spider mites must die! Organic and better solutions to spider mites on houseplants and plants.

Let's talk about all things spider mites.  Especially in houseplants.  

I've finally figured out how to keep plants alive in my house and it's been three years since I killed a plant.  I'm so happy!  But it turns out that the cobwebs I thought were spiders were actually spider mites.  NO!!!

In the future, I'll quarantine new plants.  But until then, how do I make spider mites go away?


Let's hear your stories, problems, and solutions for dealing with these little besties.

I have been growing plants indoors and outdoors. Outdoors in Iceland is always cold for some plants, so I must grow indoors.

This year spider mites have attacked many plants in my conservatory. I tried keeping moist conditions but they are still alive. They devastated almost every bean plant (including winged beans, cow peas, runner beans, and lima beans). They are not like aphids, once they arrive, no hosing fixes the problem, the plant eventually dried and dies within a few days, very quickly. They remain alive well after the plant died. I tried spraying them with soapy water, essential oils, nothing worked.

They arrive, multiply by thousands, create a spider-net like around the stems and leaves, they are very tiny and reddish, just like mites. The leaves dry within days of their infestation. It is way worse than aphids.

What can I do to control them? Is there another plant that could repel them?

The best thing for any "pest" in a greenhouse is to be patient, and let nature take care of it. This process can also be facilitated, and that certainly could help in a place like Iceland where insects are dormant for a large portion of the year.

The best spider mite predator that I've found is predator mites. It's important to let the spider mites get so prolific that the predator mites will never be able to eat them all. There will always be eggs left behind. If there are not enough spider mites the predator mites will eat themselves to starvation and then you have the whole problem again.

It requires patience, but if you are patient nature will reward you, the cycle will find a balance, and you won't have a problem with spider mites anymore, yet you are never doing anything to prevent them. This beats the alternative by a WIDE margin. For people like yourself you can order these predator mites by mail if you wish to facilitate the process. There are lots of good places, I'd recommend finding the closest breeder to your location. A good one in the united states is Nature's Control.

Other alternatives are lavender, I've heard of people putting lavender blossoms in the bottom of a spray bottle and letting them soak for a couple days then using this on mites. Neem oil is another solution for spider mites. It is the pressed seed oil from a rain-forest tree. Not really sustainable, especially with all of the embedded energy in distribution, but it is a somewhat natural solution. The oil leaves behind a waxy residue that the bugs don't like the taste of. I'm not sure if it's edible for humans, but it has a funny taste. I wouldn't recommend using it on the fruit but it won't damage the plant if used properly.

A good Neem oil is a fine art. First off you want the pure Neem oil, it should be solid at colder temperatures. The Neem oil that you buy from the garden store is full of a ton of other things that I am not comfortable used, I would only use something that is 100% Pressed Neem Oil. Because it is solid at colder temperatures it is best to apply in a warm spray. Here's the mix for a 3 gallon sprayer:

Heat 2 gallons of water, put bottle of Neem Oil in water so it warms up as well. Put warm water is sprayer, add 1 shot of Neem and one tea spoon of a natural surfactant (like the soapy stuff you wash off of Quinoa or something like coco-wet) per Gallon water. So for a 3 gallon mix, 3 shots Neem, 3 teaspoons sufactant. Then close the sprayer and mix all of the Neem and warm water up. The surfactant breaks up the Neem (which binds together in the water because they are both strong dipoles) and the warm water speeds up the process. Then you open up the sprayer, add the last gallon of COOL water (to cool the spray to room temp so that it does not harm the plants) then spray away.

I really recommend the natural approach as opposed to spraying. If you start spraying you are always going to have to spray. It's a lot of work. If you let nature take place then you won't have to work nearly as hard. But I know everyone is not as patient as I am.

For example in my greenhouse there were aphids EVERYWHERE, you haven't ever seen so many aphids. What I did was nothing, and now there are a ton of aphid destroying larvae (that I think are hover fly larvae?) totally decimating the aphid population. I did absolutely nothing to make this happen other than letting it happen. I actually even ordered bugs from Planet Natural, but they have yet to come. And so even before they arrived nature already provided a much simpler solution. The larvae that I now have didn't cost me anything, the bugs that I'm still waiting for, $400. I think I'm just gonna be more patient next time an "infestation" arises. It's really not an infestation at all, its a bloom of bugs because the system is healthy.

Most people would have seen these worms and probably bombed the whole place for fear they were going to eat all of the plants. I watched what this creature was actually doing, and it was going around gobbling up aphids as quick as it can. And now there are probably 6 of these guys for ever square foot in the greenhouse.

The best way to control the small sap sucking mites is to maintain a high relative humidity in air. Since plant sap is mostly water, sap sucking mites have to suck and process a lot of plant sap to extract enough proteins to fuel their growth. The excess plant sap and sugars get extruded from the mite's body and its water content is evaporated away. But when the relative humidity is very high, the extruded plant sap doesn't evaporate away very fast and the mite has to stop pumping plant sap (and stop growing) or risk drowning in the accumulating plant sap it is extruding. This is why mite populations explode when the relative humidity is low, but they aren't a problem when it is very humid.

Second the humidity. A rh of 70% eliminated the need for miticides in. my greenhouse, even among extremely vulnerable species. Pot growers purportedly call them "the borg" so hold no illusions about elimination vs control.

Hi; Neem oil is the best bet, apply at nite it kills eggs & larva and interups their breeding cycle. Lady bugs released can also control spider mite infestation. neem oil can be used at the same time as it will not hurt the ladybug population. Remember that your ladybugs will leave and head back to california as soon as they are hungry,so use both. Tom

The problem with spider mites is even when you can eradicate the mites, the eggs still survive even in tiny cuttings. Some people have success with Azamax.

Otherwise you would need to do a complete shutdown, cleanup, and freeze the growspace and/or flood with carbon dioxide.

Once you have gone to all that trouble, you want to HEPA filter your incoming air and refrain from bringing seedlings in from other gardens.

Raising the humidity will certainly open the stoma in the leaves and accelerate growth, which is good. But then you are going to deal with mildew. A routine preventive sulfur burn will take care of this issue and you need to schedule this away from harvest time, giving the sulfur time to become inert.

Hello,


I have a big problem with spider mites indoors.

I grow many plants indoors in a conservatory - not only vegetables for food like tomatoes, but also many perennials, tree seedlings, collection of cactus, etc. I live in an arctic climate, only 3 months frost-free, so growing indoors is essential.

The mites seem to be killing always the same prone species (like moringa, beans, seedlings of honey locust, amaranth, etc) It's not a problem for many plants, it's a manageable problem for many species (like many tree seedlings, corn or tomatoes), but it is a deadly risk for some species like those. I keep overwintering some perennials indoors, and since the conservatory with artificial lights and pots is an artificial environment, some pests get out of control.

I tried everything against spider mites, but nothing works. Predator mites definitively do not work. Cleaning everything definitively does not work. Introducing pest repelling plants like catnip, does not deter the mites too. Tried neem, essential oils, and did not work. I am tired of reading articles on spider mites and solutions that do not work.

So, I want to know, how can I, from the Permaculture point of view, create a healthy and balanced environment with my indoor plants. I already have a lot of diversity indoors but the mites kill always the same sensitive species, those species always die to mites even if I give them the best of conditions. Plants first became speckled, then leaves dried, and then eventually defoliated plants are so much weak that die.

Any bright ideas?

I have successfully cleared red spider mites by drastically increasing humidity. They like it dry, and can't live where it's wet. This might not be achievable if you have a really big space, but I got them off my orchids by keeping trays of gravel and water under the pots, and using a mister to spray water on obvious infestations.

Good luck!

I have recently come into a mite problem, myself. I've tried soap spray which helps, and I've heard of re-potting the plants after learning about mite life cycles, and how they leave eggs in the soil. I'm getting a game plan together to try a repot and then a Neem treatment after, and keep my focus on hot pest areas until the problem subsides. I also have a stink bug around that I always put on affected plants when I catch the little guy, but I don't even know if they eat mites! Just hoping, really, plus I figure a houseplant might be a good home for it.

The problem with spider mites is even when you can eradicate the mites, the eggs still survive even in tiny cuttings. Some people have success with Azamax.

Otherwise you would need to do a complete shutdown, cleanup, and freeze the growspace and/or flood with carbon dioxide.

Once you have gone to all that trouble, you want to HEPA filter your incoming air and refrain from bringing seedlings in from other gardens.

Spider mites are performing a function, which is eliminating weak or diseased plants. If you address the underlying reason why the plants are suffering, then the spider mites won't be there.

Spider mites always appear when a plant has high levels of ammonium in the plant sap. There should be zero or very close to zero total Nitrogen in the plant.

It is an indication that the plant is failing to synthesize amino acids and proteins through photosynthesis. Once you have the mites, you will need to apply bioavailable forms of Manganese, Zinc, and Iron as a foliar spray in order to kickstart the photosynthesis process and deal with the ammonia levels.

Longer term, you need to look at things that cause such high ammonia production rates that these plants can't convert it. This typically comes from overly saturated soils and high leaf temperatures (not air temperature). Or an over application of Nitrogen fertilizers of course.

Here is an in-depth lecture on spider mites:

In a situation where you are overwintering plants in high latitude regions, the chances are that this excess ammonia situation is happening because the plant isn't getting enough light to photosynthesize for sufficient periods of time.

The plant still needs food, but when it isn't photosynthesizing food in the form of sugars, it is forced to deconstruct proteins within itself, and a byproduct of that process is ammonium.

You may need to increase the amount of grow lights you are using, or introduce some if you currently don't have them.

They used a soap,  water,  and alcohol mix.

r ranson wrote:Let's talk about all things spider mites.  

I've finally figured out how to keep plants alive in my house and it's been three years since I killed a plant.  I'm so happy!  But it turns out that the cobwebs I thought were spiders were actually spider mites.  NO!!!

In the future, I'll quarantine new plants.  But until then, how do I make spider mites go away?


Let's hear your stories, problems, and solutions for dealing with these little besties.

Spider mites are way more resistant than e.g. aphids or even spit bugs (outside)
To deal with them you need to start from the root of the attacked plant:

Spider Mites breed in infertile old soil:
- That brings us to the conclusion your soil is may be too old and your plants might now even get enough food
  which makes it weaker and so more attractable for pests.
  Re-potting is a great step to give your plants strength again and the mites might disappear.

Spider Mites can live 2-5 weeks:
If you "spray" you need to batter them for at least 6 weeks continuously every other day or so. (who actually does this?)

Predators you can count on is the Killer Mite "Phytoseiulus persimilis", who are very successful wiping out entire Spider Mite invasions on houseplants.

30 Degrees temperature need to be achieved to shorten the life span of a spider mite to one week, hence you not want to heat up your quarter that much.
12 Degrees stops the development so also this would ask for a good set of extra clothes.

Self-made solutions:
As said spider mites take more of a punch than aphids so the normal soap solution is not a solution. They might appreciate it to get a proper shower and ask for daily spraying (Joking)
You want to dissolve 20 gram soap in 1 liter hot water and let it cool down, then you mix 30 ml Spirits into it and try carefully if your plant can take it.
The high spirits content will wipe the mites out if you continue for at least 6 weeks.

Dry air is a paradise for spider mites but the humidity they not like will be peeling the wallpapers off your walls, so that's something for your greenhouse and winter garden.
Unfortunately dry air will do the rest to kill your affected and damaged plant.
You can put a room humidifier on a shelf above your plant and let the vapor roll down the plant which creates a perfect micro climate, but how to do with 10 Plants? Think of your wall papers..

Plants are not designed by nature to live in a house and that is the main issue. Your spider mites will find them and weakened by the environment your plants will be attacked again and again....

I suspect my mites came when I repotted the plants before bringing them inside for fall.  I'm never sure about potting soil from the shops and I didn't get this in a black bag in the sun for very long before using it so it might have had the mites in it.

Also, I tend to underwater my houseplants - chronically.  And the place gets cold at night and these plants don't like it so I'll be moving them to a warmer spot when I can get some lighting set up.  

Thankfully the rains have started today so the household humidity will go up.  

I found a home made spray I use that literally melts the webbing, kills the eggs and the mites and helps the soil. It works well on aphids and thrips. Apply every 5 to 7 days

2 quarts water

1/4 cup each of tea tree and peppermint castile soap, I use Dr Woods as it is thicker

1 tablespoon hydrogen peroxide I use food grade but have seen the brown bottle store stuff used but it has other stuff in it

1 cup 70% rubbing alcohol

Mix first in warmish water then add cool to fill.

I do not recommend for peppers or arugula or any plant with tricombs although it can be used prior to the tricomb stage. This worked excellent in my garden this year. We were very hot and dry and loaded with mites. Two spot, spider, cyclamen and one I could not identify. My first applications were in 3 day intervals because of the amount of mites then 5 day then 7 days and then only for aphids. It dries fast even spraying to dripping. This spray helps to inoculate your soil. I have recommended in several chats and the reporting results have been excellent.🌷

Hi Sharon et al:
I wonder if one could use just "unflavoured" Castile soap and add tea tree and peppermint oil. The soaps are pretty expensive, even at Walmart.
Has anyone played around with that?
Also, which trichome plants should we avoid? Basically anything that's hairy? That would also rule out tomatoes for example. Or are you specifically talking about something that develops resin glands later in its growth cycle?

Thanks!
Jacqui

Predatory mites and lacewings along with other predators have made mites negligible for me with no insecticide spraying. The one time in several years I noticed some damage, during a hot dry period last year, I did buy some predatory mites and lacewing larvae to boost my population and diversity. I also have tried to have small white and yellow flowers (yarrow, buckwheat,
fennel and many others) that feed the adult lacewings and other predatory insects in their adult stage. I haven’t seen significant damage this year.

Jaqi LaPlante wrote:I have recently come into a mite problem, myself. I've tried soap spray which helps, and I've heard of re-potting the plants after learning about mite life cycles, and how they leave eggs in the soil. I'm getting a game plan together to try a repot and then a Neem treatment after, and keep my focus on hot pest areas until the problem subsides. I also have a stink bug around that I always put on affected plants when I catch the little guy, but I don't even know if they eat mites! Just hoping, really, plus I figure a houseplant might be a good home for it.

A year after posting this, I have found multiple sources saying that stink bugs (and all true bugs) are predatory insects and will eat your mites! woohoo!

Ladybugs are good natural predators. Be sure they have a small water source at the base of the affected plant. You can buy a pack of ladybugs at some garden stores and keep it in the refrigerator where they will hibernate so you can introduce a few at a time.

I am new and I was trying to give Nick a thumbs up, but it looks like I gave a thumbs down and can't change it. Sorry.

William Kellogg wrote:Ladybugs are good natural predators. Be sure they have a small water source at the base of the affected plant. You can buy a pack of ladybugs at some garden stores and keep it in the refrigerator where they will hibernate so you can introduce a few at a time.

Ladybugs are definitely one of the best natural options if you're dealing with aphids or other soft-bodied pests. I've had good results releasing them in the evening after watering the plants, since they're less likely to fly away right away. Keeping a shallow water source nearby and avoiding broad-spectrum insecticides also helps them stick around and do their job.

That hydrogen peroxide and 70% rubbing alcohol recipe sounds good though my first choice would be used dish washing water.

These older threads have so much good info.

I've had pretty good results with keeping spider mites under control by regularly checking the undersides of the leaves and catching the problem early. If I'm not sure what I'm looking at, I sometimes use a plant identification app to take a closer look at the symptoms. https://botanapp.com/identifier/houseplants can identify plant problems from photos and provide care suggestions, which can be useful when you're trying to figure out whether you're actually dealing with mites or something else. I still prefer to confirm the diagnosis before treating, though.