Basil Plant Leaves Turning Yellow In Aquaponics – Diagnose Like A Pro!

Last Updated on November 13, 2022 by Guillermina

Why are my basil plant leaves turning yellow in aquaponics? If you are an avid gardener, or just a lover of plants, you know that leaves turning yellow is never a good sign. In this article, we will attempt to troubleshoot the issue of basil plant leaves turning yellow in aquaponics.

Why Are My Basil Leaves Turning Yellow?

Ocimum basilicum, commonly known as basil is a very popular herb that is commonly used in many dishes. If you love your cooking then you probably have this herb growing on your window sill or have a bush just outside your kitchen door. Basil is from the same family as mint, the Lamiaceae family. It originates from India, the land of spice and has spread to other parts of the world where it is much loved.

While this herb grows well in soil, it also makes an excellent aquaponics crop if paired up with the right fish. Whether grown in the soil or in aquaponics, basil leaves can turn yellow. If you want to keep your plant alive, you will have to correctly diagnose the cause so you can remedy it. So let us look at possible causes in an aquaponics system.

What Causes Basil Leaves To Turn Yellow?

There are various reasons why your basil leaves can turn yellow.

 "why are my basil leaves turning yellow

The possible first cause of basil plant leaves turning yellow in aquaponics is pH. In aquaponics, you often face issues such as pH imbalance. Plants have a pH preference that is ideal for them, and this varies between plants but the range is usually between 5.5-7.0. At this ideal pH, plants are efficiently able to absorb nutrients from the water. If the plant can’t uptake nutrients, it can lead to nutritional deficiencies which may present as yellowing of the leaves. So keep your aquaponics pH between 5.5 and 6.5 to avoid your basil leaves turning yellow.


pH is more of a problem in aquaponics that in soil. This is because soil has a natural ability to buffer against pH changes. This means that the soil will correct for any changes in pH to suit the plant. Water, like in an aquaponics system does not have this ability, so we have to correct for pH changes. To lower pH, acids such as nitric, muriatic, and phosphoric are used. Calcium carbonate and potassium carbonate are used to increase pH.

Nutrient Deficiency

The second possible cause is nutrient deficiency. If you have checked your pH and it is at the ideal range for basil, the yellowing of your plant leaves could be due to nutrient deficiency. Basil requires a fair amount of nutrients to grow well and remain healthy.

Provide your basil plants with a nutrient solution that is high in nitrogen and see if the yellowing does not go away. You will need to be careful however that the addition of extra nutrients in your aquaponics system does not overwhelm your filtration system, and does not kill your fish.

Bacterial and Fungal Infections

Disease infections can also cause your basil leaves to turn yellow. Infections with pathogens such as basil mildew which is caused by Peronospora belbahri. The best way to deal with this issue is first to know how to identify the symptoms. Once you know them you can remedy the situation.

Ways of avoiding the spread of the infection involve preventing the wetting of leaves because this pathogen thrives in wet and humid conditions. Prevent water from splashing onto the leaves of your basil in your system. Reduce humidity in the area where your system is. This should help prevent the problem. It is also important that you use disease free seedlings to plant in your system because once an infection spreads, it may become difficult to contain.

Bacterial and fungal infections which thrive in wet and humid conditions can also cause your basil leaves to go yellow. These include those caused by Pseudomonas cichorii and Podosphaera xanthiiThe best way to minimize the risk of these infections is to reduce moistre and humidity in the environment where your aquaponics system in located.

 basil plant leaves turning yellow in aquaponics

Natural aging

Natural aging of your basil plant can cause yellowing if the plant leaves. This happens when the plant has completed its life cycle and has reached the end of its life.  In this case, the is no remedy. You just need to accept the plant’s time is up. It does not need to be a sad occasion as you can simply get a new, productive plant to replace the old one.

Unfavorable Growing Conditions

Unfavorable growing conditions will negatively affect your basil plant and this can manifest in the plant leaves turning yellow. If the temperature, light intensity, temperature, and nutrient provision are not ideal, your basil will surely suffer. Provide your plant with the best growing conditions to prevent this problem from occurring.

Can You Eat Yellow Basil Leaves?

Now that you know the possible causes of basil leaves going yellow. You are probably interested in knowing whether the yellow leaves are safe to eat.

Basil plant leaves turning yellow signify that something is not quite right with the plant as this is not its normal healthy colour. While the yellow leaves of a basil plant are not poisonous in any way, they may have an unpleasant taste due to to the stress that the plant is undergoing.

How To Save My Basil Plant

You have probably heard the phrase, prevention is better than cure. This phrase holds true for saving your basil plants. Stresses plants, due to unfavourable conditions become susceptible to a wide range of diseases and infections.

The best way to save your basil from any effects of environmental stresses is to provide it with the best growing conditions.

If however you do get unlucky and get a sick basil plant, check the pH or nutrient level and try to correct those issues. Hopefully your plant will come back to life.

Conclusion – Basil Plant Leaves Turning Yellow In Aquaponics

This article has provided you with a wealth of information on how to diagnose and treat various causes of basil plant leaves turning yellow in aquaponics. Put this information to good use and you will have a very happy and productive basil plant in your aquaponics system.

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