Ah, lemongrass. The fragrant, citrusy herb adds flavor to Southeast Asia, the Caribbean, and beyond dishes.
Lemongrass is easy to grow and care for – that is, until the leaves start turning brown or red. Many gardeners are puzzled when they find that their lemongrass leaves have turned brown or red.
There are several possible explanations for this phenomenon but first, let’s understand the ideal conditions required. Lemongrass is a tropical plant that thrives in warm, humid climates. Lemongrass prefers moist and well-drained soil, and it needs full sun to partial shade to thrive.
Why Is My Lemongrass Turning Red or Brown
Under normal conditions, lemongrass leaves are green. However, there are a few reasons they might turn brown or red.
Under Watering
- Originally from tropical regions, lemongrass requires consistent moisture to prevent the leaves from drying out and turning brown.
- If the plant is not getting enough water, the leaves will start to turn brown at the tips and edges.
Read: Why Is My Lemongrass Leaves Turning Yellow?
Over Watering
- When grown in temperate climates, lemongrass must be watered sparingly to prevent it from becoming stressed.
- The first thing most gardeners do when they notice their lemongrass is water stressed is they tend to overreact by giving the plant too much water.
- However, this can cause more harm than good, leading to water logging.
- If you notice the leaves turning brown or red, this is a sign that the plant is not receiving enough oxygen.
- The roots are suffocating in waterlogged soil, and the leaves are turning red in an attempt to get more oxygen from the air.
- Too much water is preventing proper oxygen exchange. To prevent this, plant lemongrass in well-drained soil and water only when the top inch of soil is dry.
Read How Do You Keep the Lemongrass Plant Healthy?
Lack of Nutrients
- Another reason your lemongrass looks a little lackluster may be a lack of nutrients in the soil.
- Also known as under fertilization, this common problem can cause the leaves of your lemongrass to turn brown or red.
- Plants communicate to us through their leaves. For example, when they’re deficient in a particular nutrient, they will show it by changing color.
- For example, a nitrogen deficiency will cause the leaves to turn yellow, while a phosphorus deficiency will cause them to turn red or purple.
- All these forms of communication are the plant’s way of telling you it needs more nutrients, and if you are not paying enough attention, the leaves will begin to die.
- If you think your lemongrass is not getting enough nutrients, try feeding it with a balanced fertilizer and see if that makes a difference.
Also Read: Why Is My Lemongrass Plant Dying? [11 Reasons & How to Prevent]
Too Much Fertilizer
- Like too much or too little water, too much fertilizer can cause your lemongrass’s leaves to turn red or brown.
- When you fertilize, you give the plant a concentrated dose of nutrients. While this is good for the plant, too much of a good thing can be harmful.
- If you notice the leaves turning red or brown after applying some fertilizer, this is a sign that the plant is getting too much fertilizer.
- To prevent this, ensure only to fertilize your lemongrass every few months and use a balanced fertilizer.
Read How to Care For a Lemongrass Plant
Pests
- Unfortunately, pests and diseases are common culprits for lemongrass leaves turning red or brown.
- If your lemongrass looks a little worse for wear, check the leaves for signs of pests or diseases.
- Common pests that affect lemongrass include:
- Aphids
- Whiteflies
- Mealybugs
- These pests can cause the leaves to turn yellow, brown, or red as they suck out the nutrients from the plant.
- If you notice any pests on your lemongrass, try to remove them by hand or use an organic pesticide.
Check: Why Is My Lemongrass Turning Purple? [Reasons & How to Fix]
Fungal Infections
- As any gardener knows, lemongrass is a delicate plant susceptible to fungal infections.
- Brown or red spots on the leaves are often the first sign of a problem, and if left unchecked, the infection can spread to the stems and roots.
- Fungal infections are caused by various fungi, including:
- Pythium
- Phytophthora
- Rhizoctonia
- These fungi thrive in warm, wet conditions and can quickly kill a lemongrass plant.
- The best way to prevent an infection is to plant lemongrass in well-drained soil and to water it only when the soil is dry.
- If you notice brown or red spots on your lemongrass, remove the affected leaves and dispose of them carefully.
- You may also want to treat the plant with a fungicide to prevent the infection from spreading.
- When choosing a fungicide, select one with preventative and curative properties.
- This is because we are trying to cure the already affected parts while preventing the further spread of the infection.
Read What to Plant With Lemongrass
Frost Attack or Low Temperatures
- Lemongrass enjoys warm weather and does not tolerate frost or low temperatures well.
- The plant leaves will turn brown or red if the temperature drops too low.
- Frost damage is typically more severe on the tips of the leaves, but it can also affect the entire leaf.
- If unchecked, this can affect the entire plant and even kill it.
- Protect your lemongrass plant from frost by mulching it or covering it with a cloth to prevent this from happening.
- The best way to do it in colder regions is to plant it indoors or in a greenhouse where the climate is controlled.
Read: Are Coffee Grounds Good for Lemongrass?
Less Sunlight Exposure
- Lemongrass is a sun-loving plant that needs at least six hours of direct sunlight daily to thrive.
- If the plant does not get enough sunlight, the leaves will begin to turn red or brown.
- This is because the browning results from the plant trying to get more sunlight by producing chlorophyll.
- This, in turn, negatively affects the plant’s general health as it starts to become etiolated. This is where the stem of the plant becomes thin and weak due to the lack of sunlight.
Read How To Grow Lemongrass From Seed Indoors
Rescuing Your Lemongrass
While there is no single way of going about this, it is important to determine the cause of the leaf discoloration to save it.
Increase or Cut On watering
- Changing the watering schedule is the best way to correct red or brown leaves caused by too much or too little water.
- To correct dehydration, water the plant more frequently.
- However, as mentioned earlier, don’t bombard the plant with too much water. Instead, give it time to dry out between waterings lest you create a breeding environment for pests and diseases.
- On the other hand, if you think you have been overwatering your lemongrass, cut back on the watering frequency and allow the soil to dry out more between waterings.
- A good rule of thumb is to water your lemongrass only when the top inch of soil is dry. This is an indication that the plant is ready for more water.
Balance Your Feeding
- The first thing to do is to test your soil’s nitrogen levels before applying fertilizer.
- Once you know how much nitrogen is in the soil, you can add the appropriate fertilizer to achieve balance and stop those pesky leaves from browning.
- However, before you go about your fertilizer application, first, look at the type of fertilizer you’re using. If it’s high in nitrogen, that could be the problem.
- Nitrogen Naturally occurring in the environment, nitrogen is an essential component of all living things- including plants.
- However, too much nitrogen can cause leaves to become brown and stunted. If your fertilizer has a high nitrogen content, try using less next time you fertilize your lemongrass.
- You might also want to add some phosphorus-rich compost to your lemongrass bed. Phosphorus is another important nutrient for plants, but it’s often lacking in soils.
- Adding a bit of compost will help balance the nutrients in your soil and encourage healthy growth.
Read How to grow Lemongrass From Cuttings
Treat Your Soil
- In the case of pests and diseases, it is best to start by treating the soil.
- This will help to get rid of any pests or diseases that might be present in the soil and prevent them from infecting your lemongrass.
- One way to do this is to solarize the soil. This is a process whereby the soil is heated to high temperatures using the sun’s rays.
Create a Favorable Environment
- As we have seen, lemongrass is a sun-loving plant that needs at least six hours of direct sunlight daily.
- If the cause of leaf discoloration is a lack of sunlight, move your lemongrass plant to a sunny spot.
- Lemongrass also prefers warm temperatures, which will not do well in cold climates hence the frost attack.
- If you live in a colder region, it’s best to grow your lemongrass indoors or in a greenhouse where the climate is controlled.
Moreover, you may like some more Gardening articles:
- Are Coffee Grounds Good for Hydrangeas?
- Why are my hanging basket plants dying?
- Homemade fertilizer for areca palm [Caring Tips]
- How to prune areca palm [Complete Guide]
- Polka Dot Plant Turning Yellow [How to Fix]
Takeaway
- Lemongrass is a very versatile plant with a host of benefits. However, like all plants, it is susceptible to pests, diseases, and nutrient deficiencies.
- One common problem that lemongrass plants face is leaf discoloration.
- Several factors can contribute to this problem, including too much or too little water, too much fertilizer, or not enough sunlight.
- If you want your lemongrass plant to survive, it is important to identify the cause of the problem and take corrective action.
- Following the tips above, you can keep your lemongrass plant healthy and prevent leaf discoloration.
I’m Elsa, and I love gardening. I started GardeningElsa.com as a resource for other gardeners, and I offer expert advice on gardening topics such as plants, flowers, herbs, and vegetable gardening. On my website, I share my latest tips and tricks for creating beautiful gardens. When I’m not working on my website, you can find me in my own garden, tending to my plants and flowers. Read more about me.