Best lawn ever? Take these easy steps for overseeding during ‘revival time’ this fall

It’s lawn seeding time. Many lawns need to be revived by overseeding after one of the hottest months of July on record, combined with drought conditions. Timing is critical as the window for success is short.

Early September is the ideal time to overseed bluegrass and tall fescue lawns. Warm soils and cooler nights result in quick germination and establishment. Soil preparation, seed selection, fertilization and irrigation are all essential factors that contribute to success.

Prepare the soil by core aeration and/or verticutting.

Verticutting slices grooves in the soil and creates increased exposed area for grass seed to fall on and germinate. Verticutting provides good seed to soil contact and an even distribution for a uniform stand. Core aeration pulls finger-sized plugs from the soil 2 to 3 inches deep.

Start by mowing the grass short (1 to 1.5 inches), then verticutting in one or two directions. Remove any debris from the lawn to improve seed-to-soil contact.

To ensure success, use a good quality seed. Inexpensive mixes contain species such as creeping red fescue, fine leaf fescue, perennial, annual rye and annual bluegrass. These species look good after seeding but will soon fail under stressful conditions.

Read the label on the bag to ensure you are using varieties of bluegrass or tall fescue only. No other grass species will tolerate the weather conditions in the Kansas City area. National brands are often filled with species that are not recommended.

Seed should be applied at half the seeding rate you would use for new lawns. Tall fescue seeding rate is 6 to 8 pounds per 1,000 square feet. The overseeding rate is 3 to 4 pounds per 1,000 square feet. Broadcast the seed over the prepared area. The new lawn rate for bluegrass is 3 to 4 pounds per 1,000 square feet, making the overseeding rate around 2 pounds. Fescue should germinate in about 10 days, while bluegrass may take up to two weeks.

Water in the new seeds and keep the seedbed consistently moist to ensure rapid germination. The usual deeper and less frequent lawn watering schedules are thrown out the window during this establishment period. Instead, the upper layer of soil must be always kept moist with frequent, light irrigation during the establishment of the new seedlings for an even stand of grass. Progress to deeper, more infrequent watering as the seedlings become established.

After seeding apply a starter type lawn fertilizer, which is higher in phosphorus. This boost of nutrients speeds up newly seeded grass establishment, plus existing grass benefits from this application. September fertilization is usually higher in nitrogen, but a starter fertilizer has more phosphorus and aids in root development.

About four weeks after germination, apply a high nitrogen fertilizer such as 27-3-3 or 30-0-0. Repeat this application in mid-November, sending the grass into winter with energy to grow strong once spring arrives.

Lawns surviving the summer and in good condition will not need overseeding. New seed is only needed in lawns requiring a denser stand. Thin lawns with an even stand should recover with good fall fertilization. The greatest success is achieved by seeding on or before Sept. 20 and following all the steps.

Dennis Patton is a horticulture agent with Kansas State University Research and Extension. Have a question for him or other university extension experts? Email them to garden.help@jocogov.org.

This story was originally published September 2, 2022 at 5:00 AM.