About a week ago I decided to propagate a healthy stalk of mint that I had bought from the grocery store. The roots appear to be healthy and full, but two of the leaves appear to be abnormal. One of them is brown, and the other has a light green/black/brown spot near the center of the leaf.
What's going on?
Is your plant being kept indoors? Mint likes plenty of sunshine and humidity. The indoors may not provide enough of either.
That is perfectly normal when you are propagating plants. Plants from the grocery are in very low light, and other conditions that stress them. When you put them in warmer conditions to propagate them, they start to regenerate and produce roots. The plants often loose some leaves (there is too much leaf surface for the plant to maintain a proper water balance). But mint is very resilient. A week is no time at all. Mint is a bit easier than other herbs indoors. However like all herbs mint will need lots of light. And keep it out of central heating air currents.
