Q.Harvesting Spearmint
What is the correct way to harvest spearmint? I have seen references to sprigs, stems, etc. How do I tell the difference of each, and what is best way to harvest (i. e. pluck leaves, cut sprigs or stems) and how far down? I get plants (in large pot) to grow nicely, only to have the plant slowly die once I start harvesting. I live in south Florida where we have hot to warm weather usually 12 months a year.

Certified GKH Gardening Expert
Sprigs and stems are essentially the same thing. Typically you would harvest it like you were giving the plant a haircut. Simply cut off what you think you need.
It sounds like the plant may be dying after harvest due to disease getting in the open wounds. Trim only with very clean scissors and shears. You can wipe them off with rubbing alcohol even to kill anything that may be on the blade that could hurt the plant. Then, after you harvest, provide a little more water to the plant so that it is less stressed and can fight off disease better.