Overseeding Your Cool-Season Lawn
START WITH A GOOD QUALITY GRASS SEED
For best results, overseed cool-season lawns during the cooler months in the spring and fall. Choose a good quality grass seed like Gard’n-Wise Premium Fescue Blend, because the quality of the seed determines the quality of your lawn. Premium Blend has a high germination percent and very little, to 0%, weed seed and other fillers. It has a pleasing dark green color and is drought, wear and shade tolerant. The fescues in Kansas Premium have been tested in Wichita and other Kansas towns and are the best types for this area where heat and humidity are common threats to turf. For more information about choosing grass seed, see our handout “Read the Label Before You Buy Grass Seed.”
TEN STEPS TO SUCCESSFUL OVERSEEDING
1. Before you begin, make sure the soil is evenly moist, neither too wet nor too dry. If your soil is very dry, water a day or two before seeding to soften it.
2. Mow to scalp existing grass to 1”-11⁄2”. Bag the clippings to help get the seed down into the soil.
3. If you have heavy clay soil or your ground is compacted, you may want to aerate and add gypsum. A core aerator pulls out plugs of soil and deposits them on the surface where they break down into a beneficial top dressing. Aerating every few years is good maintenance for cool-season lawns to alleviate natural traffic compaction. This allows better penetration of water, air and fertilizer. To further loosen heavy clay soils, add gypsum to your lawn after core aerating. (Rental core aerators are available at Johnson’s.) If you don’t core aerate, you can still improve your soil before seeding by applying Natural Guard Top Dressing with 100% humates. Top Dressing creates a soil-building process that results in more organic matter in the ground, increasing the nutrient uptake of roots so the fertilizer is absorbed better.
4. Good seed-to-soil contact is crucial in attaining desired results. Small areas can be worked with a rake. For large areas, a vertislicer (rented from Johnson’s Garden Centers) may be used to cut the seed into the soil. To avoid the “row” effect of new grass, overseed in one direction, then “cross-cut” at approximately 45° from the first run using 1/2 the recommended seed rate for each pass.
Recommended seeding rates are as follows:
Gard’n-Wise Premium Fescue: 3-5 lbs. per 1,000 sq. ft. for overseeding • 6-8 lbs. per 1,000 sq. ft. for new lawns
K-31 Fescue: 6 lbs. per 1,000 sq. ft. for overseeding • 10 lbs. per 1,000 sq. ft. for new lawns
DO NOT EXCEED the recommended rate. Seed sown too thickly is a breeding ground for disease. A small amount of debris will be left behind after vertislicing. Don’t rake it up unless there are very large clumps. A thin layer of debris will help keep the soil moist and protect the new seedlings as they grow.
5. Apply ferti•lome New Lawn Starter (9-13-7) with a broadcast spreader at the recommended rate. (You may borrow a spreader from Johnson’s with your lawn fertilizer purchases.) New Lawn Starter is high in phosphorus, which helps your grass seedlings develop strong roots and mature stems before rapid growth begins.
6. Moisture is vital to grass seedlings. The seed bed should never dry out, but should be kept constantly moist (not soggy). Water 3-4 times a day if necessary depending on weather conditions and soil type. Don’t water to the point of puddling or run off. Continue watering this way until the new grass is 11⁄2”. Then reduce the frequency of watering times, but water for longer periods of time.
7. Start mowing when some of the new grass reaches 3” tall. Don’t wait until all the grass reaches 3”. The sooner you start mowing the faster the grass will start to thicken. Don’t mow more than 1/3 of the grass blade at any one time and make sure the mower blade is sharp.
8. Spring overseeding: apply ferti•lome Green Maker (18-0-6) 30 days following seeding. This slow-release premium lawn food will provide all the nutrients needed to get new grass well established before summer. It is specially formulated for alkaline soils ... just like we have here in Kansas. Fall overseeding: apply ferti•lome Winterizer (25-0-6) 30 days following seeding and again 30 days later. These two applications will establish a healthy root system, build in winter hardiness, and give you early spring green up.
9. The cultivation necessary to plant grass sometimes brings weed seeds to the surface. To spot treat weeds, spray with ferti•lome Weed Free Zone after the new grass has been mowed three times.
10. Spring overseeding: apply ferti•lome Winterizer in September to encourage maximum growth during the peak growing season for cool-season lawns. Apply Winterizer again in November. This late fall application increases winter hardiness, keeps grass greener longer and promotes earlier spring green up. Fall overseeding: apply ferti•lome For All Seasons Lawn Food plus Crabgrass and Weed Preventer in January to mid April to feed your lawn while preventing crabgrass and other annual weeds from getting started in your turf.