If you’re already a gardener or a houseplant enthusiast, you’re probably familiar with the dread of finding a spider mite infestation. Spider mites are common in most places around the world (though species will vary), and these ultra-fast-reproducers give even rabbits a run for their money. These pests are not to be taken lightly – in less than a week, a spider mite colony can do a lot of damage and become large enough that they’re difficult to combat. The good news, is that all hope is not lost!
Why They’re Good
Outside of providing food for the beneficial insects that we like to cheer on (ladybugs, lacewings, and more), most herbivorous species of spider mites are quite simply, plant enemies.
When They’re Bad
Pretty much always! If you spot spider mite evidence (see below) on your plants, even if there are only a few tiny mites, you can count on having an infestation soon. Spider mites hatch and mature to egg-laying capabilities in as little as 3 days, and they can live for weeks. This means that the population grows quickly and exponentially. These small-but-mighty pests feed on our plants in a way that quickly destroys leaf tissue, which can stress or kill a plant in a relatively short period of time.
While some insect pests just cause cosmetic damage, spider mites can quickly obliterate your favourite houseplant or garden producer, and can easily spread to other plants. As cousins to the arachnid family, spider mites use breezes to drift on their delicate webs, will often hitch a ride on a household pet, or even latch onto your clothes or skin (ew) for a quick ride.
Where & When You’ll Find Them
Spider mites climb upwards, as a rule. You likely won’t find them around the base or soil of a plant (if you’re noticing fine webbing on the soil, it’s probably a tiny, harmless spider species, not a mite). Instead, you’ll find them near the top of the plant, congregating along the creases and veins on the top of a leaf, in tiny crevices where the leaves and stems meet, and sometimes even on the underside of leaves.
Spider mites thrive in hot and dry conditions. They’re powerful as an unhampered colony, but they are wimps when it comes to the elements. Rain, wind, humidity and cold temperatures are enemies of the spider mite, which is why houseplants tend to be more susceptible to large spider mite infestations than outdoor plants. In your garden, you’re more likely to notice spider mites during the hot, dry months of the summer (July, August), but in your home, spider mites can become a problem anytime.
How They Impact Your Plants
Spider mites use their microscopic, tubular mouthpieces to puncture the leaves of a plant and feed on the nutrients and chlorophyll stored in the plant tissue. Over time, those leaves will show puncture marks, turn yellow, white, and eventually brown, before they dry up and fall off. As the population grows, this damage destroys plant leaves one-by-one, and if left unchecked, can kill the whole plant.
In addition, spider mites cast a fine webbing around the leaves and stems of a plant that is meant to protect their eggs. In large quantities, this webbing prevents the plant tissue from getting enough sunlight, or from perspiring or ‘breathing’ properly, which also leads to yellowing and tissue death.
Identifying Spider Mite Damage
Spider Mites are ultra-tiny, so you might have to look close to spot one in action. However, they leave behind the tell-tale ‘spider mite’ dust, and cause an identifiable yellow or white mottling on the leaves they are affecting.
You may notice that there is a fine white dust covering the leaves of your plant near the top, usually concentrated along crevices and vein pathways of the leaf. This ‘dust’ is actually made up of spider mite poop, dead mites, and live ones. The most mature adults may be large enough for you to notice movement on the leaf.
Another classic spider mite sign is fine webbing connecting the tip of the leaf to the underside, across tiny ‘leaf canyons’, or around joints on the plant (where leaf meets stem). The amount of webbing is directly related to the maturity of the colony, so if you’re noticing a lot, it might be time to declare war.
How to Deal With Spider Mites
Ok so this is key: With spider mites, it’s particularly beneficial to use natural solutions first – spider mites are known for
their adaptability and quick reproduction. Not only is it possible for a colony to develop a tolerance for pesticides, but these pesticides can also kill beneficial predators that might be living with your spider mites in your outdoor garden (unbeknownst to you).
If you’re introducing a new houseplant to your collection, it’s HIGHLY recommended that you ‘quarantine’ that new plant for about a week – simply keep it in a location where it is separated by a significant amount of space from other plants. Spider mites are super common, and thrive in most indoor conditions, so this gives you time to notice any evidence before accidentally creating a spider-mite-pandemic in your home.
If you’ve noticed that a new spider mite colony is making an unwelcome appearance, we recommend trying these remedies in this order (or skip ahead based on severity):
Cut Off Suspicious Leaves: If your plant has enough healthy grow to manage it, of course. Typically, spider mites will start by concentrating on one or two leaves. If you catch them early enough, you can quickly solve the problem by simply removing them from the plant.
Rinse & Wipe All the Leaves Down: Spider mites hate water. Plus, your hand is physically impossible for them to combat. If you can, spray your plant down with a hose, rinse it in the sink, and use your hand and a cloth to physically wipe the leaves clean of their unwanted guests.
Bag It: Spider mites love hot and dry, so make it a high humidity environment! Mist your plant thoroughly with water, and cover the plant with a large, CLEAR, upside down plastic bag, sealing the bottom by tying it around the base. This will create a high-humidity mini-greenhouse in which the plant can still get sunlight. Within about a week or two, the spider mite colony should drop dead as a result of the moisture. Over this time, keep an eye on your plant to make sure it’s handling the humidity ok.
Insecticide: As a last resort, you can use a miticide such as End All or Safers Insecticidal Soap to coat your plant. Be sure to cover all leaves and stems well, including the underside of the leaves. Check your plant every other day for a few weeks and re-apply at the first sign of live spider mites.
What About Other Bugs?