Answer: I'm not sure I understand what it is you plan to do. You can start grass seed in trays or flats and then transplant them into an existing lawn, but it would be far easier to simply sow the seed where you want the grass to grow. If you already have established turf with bare spots in it, you can rough up the soil, sow the grass seed, cover over it with peat moss to help hold in moisture, and then keep it well watered until the grass seed germinates. If you've purchased the grass patch that looks like paper fibers with grass seed and fertilizer already in it, you can place them in bare spots in the lawn and water them down well. They will sprout in a week or so.
Hope this answers your question!
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