Pour water into the top of the rosemary pot using a small watering can until the soil is saturated. Wait five minutes, then dump any excess water out of the tray in the bottom.
Test the soil periodically by pressing your finger into it. When the top 2 inches feel dry, it is time to water again. This takes about one week in the summer months but will vary depending on the climate.
Water less frequently in the winter when the plant is dormant. Let the soil dry out almost completely, then water the plant. This can take two or three weeks between waterings.