leaves and stems at its own rate, if you suspect or fear a pest infestation, you should consider pruning back these older plant structures occasionally.
Additionally, many vigorous houseplants actually benefit greatly from occasional maintenance prunes. Sometimes, plants can grow to become pretty crowded and thick. This dense foliage might be seen as a safe haven for plant pests to feed and reproduce in. Crowded growth can also hold excess moisture and have poor air circulation, which can harbor diseases and rot, which would have a detrimental effect on a plant’s health.
If you have any houseplants that have grown overly large or especially dense, you might consider thinning them out a bit with a few strategic prunes. Even just by removing a few branches, you are opening the plant up for better air circulation and light exposure, while eliminating potential problem areas where pest detection and treatment might be extremely difficult to carry out.
Monitoring
Unfortunately, even if you are nailing all these preventative plant care tasks, that still doesn’t mean you can completely eliminate the threat of a pest infestation. Sometimes, these annoying bugs still find their way onto our houseplants.
Because of this, implementing a few monitoring methods into your plant care routine is yet one more preventative step you can take to protect your plants.
Monitoring basically refers to watching your houseplants carefully for signs of pests so you can catch an infestation as early as possible, making any treatments you choose to deploy all that more effective.
One good way to start this is by regularly inspecting your plants. Really get up close and personal with them, looking at all the plant’s structures, especially the undersides of the leaves. Look for any of the most common plant pests or for signs of feeding damage.
A good time to do this is during a watering session or whenever you are cleaning your plants.
Another good tactic that will give you the jump on any flying insects like fungus gnats, whiteflies, thrips, and aphids is to install sticky cards within or near your plants. These cards attract adult flying insects that get stuck to the surface and eventually die. Sticky cards are easy to change out and can alert you to certain pest infestations before they really start to take off.
Another really important time to inspect for pests is any time you bring home a new houseplant to add to your collection. Pests are often introduced to the home through the plants we bring inside, so by taking the time to really look through any new additions can save you a big headache later on.
Ideally, you can keep any new plants isolated from the rest of your collection for at least a few days, if not a week or two, just to be extra sure there aren’t any unwanted stowaways hiding in its foliage.
Preventative Products
Lastly, if you are so inclined, there are several different preventative products you can use on a regular basis that either actively discourage or at least make it more difficult for pests to infest a houseplant.
Personally, I avoid any chemical-based preventatives mainly because I don’t want to deal with the hassle of applying them correctly and according to their labels. I also don’t want to reduce the efficacy of certain products, opting to save them for when I really need them to work against an infestation.
Instead, you can try natural products that many pests find unappealing.
Diatomaceous earth is a powder made from the desiccated exoskeletons of microscopic ocean organisms. Although soft to our touch, DE is actually very jagged and sharp to soft-bodied insects and pests. It can be applied to the surface of potting soil to discourage adult fungus gnats from laying eggs or emerging from the soil. It can also be sprinkled on plant structures, where it will destroy any adults, nymphs, or eggs that come into contact with it.
Alternatively, many people spray diluted peppermint oil in and around their houseplants. Many pests find the smell very unappealing and will actively avoid it. It’s easy to use and doesn’t need to be reapplied all that often, making it a great, passive pest deterrent.
Final Thoughts
When it comes to houseplant pests, an ounce of prevention is worth a pound of cure. Rather than always reacting to pest infestations, we can bolster a plant’s natural ability to resist these bugs through deliberate and proper plant care so pest issues happen less frequently and with less severity. By creating an environment where your houseplants thrive, you can keep them strong, healthy, and pest-free for years to come.