Not just cats will appreciate you planting catnip seeds. Catnip has a history of use as a beverage and a medicine. Before European trade with China began bringing large quantities tea to Europe, catnip tea was a popular beverage. When growing the plant for this purpose, mature leaves should be collected while they are still fresh and dried in the shade for several days. One teaspoon of the dried herb is then added to each cup of boiling water and allowed to steep. What cats are fond of is a component of the mint's oil called nepetalactone.