Place the potting soil in a bucket or bowl. Water the soil thoroughly and allow it soak up the moisture for 20 to 30 minutes. The soil is ready to use when it feels as damp as a wrung-out sponge.
Fill 2-inch diameter seedling pots with the moistened potting soil to within 1/2 inch of the rim.
Sow the two to three catnip seeds on the soil surface in each pot. Cover the seeds with a 1/8-inch layer of moist soil.
Cover the pots with a clear plastic bag to retain moisture during germination. Set the pots in a warm area to germinate, between 70 and 75 degrees Fahrenheit.
Remove the bags and mist the soil surface lightly with water from a spray bottle if the soil surface begins to dry out before germination. The seeds usually take two weeks to germinate. Remove the bags and place the plants in full sunlight once they sprout.