Purchase a plastic or metal tray that is 2-inches deep. The length and width of the tray don't matter; get one that fits in the area you wish to decorate. You may use recycled baking pans, plastic trays or shallow planters.
Punch holes on the bottom of the tray using a hammer and nail. Space the holes in a regular pattern, 3-inches apart.
Fill the tray with a 1 1/2-inch layer of fresh potting soil. Do not reuse soil from other planters as they will have fewer nutrients and may harbor weed seeds or diseased organisms.
Sprinkle a thick layer of grass seed over the soil. Use a fast-growing variety of seed, like wheatgrass, fescue or oatgrass.
Sprinkle the soil and seeds with water to dampen them. Cover the seeds with a layer of dampened coffee filters. Place the tray in a warm spot until the seeds begin to sprout. Be sure to keep the coffee filters damp.
Remove the coffee filters when the grass has started to sprout. Place the grass in a sunny window or under a grow lamp. Keep the soil moist, but not wet by misting it daily.