Can you let me know at what temperature I should bring my lemon balm plant inside so that it won’t spoil? I don’t know if it can take frost or not.
Lemon balm (Melissa officinalisis) is hardy from zone 4 to 9. It is a perennial herb that grows best in cool weather.
In the fall you can cut back the plants leaving just 2 inches of stem. The plant may freeze back to the ground in winter but will re-grow from underground roots in spring. If you grow lemon balm in a container choose one that’s 6 to 8 inches deep and wide. Over-winter the plant in a protected area such as an unheated garage or sun room, if you wish to continue harvesting the leaves. If this plant is left outdoors the tips of the leaves will get spoiled by frost, so bring inside before that happens. To determine when you should bring in keep an eye on the local weather forecast. If frost is likely then bring your plant inside immediately.
Remember that any frost date will be based on past winters and an average will be taken. Predicting what actually will happen is next to impossible.