Why Are My Basil Leaves Turning Brown?: Common Reasons

If you have ever bought a bunch of fresh basil leaves and found them turned brown in the fridge, it might have been disheartening to see all that hard-earned money go to waste. Basil leaves are typically green in color, but they turn brown over time. This article will answer the question, ‘why are my basil leaves turning brown?’

Why Are My Basil Leaves Turning Brown

Why Are My Basil Leaves Turning Brown

Browning basil leaves are caused by one of several reasons or a combination thereof, so not all cases are cause for alarm. Here are nine reasons why basil leaves turn brown and what you can do about them:


Basil is drought-tolerant, but it still needs water every few days. Overwatering can result in wilted basil leaves and a bad taste. Be sure to pay attention to the soil you choose for your plants, as it is often too dry. If you water your basil plants with a hose, do not leave let it gush on it for more than a few seconds.

Aim to water your plants in the morning and again when they are wilting. It is also critical to let the soil dry out between the waterings. If you notice that your basil leaves have turned dark green, they are not getting enough water but are still getting plenty of sun exposure.

Inadequate light

Basil is a leafy plant, and if you do not provide it with plenty of light, it can turn brown. Therefore, you can keep your basil plants well away from any direct sunlight or introduce some leafy green shade trees or palms to block out some sunlight. If you are growing basil indoors or in a container garden, make sure your container receives full sunlight for at least 12 hours a day. You may want to place your container in an area that gets indirect sunlight to save energy.


Why Are My Basil Leaves Turning Brown

Just like most other plants, basil also thrives best at moderate temperatures. It grows well in temperatures below 80 degrees. Make sure you take good care of the plant, especially in terms of temperature – do not set the AC too low or the heater too high. If you keep your basil leaves in a cold place, they might absorb more moisture from the air and turn brown faster; conversely, if you place them in a scorching environment next to a lit fireplace or in direct sunlight, they will brown too.

Too much fertilizer

Some people could be giving too much fertilizer to their basil. The result is weak or yellowing leaves. If you feel that your plant needs more fertilizer, but are unsure how much, then use the three-year rule of applying one-third of the recommended amount at each feeding.

Further, basil is a heavy feeder in terms of calcium and magnesium; it needs these nutrients to stay fresh and healthy, but if it does not get enough of it from its growing environment or supplements, it will turn yellow and begin to grow stunted as a result.

Improper soil pH

Basil plants are mildly acidic, which means they need less than 4.5 pH of water monthly. If it is too high or too low, your basil leaves will turn brown, and the plant will become weak.

Attack by diseases

The leave of your basil plant can turn brown due to attack by diseases such as:

Leaf Stem Rot: This disease is caused by two different fungi, Fusarium and Verticillium. The fungus attacks the pith of the leaf stems, causing them to soften and collapse around midseason. It is a common problem in hot weather or overly wet conditions. To prevent this condition, avoid overhead watering as much as possible to help reduce plant stress and keep leaves dry until they can be spread out evenly to dry in the sun.

Rust: This disease is caused by a fungus that attacks many types of plants, including basil. It causes yellow or orange spots with light green borders. The spots later turn into pustules that develop orange spores inside. If you notice rust on your basil plants, the best way to prevent this disease is to rotate where the plant sits in your garden so that it does not always grow in the same place.

Sunscald: Another common problem is caused by leaf exposure to direct sunlight late in the day, which causes sunburn and sometimes drying. When the sunburn occurs, it causes the leaf to become brown. That is a common problem in hot weather and can occur with large basil plants in full sun in the garden or with smaller pots of basil next to a window. To prevent this condition, move your basil plants indoors in many areas during some months.

Fusarium Wilt: This disease attacks tall or upright basil plants grown outdoors or kept indoors during winter. It happens when soil becomes too dry and can lead to root rot. To prevent this disease, make sure to mulch your outdoor plants with at least two inches of aged manure or compost every fall before you plant new seedlings outdoors.

Why Are My Basil Leaves Turning Brown: Conclusion

There are many reasons why basil leaves turn brown, and not all of them are cause for concern. Just remember to water it regularly (but not too much), keep a check on any insects that might be present, keep it away from direct sunlight, fertilize your plant well, and soon have a flourishing basil plant growing in your kitchen.

Related Article: How to Revive a Basil Plant