The 3 Ways How Aphids Get Indoor (and How To Avoid It)

Despite aphids being common in outdoor plants, how can you suddenly have an aphid infestation indoors? Here is what based on our years of experience are the most common sources of aphids in indoor plants.

Aphids are brought indoors in three ways 1) through open windows as they can easily be carried out by the wind 2) hidden in the fur of domestic pets like cats and dogs or 3) hidden in the soil of plants brought indoors.

Aphids, although a pest for your indoor plant, are pretty fascinating insects that developed countless adaptations to be able to spread and multiply effortlessly even indoors. Knowing their superpower will allow you to spot them earlier, fight them and prevent future indoor invasions.

Aphids Infestation Indoor: Five Cool Tricks They Do

I totally agree that aphids are a pest that can seriously affect the well-being of your plant. But, at the same time, when you start knowing a bit more of them you (or at least me) cannot stay indifferent by their natural ability, that at human scale would be massive superpowers!

Knowing them will also give you more instruments on what to do to both prevent and combat them when you find them on your indoor herb.

Trick 1 – Hiding

Aphids, grow up to 7 millimetres depending on the species although many of them are way smaller (1-2 mm). This makes them hard to spot if they do not land straight in your face. 

This might be the reason why you have aphids indoor. Indeed, they can find thousands of different ways to land on you or cloths during your afternoon run, while picking up the kids from school or use your dog as a free ride to your home. Countless are the occasions in a normal daily routine in which close to a green area/plants one (or more) aphids can land on you. Moreover, many of them evolved not only to be not only green but also brown, red, grey and white. So, even if you do not were green clothes might be hard to spot.

What can you do? Now that you know that your clothes might be an easy ride for aphids you can get rid of your outdoor clothes before entering the room where the plant is located making for the difficult to reach it. If your dog spent hours in the grass or outdoor with high vegetation it will be very likely to have a few aphids hidden in its fur. A shower is suggested.

Trick 2 – Wings

This is by far the capability that fascinates me the most. Imagine being able to give birth to offspring with wings whenever you want? This is what aphids do. In case of food shortage or at specific seasons some aphids species have developed amazing adaptation mechanism that allow them to activate the part of their DNA responsible to produce perfectly functioning wings in their offspring. 

Aphids indoor look
Example of aphid born with wings – Photo by Mick E. Talbot from Flickr

This might be the reason why you have aphids indoor. A window left open on a hot summer day with your plant probably in front of it to leverage lots of sunlight is a call to action for hungry aphids that can be able to fly from a nearby plant to your potted herbs. 

What can you do? If equipping your windows with mosquito nets (that also bring advantages to you by stopping other annoying insects in the warm summer evenings), another alternative is to cover your plant with a net when your windows are opened.

An open window can be enough to give aphids access to your plant – Photo by Phil Roeder from Flickr

Trick 3 – Aphids Hibernation

Yes, you read well. Aphids can hibernate during winter in two ways, again depending on the species (and there are 4000+ with probably more to be discovered):

  • Under eggs form: they can hibernate during the cold winter without any issues;
  • Under active form as adult or nymph (baby aphids)

In both cases, this is possible due to the presence of powerful substances like glycerol and mannitol in their body that help them tolerate low temperatures without internal damage. 

This might be the reason why you have aphids indoors. Indeed, let’s assume that you bought a cheap and small basil plant in a supermarket with the objective to revive it and make it a big basil producer for your pesto. What’s happened if a few eggs were already under a leaf in hibernation? You probably would never know until you do not see them having a walk on your plant leaves.

What can you do? This is more preventive action: I would visually check the plant. The “good” news is that if you have an egg, it is very likely that there are many more. Indeed aphids are very prolific making your task to find eggs easier as often they are in high number close to each other.

An egg looks like a spherical or egg/bean-shaped (around) 1mm long cocoon under a leaf or on the soil (brown, yellow, black, or white in color). If you see them then just do not buy the plant. 

Trick 4 – Aphids clones (female only)

Yes, this is crazy! Humans are hardly struggling to understand cloning and those annoying 3 mm insects are doing this probably for hundreds of thousands of years if not more. A female aphid, if it is of the right species, can clone itself giving birth to multiple copies of herself, that, in turn, can do the same.

You can easily understand that this process can go on and on if food is around (your precious plant leaves) making them unstoppable. Given their dimension, they do not need massive amounts of food as so one single leaf can be enough for hundreds of them!

This might be the reason why you have aphids indoor. Indeed, males are not necessary to start a colony that “appears from nowhere”.

What can you do? In this case, being able to spot one single aphid might be extremely challenging. However, most of the time is more than one aphid that colonises your plant.

Trick 5- Aphids can generate an army in no time

As said before one aphid (remember, a few millimetre insects) can reproduce itself alone. And this can happen at a tremendous rate. Aphids can produce up to 150 offspring in just a month. Let’s put this in perspective.

Suppose you have 1 female, each one producing 150 offspring a month. After 2 months you will have 20+ thousand aphids. Put them in a line and you will have a 40 meters queue of aphids, the equivalent of a 10-floor building! 

That’s crazy and probably the question to your main question “Where all these do come from!”

How do I get rid of aphids in an indoor plant?

This is really a hot topic with countless techniques available, from natural products to chemicals or even using other insects. This will be the object of an in-depth article. The good news is that many of these techniques are effective, although you should be careful to not damage the plant in the process and use, whenever possible, natural remedies. 

Among the most common and easy to apply right now with what you have at home you have:

Aphid removal strategy 1 – Manual and water

In case you have been careful in monitoring your little green friend and you have spotted a starting aphid colony, I would go for a manual removal with a jet of water on the leaves or/hand using your hands with some tissue. The only things to be careful is to perform this operation on a daily basis until you do not find aphids anymore. Check also for eggs. Remove whole leaves if they are heavily invaded.

In case of an aphid infestation at an early stage, manual removal with water might be enough – Photo by eelke dekker from Flickr

I would recommend performing such operation on a daily basis for 1-2 weeks, or until, for 2 weeks in a row, there are no aphids around.

To take care: do not accidentally overwater your herb with the water you used to remove the aphids. I would recommend placing a plastic bag (the ones from the supermarket) to cover the plant soil and collect as much water as possible. This will also prevent aphids from dropping on the soil. 

Aphids removal strategy 2 – Mix of vinegar and water

This is a pretty “do it yourself” known approach to fight aphids in case of a more serious attack. Mix 1 glass of vinegar with 2 glasses of water and place the solution in a spray with which you will water aphids and eggs. This solution will very likely kill them instantly.

To take care: vinegar is an acidic substance, and although diluted, I would recommend using the solution as little as possible (and do not increase the ratio of vinegar in the hope to create a more potent solution). Indeed, the acetic acid is ending up in the plant and in the soil, where the roots might suffer. In such small quantity (only a third of the solution is vinegar, and only 5% of it is acetic acid) should not be a problem, but be cautious.

As a suggestion, I will start manually removing all aphids as much as I can (process #1)  and then use vinegar to be sure to have eradicated even those that I have missed. 

Aphid removal strategy 3 – Dish Soap

If for any reason you do not have vinegar at home, you can always opt for dish soap. In this case, as it is a chemical, a very mild solution should be used (one teaspoon of soap for each litre of water) and again spray your leaves. This should be applied every two days for 2-3 weeks.

Dish soap is an excellent remedy to get rid off aphids – Photo by gagilas from Flickr

To take care: the same recommendations we discussed with vinegar here applies. Hence, do not exaggerate, do not change the ratio of dish soap to water, and try at first to manual removal the aphids.

Three way aphids get indoor infographics
Sneaky Ways Aphids Get Indoor – Infographic

Can You Have Missed “Hidden” Aphids?

If you focus your attention in removing them from the leaves, well done! Indeed, most of the aphids live beneath the leaves and on the plant stems. However, there are also a handful of species that thrive in the soil and feed on your plant roots.

Of course, I do retain you to be very unlike to have a plant invaded by different species of aphids that thrive both under and above the soil. This is quite uncommon. However, if you notice your plant, without any apparent reason, to become limp and day perhaps the culprit might be underground.

How to find them? Well, an easy way is to dig your finger in the soil and with the help of a bit of light (your cellphone should be enough) look for any little pear-shaped white/brown blob moving around.

If your plant starts suffering the first symptoms very likely you have already a decent colony and so it should be easy to detect. 

In such a case, although quite a serious situation. One of the most common remedies that I can suggest is the use of biological help from nematodes. These are tiny animals (way smaller than aphids) that inject harmful bacteria in the body of the aphid that will inevitably die. All this process leave untouched plants and other insects so it is totally safe.

In practice, you can buy them in a small plastic package in suspension with water. It is recommended to add further water (following the label instruction) and then, at dawn (as light-sensitive) add them in the infested soil.

In Which Seasons Are Aphids a Problem?

Aphids are insects, and, as the majority of them, do not have any system to keep them warm. Hence, they can thrive only in the warm spring and summer weather. However, in winter they do not disappear. The egg produces close to the winter season hibernate ready to hack and invade your plant during early spring. 

So, in theory, winter is the best time for you to breathe? No! Indeed, your plant is indoors where there is no winter! Hence, in such a case, eggs do not need to enter in hibernation as the ambient temperature is already right and you need to be on guard for aphids all year round.

How long does an aphid live? Aphids can live up to around a month and a half but they get fully mature typically in less than a week.

Are there natural aphid natural predator? Yes, a few types of wasps, earwigs, lacewing larvae and ladybirds are the most notorious aphid’s predators. Some of them are currently used by gardeners as a biological arm against aphids.

Do aphids bite humans? They can bite humans but this is quite rare and only a handful of the largest aphid species is able of that.

Further Readings

21 Tips to grow massive basil

Should you eat leaves with holes (aphid and other cause)?

Best container size for your basil

Best potting soil for your herbs

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