The failure of your grass seed to sprout could be due to several environmental factors. These often include inconsistencies in watering (applying too much or too little), adverse weather conditions, the presence of weed control chemicals, or underlying problems with poor soil quality.

Overseeding is the practice of spreading grass seed across your current lawn to naturally thicken the turf. Lawns inevitably become weak and thin due to common seasonal pressures, including pests, drought, and extreme weather. This technique offers a cost-effective and speedy way to rejuvenate your grass, bringing back its lush, dense color without the labor and expense of tearing up the old lawn and completely starting over.

Proper preparation is key to successful overseeding: Begin by mowing your lawn short and bagging the clippings. Next, lightly rake the area to loosen the topsoil and remove debris and dead grass, which helps the new seed access the soil.

Applying the Seed:

• For Cool-Season Lawns: We recommend using Scotts® Turf Builder® Thick'R Lawn™. This product is specifically formulated for overseeding, combining seed, fertilizer, and a soil improver in one easy application via a Scotts® Spreader.
• For Warm-Season Lawns (like centipede, zoysia, or bahiagrass): Choose the matching variety of Scotts® Turf Builder® Grass Seed and distribute it over the lawn using a spreader.

Overseeding serves to thicken a thin lawn, whereas reseeding is reserved for situations requiring a complete renovation. When your yard is overrun by weeds and bare patches, starting over is the best approach. The steps for reseeding are exactly the same as putting in a brand new lawn.

While grass seed can technically last for 2 to 3 years when stored in a cool, dry location, its performance diminishes over time. The germination rate (the percentage of seeds that sprout) will decrease, meaning older seed may not yield the lush results of a fresh product. For the best outcome, plan to use fresh seed and plant it within one year of purchase.

To purchase the correct amount of grass seed, you first need to determine the square footage of the area you plan to plant. Once you have this measurement, you can determine the number of bags needed by checking the package for two distinct coverage numbers:

• Overseeding Coverage: This is typically the higher number, indicating how many square feet the seed will cover when spread over an existing, thin lawn.
• New Lawn Coverage: This is usually the lower number, indicating coverage for reseeding (starting from scratch) or planting a completely new lawn.

While it is essential to read all package directions carefully, the overseeding coverage is generally found on the front of Scotts® seed packages, while the new lawn coverage is listed on the back.

The ideal time to plant depends entirely on your grass type:

Cool-Season Grasses (Fescues, Kentucky bluegrass, etc.)

• Early fall is optimal, as the cooler nights (60–80°F) and heavy dew aid root development before winter. The two weeks before or after Labor Day is typically the most successful period.
• Spring planting is also acceptable due to moderate temperatures and rainfall. However, watch out for crabgrass. To protect your new seedlings and boost root growth while preventing crabgrass, apply Scotts® Turf Builder® Triple Action Built for Seeding.

Warm-Season Grasses (Zoysiagrass, Bermudagrass, etc.)

• Plant from late spring (after the last frost) through early summer, when temperatures are consistently warm (75–90°F). We recommend applying Scotts® Turf Builder® Starter® Food for New Grass at this time to boost root development.

Before planting new grass, you must observe a necessary waiting period after using weed control products.

In general:

• Wait at least 4 months after applying a crabgrass preventer.
• Wait at least 1 month after using other weed control products.

Exception: You can disregard these timelines if the weed control product is explicitly designed for use when seeding. Always check the product label for accurate instructions regarding planting intervals.

Watering is vital for germination and initial growth. For the first 2–3 weeks, water frequently enough to keep the top one inch of soil consistently moist, avoiding sogginess. Mist the seedlings daily or as needed to maintain this moisture level. Once the new grass is established and has been mowed at least once, transition to watering only twice a week, applying roughly 1/2 inch of water during each session.

When to mow depends on how the grass seed was applied:

• Reseeding or New Lawn: Do not mow until the new seedlings reach the target mowing height (typically 3 to 4 inches tall). When you do mow, ensure your blade is sharp, only cut the grass when it is dry, and never remove more than one-third of the grass blade height in a single session.
• Overseeding: If you applied seed over an existing lawn, you may continue to mow as needed, but limit the frequency to minimize foot and equipment traffic on the delicate new seedlings.

To avoid damaging new grass, you will generally want to wait until the turf has been mowed 3–4 times before applying any standard crabgrass preventer or weed control product. The only exception is if the product label specifically allows for use during seeding.

• For Cool-Season Crabgrass Control While Planting: Use Scotts® Turf Builder® Triple Action Built for Seeding. This product safely prevents crabgrass and promotes strong root growth for new plants. (Important: Do not use this on warm-season grasses; confirm compatibility on the product label.)

Always read the specific label instructions for the product you purchase.