Pests - Spider Mites - A-Grade Hydroponics

Pests - Spider Mites

What are the signs to look for?


Spider mites are very small, but they do leave behind very easy to identify marks on the leaves of plants, they puncture the plants cells and suck out chlorophyl, so if you notice lots of white dots almost pinprick in size then check the underside of the leaves and in the nodes of the plants and you should see tiny speck like critters that have started to form tiny webs.

Most hydroponics grow rooms or grow tents in humid areas will at some stage encounter these pests so its worth doing the checks early on before its too late to control or spray. 

At the bottom of this blog is the spray protocol. 

What are spider Mites?

Spider mites belong to the subclass Acari mites and are smaller than 1mm in size and vary in a range of colours. Spider mites are a part of the Tetranychidae family which includes over 1000 species.

There are many different mites but only a few are common to specific plants including, two spotted mite, hemp russet mite, broad mite, black spotted mites, red spotted mites and oriental mite.

Spider mites mainly sit on the underside of the leaf making them very hard to notice until the infestation is bad enough that the mites have spread all over the plant, making them clearly visible from a small distance to the human eye.

If your plant appears to be suffering for unknown reasons, inspect your plants thoroughly to ensure there isn't an infestation of these mites, as most people overlook this.

Spider mites thrive in warm conditions (preferably around 27°C), which is why they are more common indoors, searching for an ideal environment to breed and live in.

A female spider mite can live for approximately 3-4 weeks, laying up to 20 eggs per day once sexually mature (they are sexually mature from 3-5 days old!)

A single female spider mite can lay close to 500 eggs in her life cycle.

The eggs are transparent and minuscule and will hatch within 3 days, they have a hard outer shell to protect the eggs from attack.

If spider mites are not noticed within a couple of days after noticing health problems they can take over your grow room within a week easily, as the mites have an ability to down-regulate the immune response of a plant.

Spider Mites pests

To get rid of these nasty little pests, I like to make up an organic spray to deter and kill them in the growing area. 

Add teaspoon of dishwashing liquid.

Add Pyrethrum and Mite-Rid in dosage rates on the bottle.

Add contents into 1L spray bottle.

Once you have made the spray, mist the undersides of the leaves until saturated. You want to do this at least 2 times per day once in the morning and once at night, ensuring your ventilation system (if you have one) is switched off, the idea is to permeate the room. Ventilation systems should probably stay off for 45 mins.

Keep spraying for around 5-7 days this should interrupt the spider mite’s life cycle and hopefully rid your plants of these pests!


> Propagation
> Hydroponic Equipment
> Plant Nutrition & Health
> Hydroponic Environment
> Harvest
> How To...
> Geek Out With A-Grade
> Water Control
> Plant Training
> Grow Medium
> Troubleshooting
> Hydroponic Basics

Other Tutorials

Managing Thrips in Your Grow Room
HLVd - Hop Latent Viroid Disease
Fungus Gnats 101
Hydroponics - Fungus Gnats
Pests - Spider Mites

premium hydroponic store

We're committed to helping communities in Australia grow
Shop now