Basil is revered worldwide owing to its culinary and medicinal uses and its sacred status.
The aromatic herb is reasonably easy to grow and doesn’t require special maintenance. However, it has its fair share of problems, and the leaves turning brown is one of them.
The most common causes are insufficient exposure to sunlight, watering issues, bacterial infections, and pests, among others.
Let’s explore how to nip this issue in the bud before it spreads to the entire plant.
Why Are My Basil Leaves Turning Brown?
Common reasons why your basil leaves are turning brown include:
1. Not Enough Sunlight
Basil plants love sunlight and require 4-5 hours of sun exposure daily. If you’re not giving your plant enough sunlight, it can cause its leaves to brown and eventually die.
How To Fix Sunlight Issues?
If you’re growing basil indoors, ensure the plants get at least six hours of indirect and four hours of direct sunlight daily. However, you shouldn’t leave them in the sun for too long. If there isn’t enough sunlight, ensure you keep them under artificial lighting.
Young basil plants should receive less sunlight, and as they grow, you can increase the duration.
Common basil pests include aphids, slugs, spider mites, thrips, and Japanese beetles. Browning of leaves and brown/black spots are signs of their presence.
Other pests can cause symptoms such as small holes on leaves or damaged foliage— you shouldn’t be wary only about the browning.
How To Fix?
The best way to manage pest infestation is to treat them with home remedies. These natural remedies include:
- Mix small amounts of dish soap and plenty of water in a spray bottle and spray it on the leaves.
- Avoid placing the basil in direct sunlight during treatment.
- Manually remove the pests from your plant.
- As a last resort, you can spray insecticidal soap on the leaves.
Another reason for basil leaves turning brown is not watering the plant enough to meet its requirements. Whether your basil is placed in a shaded or warm area, you must ensure it gets enough water.
If not, the leaves can become brown, curl, or shrink.
One of the most common signs of underwatering in basil is bitter-tasting leaves.
How To Fix?
Although it’s good to have a watering schedule for your basil, you still need to check your plant every day. If the top two-inch patch of the soil feels dry, you should water the plant.
Basil plants usually like to stay moist— you should water deeply once a week.
Plants that are kept by the windowsill or grown outdoors will need more water because of the loss of moisture due to sunlight.
4. Bacterial And Fungal Infections
Like other plants, basils are susceptible to bacterial infections, which can cause the browning of leaves.
Colletotrichum is an example of bacteria that causes basil leaves to brown. If you notice dark color around the brown leaves, it can also be from the fungi Septoria.
How To Fix?
Before you conclude that bacteria are affecting your plant, you need to strike off other possibilities. If bacterial infection is the only plausible reason, use the following remedies:
- Mix baking soda, small amounts of dish soap, and plenty of water in a spray bottle to spray the leaves.
- If the leaves look damaged beyond repair, you can prune them.
- Use chemical or organic fungicides according to the labeled instructions.
- Avoid watering the leaves in the evening to reduce the dampness that promotes fungal growth.
You may have unknowingly put your plant through stress with replanting, causing the leaves to turn brown. Sudden temperature changes can also stress the plant.
How To Fix?
Once you’ve replanted, you should allow your basil to adapt to its new environment by keeping everything minimal.
Protect the sensitive plant from cold weather by moving it indoors. Basil does well in warmer temperatures between 50°F–80°F.
6. Too Much Watering
Basil plants love moisture— however, overwatering can cause more harm than good. The plants require a well-drained soil that’s moist and not clogged with water.
A common mistake gardeners make is planting basil in a container without drainage holes.
How To Fix?
Apart from leaf browning, overwatering can cause root rot and a dozen other problems. The leaves can first turn yellow before turning brown, so watch out for this sign.
You can redeem the plant by replanting it in another soil. Avoid watering your basil when the top inch of the soil feels wet. Also, give your plant enough sunlight to evaporate the moisture.
Apart from its attractive look, basil is packed with several health benefits. As a caring gardener, it can be pretty disheartening to see its leaves turning brown.
However, taking action immediately is essential, or your plant can die. The above guide should help you rescue your plant.
I have found gardening to be my calling since being restricted to my apartment. I love studying rare species of plants and giving them a mention on my blog. I also love growing organic vegetables in my backyard.