Sprinkle the seeds lightly over the surface of the soil. Separate any seeds that are lying on top of each other.
Cover the seeds with a fine layer of soil, about the same height as the seed. Water the seeds, so they are moist and not wet. Depending on your soil, you may need to water the seeds daily or every few days in order to keep them moist.
Place the seed trays in an environment that possesses high moisture and high humidity. To increase the moisture, enclose your trays in a plastic tent, with holes poked through. Catnip seeds typically take one to four weeks to germinate, depending on your soil conditions.