How to Keep Bugs Off Indoor Hydroponic Plants?

Hydroponic plants generally have a low risk of pest infestation compared to plants grown in soil.

However certain conditions like high humidity, high temperatures, improper nutrient concentration, pH changes, lack of ventilation, etc invite bug infestations.

It’s important to prevent their attack and even more important to know how to deal with them once they arrive.

Read on to know all about how to keep bugs off your hydroponic indoor plants.

The most common type of bugs found on hydroponic plants

If you want to keep bugs off hydroponic plants, you need to know their types. These are some of the most likely bugs


They are pear-shaped and black, green, or greyish. Weak and stressed plants are susceptible to them. Excess of nitrogen in the nutrient concentration is an attraction for these bugs.

Aphids suck sap from all the parts of the plant and are most visible along the stem.

They also secrete honeydew when they are feeding that attract ants. The plant starts turning yellow and crinkled.

Also read: How to Kill Aphids on Indoor Plants?

Spider mites

They look like spiders but are minuscule in size(less than 1mm in length). Spider mites are red, green, or yellow. They are mostly found on the underside of leaves.

They create fine webbing on leaves and stems.

Spider mites infest plants in high temperatures, dryness, and low humidity. They cause dehydration and weakening of the plant by sucking up its juices.

Spider mites leave yellowish whitish spots on leaves where they feed.

Also read: How to Get Rid of Spider Mites on Indoor Plants?


These are tiny white flies about 1mm in length.

They suck on the juices of the plants leaving behind honeydew that breeds a fungal mold. There is also discoloration in the spots that it’s been feeding on.

Whiteflies can be found on the underside of the leaves.


They are tiny insects around 5mm and can be yellow, brown, or black. They show up as groups. Thrips love to feed on flowers and buds.

They are attracted to light-colored flowers and plants.

They cause the areas where they suck plant juice to become dark and brittle. Some Thrips tend to insert their eggs inside the stem and leaves


Mealybugs suck juices from the plants leaving behind a honeydew residue.

They are attracted to fruiting plants. They are small bugs and have a waxy coating.

Mealybugs leave eggs as white cottony masses mostly in the undersides of leaves and stems.

Fungus gnats

They are tiny gray-colored flies. They do not do much harm. However, their larvae, that look like white translucent maggots, eat up the plant’s roots. The larvae also feed on algae around the base of the plants.

Fungus gnats give rise to bacterial infections. The plant starts looking wilted and develops yellow leaves.

Let us now understand how to deal with the bugs once they appear

How to Remove the Bugs from Hydroponic Plants

Bugs can be taken care of by correcting the environment, pH and nutrient solution, etc. However, some bugs can be persistent and should be removed with the help of chemicals.

Try organic methods and avoid strong chemicals so the bugs don’t get immune and the harsh chemicals do not harm the plant.


Aphids secrete honeydew which is the sticky residue that leads to the growth of sooty mold. They can be of any color.

A decrease in feeding will help. Use Predator bugs like ladybugs to control aphids.

Severely infected parts may need to be removed. Aphids mainly come from outdoor gardens and landscapes.

Make sure to sterilize everything brought from outside and also to seal the growing area from outdoor gardens.

Spider mites

Spider mites weave fine webs. They also leave whitish yellow spots on areas they feed. Prune away the heavily invested parts.

Use a safe organic insecticide or pesticide like pyrethrin. Another example being Neem oil that can be sprayed every few days.


Whiteflies also leave a sticky honeydew on the leaves like aphids. The area where it has been feeding will have light discolored spots.

Spray the plant with good pressure with a hose. Introducing Predator bugs like ladybugs, lacewings also helps to get rid of them.

Scrape off the eggs from the underside of leaf surfaces and stems. Organic insecticide like neem oil can be sprayed every few days.


Thrips will appear as black spots on the leaves that are feces. A plant infested with thrips will also have discolored spots and the plant will appear dry.

Natural predators that harm thrips like minute Pirate bug are very effective. Ladybugs and lacewing bugs are also good predators for Thrips.

If the infestation is huge, pyrethrin can be used followed by an insecticidal soap solution. The insecticidal soap washes away the protective coat on thrips. Sticky traps are also quite useful in catching the thrips


Mealybugs have a waxy coating and leave behind honeydew residue much like Aphids. They are most commonly found on the underside of leaves stems. Their eggs appear as white cottony clumps.

An insecticidal soap solution and Predator ladybugs are good solutions to get rid of mealybugs. Organic pesticides/insecticides are also quite effective. Make a Neem spray solution and spray every few days.

Fungus gnats

The adult gnats fly up whenever there is a disturbance. Their larvae can be found in the growing medium by turning the medium over. Fungus gnats love a wet environment so dry up your growing medium as much as you can.

Catch the eggs with sticky traps near the medium. Predator nematodes will also effectively remove the larvae.

Use an organic combination of Neem oil + pyrethrin+ soap solution every few days to eliminate the adults. If the larvae/eggs are in thousands, discard the plant right away.

Let us now see how to keep bugs away from hydroponic plants

How to Keep Bugs away from Hydroponic Plants

There are are some safety methods we can follow that can help keep the pests from attacking the hydroponic system.

Let us deal with them one by one.

Keep the growing area clean and sterile

The people growing and nurturing the hydroponic plants can help the transfer of bugs and bacteria from their bodies to the plant area.

It is a good idea to wear clean and sterile clothes with gloves before entering the growing area. keep the area clean and also sterilize your tools or anything else that you bring inside for plant care.

Make sure you keep the hydroponic system pots and pipes clean and sterile.

Control the temperature and the ventilation

Most of the bugs are attracted to high temperatures and weak plants.

Make sure to keep the growing area well ventilated while also taking care of the seals of doors and windows. This will take care of pests from outdoor vegetation.

Certain pests like spider mites and fungus gnats find an ideal environment in low humidity. Keep a balance in humidity preferably at 50 %.

Healthy growing medium

Make sure the growing medium you purchase for your hydroponic plants is of good quality and sterile.

Many bugs inadvertently enter via unsterile and infected growing mediums. Some examples being coco coir and rice husk.

Check the new plants

This is the most important precaution and often ignored.

Make sure to thoroughly the check new plant. It is a good idea to keep the plant in isolation for some time and check for any bug infestations. Once you are sure there are none, keep it inside along with other plants.

Here is a quick brief on how to check if your plant is infested with bugs.

Check for discoloration

Most of the bugs suck nutrients out of the plants.

You will find tiny holes that are discolored or yellow in the places where the bugs have sucked juices.

Check for spots

The bugs are tiny and can hide pretty well in the plant. Check carefully for spots that could be eggs for feces or honeydew. The color of the spots could be yellow, brown, white, or black.

If the spots can be removed with your fingers then there are bugs on the plant

Check for holes

As the bugs suck liquid from the plants they leave holes that are tiny and raised surrounded by a yellow or white area.

These holes are different from burn holes due to excessive sunlight.

Organic pesticide spray

Every once in a while, spray your plants down with neem oil+soapy water. This will prevent any bugs from settling down and infesting your plants.

You can also use a strong jet of water with a hose to wash them down and naturally dry. Plants love these occasional treats and will respond by looking happy and healthy.


The bottom line is that these are the few bugs that you can encounter when growing plants hydroponically.

Everything cannot be perfect always and there are bound to be lapses while growing and nurturing hydroponic plants.

However, now that you have good knowledge of how to prevent and deal with them, you have the power to make sure your plants will be fine. Good luck!

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