Starting From Seed If you live in zones 3 to 9, then you can sow catnip seeds outdoors between spring and late summer. Otherwise, starting them indoors is the better option.

How many seeds you plant should depend on your preference as well as the container sizes. If this is your first time starting seeds indoors, try 20 seeds or less.

Paging through seed catalogs and ogling rare varieties might become your new favorite pastime. Ahead, we spoke to gardening experts about how and when to start seeds indoors.

Give your garden a head start by starting your seeds indoors. When your last frost date rolls around, you'll have seedlings ready for planting in the ground.