I have a kind of perennial evergreen grass that I would like to spread around the yard. How can I save seeds from the plants efficiently ?
I think it's a worthwhile experiment, but there are a few issues with trying to collect seed from your lawn.
- As mentioned in xpda's answer, stop mowing, let the grass grow tall and make seed. Collect them when they're fully dry. Depending on the type of grass you have, it may get tall before it sets seed. Some types actually form seed while they're still fairly low.
- To collect, I would probably walk around with a big paper bag and clip the seed heads (tops of the grass) into the bag. When it's all collected, close up the bag, shake well to separate the seed, and pour it through a screen to separate the debris. Store in a cool, dark, dry place until you're ready to plant it.
- While your desirable grass is going to seed, weeds may have a chance to go to seed. If your lawn is not a pure stand of the desirable grass, the seed you collect may be contaminated with weed seed.
- Depending on the type of grass you have, and the types of grasses that are growing nearby, you run the risk of cross pollination. If cross pollination occurs, the seed you collect will not be a pure strain of the desirable grass. (It could be "better" or "worse" depending on what traits come in via random cross pollination with nearby weeds.)
Some types of perennial grass will spread vegetatively (not via seed). If you have this type, you may be able to take plugs from your existing lawn instead of collecting seed. As long as your lawn is a pure stand and you're not taking weeds up with the plugs, this will ensure that you're propagating a true genetic copy instead of risking cross-pollination.
It's probably easier to buy it than get the seeds from the grass. To harvest the grass seed you need to stop mowing it and let it "go to seed", or let seeds form when the grass gets tall. After they've dried out and turned brown (depending on the grass), you can shake the tops of the grass stalks and the seeds will fall off.
I pick grass seeds by hand some grasses produce big seed spikes that are easy to harvest from however the grass pennisetum cladestinum produces seed in the turf in clusters where the seeds are covered by leaf like bracts whitch can be found near the flowers whitch are easily visible due to their yellow tipped bluish white anthers