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6 Causes Of White Spots On Hydroponic Leaves (And How To Fix It)

Hydroponics has become very common these days because of its high yields. More and more people are choosing this type of cultivation but often encounter some difficulties.

The main cause of white spots on hydroponics leaves is powdery mildew. It is a serious disease that infects the leaves of a plant that is not taken care of properly.

Other causes of white spots on hydroponic leaves are pests. Mites, mealybugs, and some other insects can cause these symptoms. All of these cases are described in detail in this article, along with ways to fix them.

Powdery mildew

Powdery mildew is a disease that affects many plants, including hydroponic ones. In most cases, it starts at the top of the plant but over time the whole plant becomes infected.

Small white spots appear on the leaves and stems that keep getting bigger and bigger. Then the leaves lose their green color and become dark brown.

Powdery mildew most often affects tomatoes, but any plant can fall victim to it. If you grow leafy greens or herbs and they get sick on Powdery mildew, there is no point in treating the plants because they are no longer edible. The best thing to do is to throw them in the trash.

If the disease has affected the fruit plants, then you can cure them. Examine each plant and remove the badly diseased leaves.

Next, spray the plant with neem oil. Use a ready-to-use neem oil that is designed for treating vegetables. Avoid getting the neem oil on the fruit.

You can just put plastic bags over the fruit before spraying. And remove the bags after the treatment. Also, wash the fruit well before eating it.

To avoid Powdery mildew in the future, place hydroponic plants at some distance from each other. Make sure that the hydroponics area is well-ventilated.

Also, a common cause of this disease is too much nitrogen in the solution. Therefore, when making the nutrient mixture, avoid putting too much nitrogen fertilizer.

White rust

The next cause of white spots on hydroponics leaves is a disease called white rust. The spores of this fungus get on the leaves and begin to sprout.

The first thing you may see are small white spots that will eventually turn into pustules. In addition, the leaves of the diseased plant may become deformed or even torn.

This disease develops best in a poorly ventilated and very humid place.

If white rust affects your hydroponic plants, remove the leaves on which you see white spots. If the damage is severe, remove all plants from the system to prevent further spread.

There is no point in treating the plants with fungicide as this will make them inedible. The best way to prevent this disease is to keep the hydroponics well-ventilated and to reduce the humidity around it.


white spots on hydroponic leaves


Mites are quite common plant pests. They can parasitize almost any plant.

Usually, these creatures suck on the leaves and feed on the sap of the plant. Very small white spots may appear where this happens. Over time, the leaf will turn yellow and fall off.

The problem is that the mites are very small and difficult to see. Use a magnifying glass to examine your hydroponic plants for mites.

If mites have infested your plants, the first thing you can do is spray the leaves with water. These creatures don’t like moisture and may just go away.

However, if that doesn’t work, dilute some lemon juice in water. You should get slightly acidic water. Spray the leaves with this solution and you will get rid of these pests in most cases.


white spots on hydroponic leaves


Thrips are another type of pest that can cause white spots on hydroponics leaves. They are small winged insects that hide under the leaves or inside the crown of the plant.

These pests damage plant tissues and white or light gray spots appear in these areas. In addition, the leaves may become deformed or wilted.

Take a closer look at the leaves and use a magnifying glass if necessary. If you see small insects with elongated bodies and wings, they are thrips.

To get rid of this pest you should use neem oil or an organic insecticide meant for vegetables. However, avoid getting them on the fruit.

If thrips have ruined your leafy greens or herbs from spraying is contraindicated. Take each plant and wash off the pests under running water. If that doesn’t help, it’s best to get rid of the infested plants.



Mealybugs are insects that are shaped like fairly large white dots. In addition, there is usually a lot of white cotton-like substance around their habitat. They have a rather strong armor on their backs that protects them from predators.

The food of these pests is plant sap. If there are a lot of mealybugs on a leaf, it will eventually turn yellow and die off.

If you see a mealybug on your hydroponic plant take a cotton swab and dip it in alcohol and remove it. You can remove some of the pests this way without damaging the plant.

However, if there are a lot of mealybugs, you need chemical treatment. A systemic insecticide is the best way to do this.

But the disadvantage of this approach is that the plant will become toxic to humans as a result. Therefore, in this case, it is better to throw your plant away.

Read also: 5 Hydroponic Systems for the Home


white spots on hydroponic leaves


And the last cause of white spots on hydroponic leaves can be aphids. These are very small bugs that are often white or light gray in color. They suck on the leaves and feed on the sap of the plant.

In fact, aphids are very common pests. Very often ants transport these insects to the plants.

The aphids themselves may look like white dots. They can also cause discolored spots to appear on the leaves and the leaf may curl.

There are several chemical ways to get rid of aphids, but in the case of hydroponics, it is better to use the organic method. Take each plant to a basin and wash the aphids off under a stream of water.

The second thing you can do is get ladybugs on your hydroponic plants. These beetles are the natural enemies of aphids and will kill them very quickly.