Lemongrass can die if it is not getting enough water, lacks nitrogen or develops rust. Lemongrass will also go dormant in cool areas over winter and may look like it is dying. Water your lemongrass well, feed it with a nitrogen fertilizer and cut off any areas affected by rust to save your plant from dying. New stalks will grow in the spring once the weather warms up.
Top reasons why lemongrass is dying
Lemongrass needs lots of water
Lemongrass comes from a sub-tropical area so loves to be watered regularly. Lemongrass leaves will start to turn brown and eventually die off on the outside if it is not getting enough water. Lemongrass left to dry out completely can die quickly so act fast to save your plant.
Solution: Improve the soil with organic matter like compost and worm castings before planting. Surround your lemongrass with mulch like sugar cane, straw or hay to keep the moisture in the soil for longer.
Lemongrass needs to be fed regularly with nitrogen
Lemongrass can die off quickly if it is not getting enough nitrogen from the soil. Leafy plants like lemongrass need regular access to nitrogen to continue to grow healthy leaves which will photosynthesize to form food for the plant.
Solution: Give your lemongrass an extra boost of nitrogen using a liquid fertilizer like fish emulsion. For longer lasting nutrients place a handful of chicken manure pellets around the base to give the plant extra nitrogen over 3 months.
Lemongrass will die if rust takes over
Rust is a fungus that can live on the leaves of the lemongrass. They will turn the leaves yellow and then brown and form dark brown spots underneath the leaves. Rust can eventually kill off your plant. The rust is caused when water sits on the leaves and the fungus grows in these water droplets.
Prevent rust problems on lemongrass by only watering in the morning at the base of the plant rather than on the leaves. This will avoid water sitting on the leaves for a long time allowing rust to grow.
Trim the leaves and stems back removing the areas with rust. Remove all affected areas and put them in the bin. Lemongrass will grow back over time. Doing this before the rust takes over can avoid your lemongrass dying altogether.
Mulching around the base of the plant will also help to prevent soil particles from being splashed onto your lemongrass leaves and carrying the fungus spores and prevent rust.
Poor quality soil can cause your lemongrass to die fast
Plant lemongrass into the best quality potting soil for the best results. Choose free draining potting soil that is a premium mix or one that is made to grow vegetables. This will be high in nutrients will drain freely and provide slow release fertilizer.
When planting lemongrass in your garden improve the soil first. I always like to mix a gentle fertilizer and soil conditioner like aged cow manure with some compost and work this into the soil to give all of my plants an extra nutrient boost to start.
Water the lemongrass in with seaweed solution to improve soil microbe levels and settle the roots into the soil.
Winter leaf die back is normal for lemongrass
Lemongrass grown in cooler areas will die back when the weather cools down or when frosts occur. The root bases will stay healthy and protected under the soil but the top leaves can brown and die back when the weather gets cold.
Keep the brown leaves on the plant and do not trim them off until the weather warms up in spring. When the risk of frost has gone, trim back old leaves and make space for new ones to sprout. Leaving the old, dead leaves on the plant in the winter will protect it from further frost damage.
If you are growing lemongrass in a pot it can be moved into a sheltered area protected from the frosts over winter. Move it back out into a sunny area when the sunny days return in spring and your lemongrass will grow back well.
Trim old dead leaves to refresh lemongrass
Trim off any old brown leaves from your lemongrass plant when the weather warms up in spring. This will encourage your lemongrass to sprout new leaves and stems to replace the old ones. Wait until the weather has warmed up and the risk of frost is gone and your lemongrass will spring to life.
How to save dying lemongrass
Save dying lemongrass by watering with a mix of liquid nitrogen fertilizer and seaweed solution. Cover the root zone with straw mulch and make sure the soil is kept moist. If the weather is cool it is likely that your plant has just gone dormant for the winter and will grow back with new shoots in spring.
Do not give up on your lemongrass too early by digging it out. Unless the whole plant including all of the stems are brown and crispy, there is a chance it can grow back.
How to water lemongrass
Lemongrass should be watered regularly over the summer months. Check the soil moisture 1-2 inches below the surface and water the plant deeply. Watering lemongrass 2-3 times per week deeply is better than a shallow water every day. This will help to encourage the roots to grow deep to access moisture and stabilize the plant.
Keep the water off of the leaves to avoid encouraging rust from developing and surround the base of the plant with mulch to stop soil from splashing onto the leaves.
How to tell if your lemongrass is dead
Dead lemongrass will look completely brown all over including all of the stems and leaves. The central root ball and deep stems will look dry and brown and there will be no white left in the stems. Cut a piece of lemongrass stem off to check to see if there is still a white center. If there is your lemongrass might still spring back to life if it is well cared for.
Lemongrass will go very brown and dry if it has died. If you see any white stems, leave the plant in the ground, surround it with mulch and see if it grows back in the spring. If it still doesn’t grow then you may have to try a new plant.
Why lemongrass will wilt
Lemongrass will wilt for two main reasons, it is not being watered enough or the weather is too cold. If the soil is dry 2 inches below the surface your lemongrass might need a good watering in to stop it from wilting. Water it well in the morning and it should stand up straight the next day.
Lemongrass will also wilt if the weather is cold. This is a protective measure and the leaves will slow their growth and may turn brown. Keep the leaves on the plant over winter to protect the stems and trim any dead leaves back in spring.
Your plant should grow back well when the weather warms in the next spring.
Why is my lemongrass dying – Summary
Lots of people can mistake a dormant lemongrass plant with one that is dead. Give your lemongrass a chance to grow back and don’t remove it until you are absolutely sure there is nothing else you can try. Water, nitrogen and mulch can solve a lot of plant problems including dying lemongrass.
Happy gardening.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.