How Long Does It Take to Reseed Grass?

Existing Turf Improvement

• One of the fastest reseeding projects is overseeding your existing turf. Your yard may simply have a thinning appearance with bare soil being exposed to potential weeds. Depending on your yard size, reseeding could only take one weekend. Choose a sunny, autumn day to mow your grass. Cut it to the lowest height your species can withstand, such as 1 1/2 inches. Your freshly mowed yard allows seeds to fall between the blades for rapid germination. Carefully spread the new grass seed into the turf using a spreader. With a thorough watering, your reseeded yard should have a more lush appearance in approximately one month, depending on the grass species.

Patchy Spots

• If your yard has a few bare, patchy areas, reseeding can only take one day to complete. You should till the soil in the bare area and add some organic matter -- this soil addition improves the ground's texture and nutrient levels. Hand-spread grass seed into the tilled area and water it. Using straw as a mulch, lightly cover the seeds to protect them from moisture loss and wind movement. Although your bare areas will not be filled in for at least another month, you can continue to mow around the areas until all the grass is growing at the same height.

Complete Turf Removal

• Your yard may be infested with so many weeds that the turf needs a complete removal for reseeding. This is a long-term project that can take at least one month to several months, depending on the yard's square footage. Initially, the turf needs to be killed and raked away. Instead of using herbicides, use black plastic covering your entire yard for about three weeks to cause widespread grass dieback. After removing the old grass with a rake, you should amend your soil with organic matter and starter fertilizer, based on your new grass seed species' needs. The yard must be leveled with a rake before you spread the new seed. Depending on the grass type, it can take as long as four weeks before your seeds germinate into strong seedlings -- consistent watering is key during this development period.

Germination Influences

• Reseeding projects are greatly influenced by surrounding soil temperatures -- most seeds need temperatures of at least 50 degrees Fahrenheit to start growing. Only reseed during the spring and fall for the best results. Prune any overhanging tree limbs above the reseeding area to improve sunlight exposure. Proper watering and sunlight are crucial for rapid grass germination.