- 1). Wait until temperatures are warm enough in the spring that there is no risk of frost. Grass may grow up to this point, and you can mow it as you like, but it will need ample sunlight and energy to produce seed.
- 2). Stop mowing once temperatures have reached an average of 65 to 75 degrees. Grasses that set seed---most of the cool grasses and a few of the warm grasses---do so as a natural part of the growth cycle. All you have to do is let them reach that phase of maturity.
- 3). Allow the grasses to flower (signs of flowering vary according to the particular species you have in the yard), and then wait about three weeks for seeds to form.
- 4). Harvest by hand or with a mower that has a mulching bag attached. Hand harvesting will get seeds and leave out any grass cuttings, but can take a lot of time. The lawn mower setup is best if you plan to utilize the seed relatively quickly. Otherwise, the grass clippings will begin to decompose and the seeds mixed in with clippings will germinate prematurely.
- 5). Store seeds free of grass clippings in a cool, dry place until needed. They'll last up to a year or so depending on the variety.
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