How To Identify, Control, & Prevent Spider Mite Damage On Houseplants

You look at your houseplant and something does not add up… It is covered with tiny little what looks like dandruff, but they are insect-like creepy crawlies in a thin web… What is it? Spider mites! How did your houseplant get to be infested? What are spider mites? Are they dangerous for your plant? But, above all, how can you get rid of spider mites on plants?

Spider mites pose a serious threat to the health and even life of your houseplants. They are also difficult to spot when they start the infestation. There are three main ways of treating plants with spider mites, and the most practical and effective one in most cases is to treat the plant with natural insecticide. This, however, is a long and laborious process.

If spider mites are a problem with your houseplant, they won’t be any longer after you read this article.

In fact, we are going to see who they are, why they spread so fast but also, and more importantly, how to get rid of them!

3 Ways to Get Rid of Spider Mites

Spider mites are not easy to get rid of. Be prepared for a bit of trouble and strife… There are three main ways of treating houseplants hit by spider mite infestation:

Neem oil, this can work for less advanced cases of spider more infestations. It is easy but it has limitations.
Treating your plant with a natural insecticide; this works well but it takes lots of time and care.
Changing the atmospheric conditions your plants live in; this is the high tech solution. It is easier to use, because you won’t need to clean each leaf in turn, but it requires the right setting and equipment.

What Are Spider Mites?

Spider Mites hide under the leaves of your houseplants; they are tiny, almost invisible to the naked eye, but spider mites have one thing in common when you see them…

A spider mite never comes alone. In a matter of days, you will have like a small city of little spiders on the leaves and stems of your plants, all crawling around and all weaving a tiny web…

They are not actually insects, but arachnids of the family Tetranychidae, so, the name is quite apt, as they are closely related to spiders.

They have eight legs when they are adults, in fact, like spiders. But unlike spiders, they don’t prey on insects. No… They suck the sap of plants. Basically, they are the vegan and undersized version of spiders.

Why do they weave a web then, you may wonder? Spider mites wave webs to protect themselves from predators.

They can be of many colors, many are red, some are yellow, beige, brown etc… You got the picture. However, they all have one thing in common: their size is diminutive. They are never bigger than 1 millimeter.

Small but quite active in the bed department, each female spider mite lays about 20 eggs a day, and this explains why they appear suddenly.

Are Spider Mites Dangerous for Your Houseplant?

Spider mites are not good, for sure. Because they feed on the sap of your houseplant, they will certainly weaken it. In some cases, especially if the plant is young, tender or is weak, they may even end up killing it.

So, spider mites are a serious threat to some plants, and they are very unattractive on all plants. This is why if you see them, you need to act very quickly.

What Damage Can Spider Mites Cause to Houseplants?

A few spider mites will cause little damage to your plant. The problem is that they multiply fast and soon they will establish a colony of tiny mites…

To suck on the sap of your plant, they will pierce through the epidermis, the skin of the leaf, and they will usually do it where it is weaker, on the bottom part of the leaf. This also makes it more difficult to spot them though.

If you don’t discover them in time, they will cause visible damage to the plant: first you will see tiny spots on the leaves. A pattern called stippling will appear; it looks like the leaf has a pattern of solid points and less solid points in small patches.

Then, the leaves of your houseplant will change color, turn pale and even yellow, and finally they will curl and fall off the plant. This is because the spider mites have sucked so much sap that the leaf has no more energy.

In the long run, this can cause the death of your houseplant.

The University of California reports the different type of damage you can find on different plants due to spider mites:

On annual plants, spider mites can also cause sunburn and edge burn, as they reduce the leaf surface the plant has.
On plants with pods, spider mites will attack the pods themselves, damaging and destroying them.
On ornamental plants in general, they have of course a negative effect of the look and beauty of the plant, but they can also lead to plant death.

Spider mites are particularly dangerous in greenhouses, where they multiply fast and find the perfect conditions to grow their colonies.

Why Do Houseplants Get Spider Mites?

There are many factors that can cause a spider mite infestation on your houseplant. You hardly ever see them outdoors, but indoors, they are far more common, why?

To start with, you may just not notice them outdoors; but there is actually a factual difference: spider mites live in colonies in dry and hot places, and they proliferate where they have no predators.

Homes tend to be dry and hot, and spider mites like temperatures around 80^oF (27^oC). What is more, they are already sheltered from predators as almost invisible guests on your living room.

They tend to follow when insecticides are used; this is because these products kill their natural predators. This already explains why using insecticides is not a long term solution, but actually a major cause of spider mite infestations.

Conditions that lead to spider mites On Plants

It’s not easy to spot spider mites early on during the infestation. They are very small and they hide on the bottom of the leaf. But the earlier you catch them the better it is.

To start with, keep in mind factors that favor the spread of spider mites:

High temperatures of 80^oF (27^oC) or above.
Dry air and atmosphere. Unlike other pests and ailments, spider mites do not like humidity.
Indoor spaces and greenhouses are more susceptible to infestations.
Places where the ecosystem is damaged, like areas where insecticides are widespread in the countryside or urban spaces, are breeding grounds for spider mites.
Plants that touch each other. Mites tend to stay close to each other; if there is contact among pants they will easily crawl form one to another.

Getting rid of spider mites: symptoms and diagnosis

Keeping these in mind, you should always keep inspecting the leaves of your plants for symptoms of a spider mite infestation:

The telltale sign is when you notice patches on the leaf where the texture is not intact. They will become less thick, look lighter and at times even turn translucent. They look like patches where the leaf has thinned.
Other signs may be the curling and dying of leaves.
Leaves will often turn dry, with symptoms similar to sun burn and edge burn, before they die.
You may notice a white dust around the plants. This is due to parts of the web falling off the plant.

If you notice any of these signs, then check the bottom of the leaves. You may even want a magnifier to do this; some are so tiny that they are barely visible to the naked eye.

Check at the base of the leaf in particular; why? They tend to hide there, just where the leaf is attached to the petiole (the little stem). This is where they start and where you will find the highest concentration.
If the leaves have grooves, check inside the grooves. You k ow by now that these are tiny pests that like to hide, and groves make perfect homes for them.
Don’t expect moving beings; they spend lots of their time stuck to the leaf and covered by a protective web, so, they will appear like dandruff, dust, or small grains, rather than insects like ants, who never stand still.

If you see any of these, please don’t waste any time. Act fast and thoroughly.

Once you have found that a plant is infested, do check all the ones around it.

Getting rid of spider mites: the solution that does not work… showering!

“My friend told me that for spider mites I need to shower my plant vigorously,” I hear often hear. Well, don’t’. It is not a solution.

It is useless and it risks damaging your plant. In fact, the spider mite web is hydrophobic; it literally repels water, and they will stay inside their little nests dry and safe while you use a strong water jet of water that can break the leaves, stems and damage your plant.

So, if you stumble across articles and videos that suggest this remedy, ignore them.

Get Rid Of Spider Mites On Plants With Neem Oil

Neem oil is a remedy, but it works better if the infestation of spider mites is small and new.

If you notice just a few of these tiny creatures at the base of the stem, then you may use neem oil.

Using neem oil for spider mites on houseplants has some advantages:

It is simple.
It is cheap.
It is fully natural.
It will not affect your plant at all.

You will need a rough make up brush or a paint brush (not rough), neem oil and a cheap spray bottle:

Pour the neem oil into the spray bottle.
Spray the plant; make sure you cover the top and bottom of the leaves and all the stems. This, for many people is enough, but, to be safe…
Brush the plant gently and in the direction of the veins and grooves of the plant. Don’t forget the stems and bottom of the leaves.

Neem oil can completely stop the infestation of spider mites when the colonies are small, but it is known to reduce the colony even in serious cases. So, this can even be a first step in case you are not ready for the more laborious solution.

What is more neem oil works as prevention from spider mites infestations. This is a key point, because the treatment is long, detailed and laborious.

So, if your plants are at risk of spider mites, a simple spraying of neem oil will save you lots of work in the future.

Getting rid of spider mites: the full treatment

If the spider mite infestation is serious, for example if the leaves have sizable damage or if the mite colony is big, then you will have to use the full treatment. It is not expensive, but it takes time and a lot of attention.

You will need a brush (a rough make up brush or a paint brush, one that is hard enough to scrape the webs but does not damage the leaf), a spray bottle, alcohol, water, Castile soap, eucalyptus essential oil and a pair of sterile and sharp scissors.

You may also want to use an old towel or cloth, as you will end up brushing the plant in your lap; I know it from experience… You may even want to wear gloves, like surgical gloves! And maybe a mask because of the alcohol fumes; they are not noxious but they can make you heady.

Preparing The Spider Mite Insecticide

Spider mites are small but multiply very fast. They are almost invisible but they can wreck havoc on your plants. Now you know what favors them, how to recognize them and that there are ways of getting rid of them. One is simple but only works for small colonies. The second is laborious, but for many it is the only effective solution available. The third is less labor consuming, but you need special equipment and a special environment to use it. So, we are left with the prospect of spending long hours cleaning all our plants unless… Unless you prevent them from coming; neem oil sprayed every now and then will do the trick. Alternatively, a few drops of eucalyptus, lime, rosemary, cinnamon or peppermint essential oil in a spray bottle to vaporize on your plant every fortnight or weekly in the hot season will keep spider mites at a distance from your houseplants. This way, instead of having to say goodbye to spider mites after a long struggle, you won’t even have to say hello to them.

We will take a one liter spray bottle as measure; do adjust according to your needs.

Grate 50 grams of Castile soap into a bowl.
Melt the soap on bain-marie.
Pour the soap into the spray bottle.
Add about 66 cl (22 oz) of lukewarm water. This should be about 2/3 of the bottle.
Add the alcohol to fill the bottle.
Add a few drops of eucalyptus essential oil.
Seal the bottle and shake well.

If you want a fully natural insecticide, the alternative is easy but pricey. You will need to mix one tablespoon of Rosemary essential oil for each ounce of water. For a liter, that’s about 33 spoons… But if you have no money problems, or just a small plant, it may be worth it.

Preparing your plant for the treatment

Now you have the insecticide, we need to prepare your houseplant before you use it on the spider mites. Yes, this is a homemade and natural insecticide; the mites will die as soon as the alcohol touches them. It is, if you are concerned, a quick death.

Still even before you do this, there is something you may need to do: if there are any seriously damaged leaves of stems, cut them. This has some advantages:

Your plant is weak, and it will not be able to save the damaged leaves.
You will reduce the foliage and stems you will need to treat, making the treatment simpler and shorter.
You will have better access to the leaves and stems you need to treat.

How you will go about it depends on the foliage and shape of the plant. For example, with a plant like a Philodendron, which has large leaves, you will do it leaf by leaf. With roses, you will need to treat groups of leaves together, and spider mites quite like the world’s favorite flower…

With plants with strong and wide leaves, it will be easier to brush all the leaf, covering every groove. When they have many leaves, the leaves are soft and small etc., the best option is to cut as much foliage and stems as possible and only leave a few to sustain your plant and only treat those.

Basically, what you want is a manageable set of stems and leaves that you can treat individually and with care and that you can reach without obstacles.

How to use the insecticide to treat spider mites infestations

If you want a fully natural insecticide, the alternative is easy but pricey. You will need to mix one tablespoon of Rosemary essential oil for each ounce of water. For a liter, that’s about 33 spoons… But if you have no money problems, or just a small plant, it may be worth it.

Spider mites infestations are hard to treat because they hide in the “nooks and crannies” of your houseplants. You will find them hidden in grooves, folds, bumps etc. and especially on the back of the leaves and near the petiole. Some may have ventured to the stems, so, don’t forget about them.

You will need to repeat the treatment on each side of each leaf and then move to the stems. You will also need to spray the insecticide twice at every round… Also, a problem people have is how to treat the bottom of the leaf; this is easier with large and strong leaved plants, but quite obnoxious with houseplants that have soft and small leaves.

Let’s see how you can do this…

First, place the plant somewhere safe and far from other plants if possible.
Spray the top of the leaf, be generous. This will already have an effect but it is not enough.
Hold the leaf gently with your hand; put the palm of your hand under the leaf, you will need to give support to the leaf while you are brushing it; you hand needs to be like a “table”, a rigid support for you to brush the leaf.
Start brushing at the very base of the leaf, where it meets the petiole.
Brush the leaf following the groves; these go from the mid rib and the base of the leaf to the edges of the leaves. You have to brush in this direction because otherwise you will not push the insecticide in the very grooves and folds where the spider mites hide.
Leave no part undone.
Spray again, this time less abundantly. This is to make sure that all the spider mites have died. In fact, with the first spraying and brushing, while breaking all the protective webs some of the spider mites may have survived.
Now, hold the leaf up and spray the bottom.
At this stage, it is usually easier to take the plant in your lap. Use a towel or cloth if you don’t want to stain your clothes.
Holding the leaf gently and giving it support, brush the bottom of the leaf. To do this hold your hand on the other side of the leaf where you are brushing it.
Start at the petiole and base of the leaf and be particularly careful in this area.
Following the veins and grooves of the leaf, brush it all carefully. Make sure you go into curls, bumps and every cranny where the mites can hide.
Spray again, this time less generously. You may even want to brush again when treating the bottom of leaves.
After you have done all the leaves, front and back, move to the stems.
Spray each stem in turn, on two opposite sides.
Brush the stems; the stroke should go lengthways and back and forth.
Spray again, this time less generously.
Do this for each stem in turn.

For an average houseplant, this may even take the best part of an hour. As we said, it is long, detailed and laborious.

Your plant will now look very glossy and shiny. It will already look better. You can, at this stage, place it in front of a gentle fan (not a heater, not a cooler) to dry it, but it is not necessary.

Getting rid of spider mites: the high tech solution

Spider mites are such a common and devastating problem that scientists have even developed high tech solutions. However, you can only use these if you have a perfectly controlled environment (like a hydroponic factory) and lots of expertise.

The solution consists of:

Raising the temperature to 86^oF (30^oC).
Lowering oxygen to 20%.
Raising carbon dioxide (CO₂) to 60%.
All this for 16 hours.

I am sure that you can see that this is not something you can do at home, but with a high tech greenhouse you may even have the right means.

Say goodbye to spider mites

Spider mites are small but multiply very fast. They are almost invisible but they can wreck havoc on your plants. Now you know what favors them, how to recognize them and that there are ways of getting rid of them.

One is simple but only works for small colonies. The second is laborious, but for many it is the only effective solution available. The third is less labor consuming, but you need special equipment and a special environment to use it.

So, we are left with the prospect of spending long hours cleaning all our plants unless…

Unless you prevent them from coming; neem oil sprayed every now and then will do the trick.

Alternatively, a few drops of eucalyptus, lime, rosemary, cinnamon or peppermint essential oil in a spray bottle to vaporize on your plant every fortnight or weekly in the hot season will keep spider mites at a distance from your houseplants.

This way, instead of having to say goodbye to spider mites after a long struggle, you won’t even have to say hello to them.

Written By

Amber Noyes

Amber Noyes was born and raised in a suburban California town, San Mateo. She holds a master’s degree in horticulture from the University of California as well as a BS in Biology from the University of San Francisco. With experience working on an organic farm, water conservation research, farmers’ markets, and plant nursery, she understands what makes plants thrive and how we can better understand the connection between microclimate and plant health. When she’s not on the land, Amber loves informing people of new ideas/things related to gardening, especially organic gardening, houseplants, and growing plants in a small space.