How to get rid of Spider Mites fast
Thank goodness Spider Mites are barely visible with the naked eye, although that's the only good thing I have to say for these common creepy crawly plant pests. Spider Mites suck, both figuratively and literally. They feed by sucking the fluid out of plant cells on leaves and flowers.
Also known as the red spider mite, clover mite, cyclamen mite and two-spotted spider mite, these bugs vary from almost translucent to yellow, green or red, usually with dark patches on their sides. Not that knowing what they look like helps much! But being able to spot the signs before it gets too bad for your plant to recover, and how to get rid of them if your plant does have spider mites, is what counts...
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What are the signs a plant has spider mites?
Leaves mottled with small dots and a very fine webbing (much finer than a spider web) are the visible signs of spider mites. The mites themselves are barely visible but you might see them moving if you have great eyesight or a particularly bad infestation.
Their webbing is often the first sign you'll see. The dots on the leaves may be white to pale yellow or dark red to brown, caused by their needle-like mouth parts that pierce the leaves to feed on individual plant cells. The dots are normally visible on the top of the leaves, especially newer softer foliage that hasn't hardened off yet, although the mites are actually feeding underneath the leaves.
[above - their very fine webbing is often the first sign of spider mites]
What conditions do spider mites like?
Hot and dry is an ideal combo for Spider Mites, hot, dry and dusty is even better. If you've been given the advice that simply keeping your leaves dust-free can help prevent pests, the pests they're most likely talking about are spider mites, and products like neem-oil based leaf shine certainly do help ( if you're NZ-based, my go-to is Plant Runner Neem Oil Leaf Shine).
Are some plants more prone to spider mites than others?
Yes, some indoor plants are much more prone to spider mites than others, especially thinner-leafed plants. Under-watered plants are also easier targets. Dusty foliage and plants kept in dry air conditions also puts out a welcome mat for spider mites as they prefer low-humidity. They are also attracted to the light, so plants in brighter light appeal more.
The list of plants more prone to spider mites include: alocasia, calathea and maranta, palms in general, ivy, philodendrons and ficus (but they aren't picky, spider mites can set up home on any indoor plant in the right conditions).
Where do spider mites come from?
Spider mites are more mobile than you might think. You may have bought an unwelcome guest back with you last time you visited a garden store - and not necessarily on a plant either - even your clothes brushing past an infested plant can be enough to bring spider mites home.
Putting your indoor plants outside - even for a short time - can be like putting out a vacancy sign. Even an open window could be enough for a spider mite using its web for a little float-and-see. Spider mites can also stay in the egg or adult female stage over winter and start the cycle all over again when conditions are right in summer.
How to get rid of spider mites on houseplants
STEP ONE: SPRAY N WIPE
The first thing to do when you suspect spider mites is to isolate the infested plant/s. Then you want to 'spray n wipe' by using the shower or a spray bottle to wet then wipe the plant as thoroughly as possible. You want to manually remove as many mites (and their webs and nests), as you can before you treat them. Make sure to spray n wipe all of the plant - just with water is fine at this step - not forgetting the bottoms of the leaves where they mainly feed.
Treating with an insecticide without first 'spray n wiping' the plant can result in the treatment not working properly as their nests and webs give spider mites an extra layer of protection.
STEP TWO: CONTACT INSECTICIDE
There are two common ways to treat spider mites. With a contact insecticide only, or with a combo of contact and systemic insecticide. Some people only spray with a contact insecticide (four options coming up below). However if you only use a contact insecticide, you'll likely find you need to isolate and repeat treat for longer, because spider mites have such a fast life cycle in good conditions (as fast as one week!). More coming up about the optional step three, which is to use a systemic insecticide after a contact insecticide.
Best insecticide treatments for spider mites
For the best insecticides that instantly kill spider mites on contact: two DIY options are rubbing alcohol or insecticidal soap and two store-bought options (both available in New Zealand), that I've used are Enspray 99 or BioNeem.
A quick word of caution when it comes to neem oil products however. Most are NOT tested or proven insecticides. That's why you'll often hear people saying 'neem doesn't work'. It does! But you need an insecticidal neem that is higher in the active ingredient that actually kills pests. Some neem products are great as a leaf shine or mild repellent, but not the natural killing machines companies like to claim they are. The one I use (BioNeem, linked above), is a proven, tested insecticide.
Best home-made DIY treatment for spider mites
If you prefer the home remedy / DIY method for spider mites, two popular treatments are to spray on then wipe down the plant using either undiluted rubbing alcohol by itself, or for sensitive plants, make your own insecticidal soap (my recipe's below).
WARNINGS - Plead read before any treatment
Since the home remedy / DIY method isn't a tested, store-bought mix, this isn't an exact mixture that is guaranteed to work without harm to your plant. If your plant is sensitive, or you're unsure, when using ANY treatment, first spray and wipe down the plant using water. Then start with my mix in the following ratio below, but spray and wipe on a small area of the plant at least two days before treating the rest to check for a reaction. Some products may recommend waiting longer before treating the rest of the plant (check the label).
If using rubbing alcohol, you want a mix that's 60% to 70% alcohol, not 100% or you'll more likely damage your plant along with the pests. The one I use on my plants is linked below.
Even a very safe or natural or organic insecticide can still damage a weakened plant since it's under attack by pests already. Many insecticides - both DIY and store-bought - are more likely to harm a plant if that plant is under moisture-stress, such as under-watered or kept in very dry air conditions. Fixing moisture-stress first will help combat spider mites AND help protect your plant from insecticide damage.
Which rubbing alcohol can be used on plants?
I use (and sell) this brand: Isocol Rubbing Alcohol (available in New Zealand), which is 64% isopropyl alcohol, but you can also get rubbing alcohol from your chemist, hardware store and some supermarkets. If you're not in New Zealand, Whole Foods Market 70% Isopropyl Alcohol is another good option that's easy to find online (that link takes you to Amazon), and in-stores. Just make sure you check the label before you buy. Some brands still call it 'rubbing alcohol' even when it's over 70%, but keep in mind the dilution rates below are based on using maximum 70% alcohol.
My DIY insecticidal soap recipe for spider mites
I use about 2 parts rubbing alcohol to 5 parts water, then add a teaspoon of liquid dish soap and stir. You can spray on or wipe on the mixture. Make sure to include the stem and underneath the leaves, not just the top of the leaves.
Spraying on with a super fine 360 plant mister is best as they spray upside-down and also help make sure the plant is entirely covered as the droplet size is much smaller than normal plant misters. If you're not in New Zealand, get yourself one of these hairdresser super fine misters which are similar to the 360 misters. I normally leave the mix on for 15 minutes, then wipe it off, using a cotton pad for the top and underside of the leaves, and a cotton bud or ear bud for the crevices.
A less manual option is to spray the mixture on to foliage and stems, top and bottom of leaves, using a super fine mister for really good coverage. Leave it on the plant for 1 hour, then thoroughly rinse off the dead mites with plain water. A high pressure shower is best for rinsing as you want to make sure you've washed off all mites possible.
What type of liquid dish soap is ok for plants?
When using dish soap on plants, plain liquid soap without scents or other additives is best. Pure castile soap is often recommended for plants for that reason. Dr Bronner's is probably the best known brand of pure castile soap and is available in New Zealand from most chemists and whole food stores, or for my international plant friends you can get Dr Bronner's Pure Castle Soap Unscented on Amazon too.
How often do you you need to treat spider mites?
Whether you go the DIY route with rubbing alcohol or insecticidal soap, or store-bought, keep in mind they are a contact insecticide only, meaning to kill they need to be in contact with the mites. That means you'll need to repeat the treatment a few times. Ideally every 3 days for at a minimum of 2 weeks, but if using a store-bought product, follow what the label tells you. I would then isolate the plant for a further 2 weeks following the last treatment and inspect thoroughly for new webs or leaf damage before returning it to its usual spot with the rest of your jungle.
STEP THREE: SYSTEMIC INSECTICIDE
If spider mites keep coming back or you want to do the best job possible to make sure they don't, follow up with this optional third step, which is a systemic insecticide. A systemic stops spider mites getting established again by working from the inside of the plant and kills newly hatched spider mites when they start to feed (the ones that a contact insecticide can't kill).
A systemic gets into the system of the plant and depending on the product, it can either be absorbed through the foliage or through the roots. For spider mites I prefer using the type absorbed through the leaves as it works faster (great for pests like spider mites with very short lifecycles), and it targets where spider mites prefer to feed (the leaves).
Also keep in mind spider mites can build up resistance to treatments, so you're best to do it right the first time with a thorough treatment following all three steps. Repeating the same systemic could mean you end up with it not working and having to resort to the more manual step of using contact insecticides repeatedly or finding another systemic to try (and there are far fewer options for systemics than for contact insecticides).
Best systemic insecticide for spider mites
My go-to is Groventive (that one's available in New Zealand), which is the spray-on type, or for my overseas plant friends, you've got Bonide Systemic available on Amazon which is the type you water in via the roots.
How to apply a systemic
First do steps one and two above (spray and wipe with water, then with your contact insecticide of choice), before you apply your systemic. If you have a look at the directions for Groventive, you'll see you can save time by applying Groventive mixed with BioNeem or Enspray 99 (that link gives you the dose and directions depending on which product you're mixing it with vs using it by itself).
However, I wouldn't mix Groventive with insecticidal soap or rubbing alcohol, so best to stick with store-bought and tested combinations when combining a contact and systemic together (as Groventive has been tested with both BioNeem and Enspray 99). Whatever systemic you use, always follow the directions to the letter, as you want to avoid the pests building up resistance.
How to prevent spider mites
Knowing the conditions spider mites love - and doing the opposite - is the best way to prevent spider mites. Using a systemic as a preventative isn't recommended as they can become resistant. in general you want to avoid moisture-stress for your plants, which puts out a welcome mat for spider mites. Keep them watered at the moisture level they prefer. Don't leave them dry too long. Avoid dry air (use a humidifier if needed). And keep leaves dust-free.
I'm sorry you've had to read this guide, since it likely means you've got spider mites to contend with, but I do hope it's given you a few options for treatment and the tips to make sure you're spider mite free in just a few weeks.
Happy (bug-free!) growing,