Pick the catnip by cutting the stalks a few inches above the ground with a pair of gardening shears.
Separate the plants into small bunches of about six plants per group.
String each bunch together by wrapping a rubber band or piece of string around the lower portion of the stalks.
Hang each bunch upside down in a well-ventilated area, with a room temperature between 70 and 90 degrees Fahrenheit.
Remove the leaves once they become crispy and put them in an airtight container. Store them in a cool, dark area and use as needed.
Preheat the oven to about 100 degrees Fahrenheit.
Place the catnip in a single layer on a cookie sheet and set it in the oven.
Stir them around on the sheet with a spatula in 30 minutes and then stir them again every 30 minutes for three to six hours or until they are crispy from drying.
Allow them to cool and then store them in a cool, dark area in an airtight container.