Letting the grass grow is more than just a proverb. Many gardeners experience improved appearances in their lawns if they allow the grass to complete its normal seed production process at least once a season. The grass will grow long and develop seeds, once cut, the new seeds will reseed the lawn, creating a lush, full look. Resisting the urge to mow when a lawn starts to look long or uneven is perhaps the hardest part of this natural process.
Maintain your lawn in good condition during the season by watering, mowing and fertilizing on a regular schedule. When you would like to reseed your yard begin to taper back the frequency of watering and adjust your mower so that it mows the lawn higher and higher each time.
Stop mowing your lawn once it reaches the highest setting. Keep foot traffic off your lawn to keep the grasses from matting down.
Water your lawn for a longer time with a longer interval between watering, this encourages deeper root growth. Once you see seeds on your grass shoots, allow the seeds to mature and dry out.
Remove the bag from your lawn mower and mow the dry grass and seeds allowing the seeds to fall into the lawn.
Fertilize the lawn with a seed-starting fertilizer. Some lawns will go dormant after seeding and the fertilizer will remain in the soil to give the spring lawn a boost when the new seed comes in.