Lemon Balm leaves turning yellow and brown - Ask Extension
Hello, I planted a new lemon balm start a few weeks ago in a container and it has leaves that are turning yellow and brown. I tried looking online for...
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Lemon Balm leaves turning yellow and brown #789499
Asked May 05, 2022, 5:53 PM EDT
Hello, I planted a new lemon balm start a few weeks ago in a container and it has leaves that are turning yellow and brown. I tried looking online for answers and a common yellowing reasons mentioned root rot or not getting enough water. I checked the roots and they look healthy and white and the container is outside and has been getting all the rain we have been having recently in the Portland area. Do you have any tips on how to treat the lemon balm plant? Thanks!
Washington County Oregon
Expert Response
Thank you for your question, Nisha. Here is a description of this species: https://hort.extension.wisc.edu/articles/lemon-balm-melissa-officinalis/ Yellowing is typically caused by inadequate nutrients (fertilizer), or because the plant lacks adequate drainage. Does your plant's container have a drain hole? How often have you fertilized it? Thank you for more information!
Hello!
Thanks for the reply! The container does have drainage holes along the length of the container on both sides. I put some all purpose fertilizer in the soil when I opened up a space to put the start.
Thanks,
Nisha
Well, you may have added too much fertilizer, and the roots are burned. I'm afraid you'll need to be patient to see if it survives. Good luck!
Oh bummer. How should fertilizer have been applied instead? It was probably 1-2tsp of the powdered 4-6-2 I mixed into the soil before adding the plant.
"Follow label instructions" is the best advice we can give.
I did some more research on your plant, Nisha, and its leaves are supposed to be yellow (the label says "All Gold Lemon Balm"). But, as you indicate, the leaves are browning. I found the following article, which indicates that "‘All Gold’ is a selection with yellow leaves that develops the best color in partial shade." https://hort.extension.wisc.edu/articles/lemon-balm-melissa-officinalis/
So, your plant may be getting too much sun. The other thing that stands out is your use of a fertilizer with a 4-6-2 nutrient ratio, that was mixed into the soil, rather than dissolved in water first. This is where the plant's distress may have arisen. The "4-6-2" means that, by weight, the fertilizer contained 4% of nitrogen, 6% of phosphorus, and 2% of potassium. Nitrogen is necessary for photosynthesis; phosphorus is necessary for a healthy root system; and potassium promotes healthy flowers and seeds. In the future, I suggest that you use a balanced fertilizer such as 10-10-10, and, if it is a soluble form, be sure to dilute it exactly as the label indicates before applying to the plant. If, on the other hand, it is time-release, such as pellets, apply per label directions and all of the nutrients won't be available to the plant at once. Over time, the water you apply will dissolve a little bit into the soil, and the chances of your overapplying will be diminished. I hope this helps!
So, your plant may be getting too much sun. The other thing that stands out is your use of a fertilizer with a 4-6-2 nutrient ratio, that was mixed into the soil, rather than dissolved in water first. This is where the plant's distress may have arisen. The "4-6-2" means that, by weight, the fertilizer contained 4% of nitrogen, 6% of phosphorus, and 2% of potassium. Nitrogen is necessary for photosynthesis; phosphorus is necessary for a healthy root system; and potassium promotes healthy flowers and seeds. In the future, I suggest that you use a balanced fertilizer such as 10-10-10, and, if it is a soluble form, be sure to dilute it exactly as the label indicates before applying to the plant. If, on the other hand, it is time-release, such as pellets, apply per label directions and all of the nutrients won't be available to the plant at once. Over time, the water you apply will dissolve a little bit into the soil, and the chances of your overapplying will be diminished. I hope this helps!
