Preserving your own grass seed is not only easy, it is also very economical. Ornamental grasses of many varieties will produce viable seeds that can be collected and planted the following spring. With a few tips in hand, you can preserve the seeds of your own grasses as well as maybe from a friends' yard.
Harvest the seed heads from the grass around midday when any traces of the morning dew have had a chance to dry up. Typically, grass seeds are harvested in the fall when the seed heads are plump and ripe, but sometimes they can be ready in late summer. Cut the stem about 6 inches below the seed head and lay it in a basket.
Bundle the stems together with either the string or rubber band and place them upside-down in the brown paper bag. Give them a vigorous shaking to remove them from the stem. If you find that they plant is still too green, just bundle the paper bag around the stems and hang it up to dry for a few more weeks.
Pour the seeds out of the paper bag and into an envelope. If you are collecting a large amount of seeds, you might find a manila envelope a better-sized container. Seal the envelope and then tape it shut to make sure none of the seeds escapes.
Label the envelope with the date, the name of the seeds and any distinguishing characteristics you might think are necessary. Store the envelope in a dry, cool place away from any threat of rodents and away from sunlight.