Nearly every gardener will encounter spider mites at some point in their lives. Spider mites are one of the most common pests to indoor houseplants — and occasionally outdoor plants as well. Most gardeners will only discover spider mites when they find white webbing on the leaves and stems of their beloved plants. Spider mites can be devastating to plants, but they are not unstoppable. Read on to learn more about these bad neighbors and what you can do to discourage and eliminate them.

What Do Spider Mites Look Like?

Spider mites are exactly what they sound like. Like most other mites, they are tiny arachnids, related to larger spiders and ticks. Most spider mites spin webbing on the leaves and stems of their host plant.  They are so microscopically small that it is difficult to tell that you have an infestation on your hands until you see the black spots and webbing on your plants. 

Spider mites don’t spin webs to catch bugs. They do it to extend their colony and to attach their egg sacks to the plant itself. The egg sacks are clear like droplets of water, at first, then gradually turn more solid tan in color before hatching as the young develop and mature.

Rather than eating other bugs, spider mites stab at the under layers of plants’ leaves. With their tiny, puncturing mandibles, they suck the sap directly out of plant’s leaves like a vampire. The leaves, once a healthy green, will start to turn yellow with brown, circular splotches, and the leaves will crumble to dry husks of their former selves until all you have are stalks.  The plants initially appear to be wilting from a lack of water, but in fact, spider mites are draining water directly from the plants’ veins.

There are many varieties of spider mites. The most common of which are the two-spotted spider mite and the red spider mite. (My old alma mater has a pretty good page about spider mites). Not all varieties spin webs, but a majority of them do. Webbing on plants remains the easiest way to tell that your plants are infested with spider mites.

Which Plants Are Susceptible to Spider Mites?

You will generally find spider mites more indoors than outdoors because indoor air is often drier than air outdoors. As such, houseplants of all kinds are susceptible to spider mites.

Succulent plants like herbs and vegetables are the most vulnerable. Tropical houseplants typically have a waxy membrane over their leaves that makes it difficult for mites to attack them. I have found spider mites on a variety of different plants including a miniature rose bush, basil, mint, and my Thomas Jefferson cayenne pepper plants.

How To Prevent Spider Mites

Spider mites thrive on plants already in distress, such as plants with dusty and dry leaves. So, it’s beneficial to mist your plants occasionally with a spray bottle to keep the leaves clean and fresh.

Dehydrated plants will also attract spider mites since your plants will have their stomata more open to draw moisture in from the air. This invites these pests to a veritable feast on your plant’s leaves. Keep your plants well watered to help avoid attracting spider mites.

You may also mist your plants with water infused with lemon, or garlic, or mint. These stronger scents repel all kinds of spiders. Place lemon peels, garlic cloves, or bruised mint leaves in a spray water bottle and allow the natural oils to infuse the water for a day or so. Then, mist the leaves of your plant once every other week to deter these and other pests like them.

How To Get Rid Of Spider Mites

Once these vampiric spider mites get a hold of your plants, you’ll want to get rid of them immediately. There are several methods of getting rid of mites naturally without harmful chemicals that will hurt the affected plants. 

Spider mites are a lot like aphids, cabbageworms, and fungus gnats in that they have soft bodies. These soft bodies take in oxygen from the air. So one way to kill mites is to coat them in liquids that asphyxiate them. The idea is to coat their soft bodies and suffocate them.  The methods below are all variations on this theme.

Whichever of these applications you choose, apply them to the whole plant including the undersides of the leaves and the plant stems.  The leaf undersides are where the vampiric spider mites like to hang out while they’re drinking the blood of your plants. Plant stems will harbor egg sacs attached to webbing. You’ll want to get rid of both areas to save your plant.

Dish Soap

Soap is a good way to deal with a variety of insect infestation, however, the same dish soap that you use to wash your dishes should NOT be used to cleanse your plants. Dish soap has a bunch of other additives that are good for washing dishes, but harmful to plants. Instead, look for Castille soap.

Castille soap is 100% plant-based. As such, it’s safe for plants. The soap will suffocate the spider mites and clean the leaves of the dust that attracts them. Squeeze a couple drops of Castille soap in lukewarm water. Pour this solution into a spray bottle and spray your plants.

Neem Oil

You can also use a commercially available organic solution called neem seed oil. Neem oil is a natural oil from the seeds of the neem tree, an evergreen found in the Indian subcontinent.  It is an oil which suffocates the spider mites and has a pungent scent which they hate, though I think it smells like oranges.  Use it in a 1:4 ratio of neem oil to water to reduce the danger of burning your plants. If you spray this indoors, you’ll need to clean your walls and windows of the goop. Not fun. So do yourself a favor and take your indoor plants outdoors to treat them.  Before you bring them back indoors, wipe down the area where the plants had been sitting with a damp cloth of soap and water to make sure you’re not risking a re-infestation.

You can also rub the oil on your leaves and branches with a paper towel, but this may prove to be less effective due to how hard it may be to get into the nooks and crannies of your plants.  Treat your plants in the early evening before the dew falls, if you can, or a couple hours before it’s going to rain. You’ll knock down the infestation and you’ll save your plants. 

If you apply neem oil in the heat of the day, especially in the summer, your plants will burn in the sunlight.  The oil will essentially act like a magnifying glass to the sun’s rays and scorch your beloved plants.  If it’s not going to dew or rain, rinse your plants off with a spray of cool water from a garden hose or another spray bottle a couple hours after you apply the oils to wash away both the oils and the dead husks of spider mites.

Rubbing Alcohol

You can also use a paper towel soaked in rubbing alcohol to wipe down the leaves.  When rubbing alcohol makes contact with the soft bodies of spider mites, it does the opposite of the oil, it essentially dries them out.  In effect, this method does to the mites the exact thing they’re doing to the plants.

After Treating for Spider Mites, Care For Your Plant

Depending on how long spider mites have been drilling into your plant’s leaves, mining your plant for nutrients, you may or may not be able to save your plant.

Your affected plant has just undergone a huge ordeal, both from the mites and from the gently caustic treatment you used to get rid of them. Once you’ve finished treating your plant, make sure to rinse your plants with water to wash away the solutions. Your plants have been dealt a hard blow already.  Don’t complicate matters by cutting off their ability to breathe too.

Once you’re sure your plant has been sufficiently rinsed, give your plant a little tender loving care with some fertilizer and water to help it perk back up and start growing some new leaves.

Conclusion: Not A Death Knell

If you catch the infestation early enough, you can save your plants from spider mites. If you follow these techniques, or know of others that might help too, leave a comment and let me know!