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Basil Stem Turning Brown or Black: Here’s Why and What to Do

I once discovered that the base of my basil bush’s stem was turning brown and woody, sparking concern about disease. Digging deeper, I found the stem under the soil was not as brown. Some new leaves looked misshapen and wrinkled, but their color was normal. After researching and consulting a plant researcher, I found the answer.

The hardening and browning at the base of the stem is evidence of healthy growth. This part must be the most robust as it takes on the most force. As it grows rapidly, this hardening prevents it from falling or breaking. This is common in many herbs, not just basil, and isn’t a disease, so do not need to take any action.

Also my plant researcher friend said about the new leaf deformation that this is likely temporary dehydration.

As temperatures are rising and the pot might be a bit small (though it looks just right), the roots may not be supplying enough water for the leaves. More frequent pruning to reduce leaves or transfering to a larger pot would be better.

But what if your basil stem turns black? This may be fatal to your basil, so it’s essential to uncover the causes and take action. Let’s explore what might cause your basil to turn black.

Why Do Basil Stems Turn Black?

Fusarium Wilt (Seedling Blight) 

The browning or blackening of basil stems is often attributed to a disease known as Fusarium wilt, or seedling blight. It is caused by mold and can occur in not only basil but almost all plants.

When a plant is affected by Fusarium wilt, the stems rot, and the plant eventually dies. If you notice the stems turning brown or black, it’s time to suspect this disease.

Can You Eat the Affected Stems? 

The topic of whether or not you can eat basil affected by Fusarium wilt is not widely discussed. However, since the disease is caused by mold, it’s better to avoid eating it.

If your plant becomes infected, it’s advisable to remove the roots and start with a fresh new soil before the disease spreads widely. You need to disinfect the pot and clean it with bleaching water.

Tips for Cultivating Basils Without Turning Them Brown or Black

Wondering how to grow your plants without them turning brown or black? If they contract wilt disease, you must take immediate action.

Here are some handy tips that helped me to prevent wilt disease of my basil. 

Be Careful Not to Overwater 

Basils love moisture, so be mindful of the soil’s humidity. Overwatering can lead to wilt disease. Work on improving drainage, especially during the rainy season.

Too much watering or poor drainage can cause oxygen deficiency, leading to root rot. Make sure to water only when the soil starts to dry and consciously choose soil with good drainage.

Choose a Slightly Bigger Container

By using a slightly larger container, you can improve the drainage. The material of the basil pot affects how well it drains.

Remember that the proper pot size varies depending on the plant you’re growing, so adjust the container size accordingly.

Key Takeaways

  • It is natural when the basil stem turns brown as it ages.
  • The cause of basil stems turning brown or black can also be caused by wilt disease.
  • If wilt disease occurs, remove the stem and soil to prevent it from spreading.
  • To prevent wilt disease, don’t water too frequently and use a larger container.

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