1. Dig up. Divide plants in early spring or late fall when they are dormant (resting, not growing). Plants that grow in clumps, such as chives (shown), and those that increase via underground runners, such as mint, make good candidates for division. Dig up an entire plant or slice through the parent plant and take one section.
2. Cut. Divide the plant using a sharp knife or spade. Insert the tool into the middle of the plant and cut it in half. Repeat the process to divide a plant into quarters, eighths, or smaller sections. Each division must have roots and shoots. Some herbs, such as chives and lemongrass, divide easily by gently pulling them apart. For herbs that produce shoots from underground runners, such as mint and catnip, dig up the new plants and treat them as young transplants.
3. Replant. Immediately plant new divisions to prevent their roots from drying out. If you cannot replant them right away, keep the roots moist. Set the plants out of direct sun until you transplant them.