Cool season grasses – bluegrass, fescue and ryegrass – are best sown in early September. Seeds germinate and grow quickly in warm soil, and lawns seeded in the fall have the opportunity to establish, with little competition from weeds, before the winter freezes.
Seeding in early October may be successful if fall temperatures remain mild and weed competition remains low. October 15 is generally considered the last day to plant a lawn in the fall.
Before you seed your lawn, do a soil test to determine if any of the essential nutrients are lacking or if the soil’s pH is too high or too low. Take 10 to 12 random samples of your soil, 3 to 4 inches deep. Combine all samples, removing debris as you mix them.
From this composite sample, take 1 quart of soil and take it to your local extension office. This should be enough to fill a sandwich bag. Your sample will be sent to K-State for analysis and recommendations will be sent to you within a few weeks.
If soil amendments are recommended from your test, incorporate them into the soil before planting at the rates established by the soil test.
Preparing the seedbed is the most important step in establishing a healthy lawn. A well-prepared seedbed is essential for establishing a healthy and vigorous lawn. Chemicals, fertilizers, watering, and reseeding won’t make up for poor soil preparation, so don’t skip this step.
Soil preparation is the same for seeds, sod, clods or strands. At least 4-6 inches of nutrient-rich, well-aerated soil is needed to grow a healthy lawn. Ten to 12 inches of soil in this condition is best. Soils with a high clay or silt content compact easily, while sandy soils require frequent watering and fertilization, so pay attention to your soil type when taking your sample.
The properties of soil types can be improved by adding weed-free organic matter, such as peat, compost, or well-rotted or dehydrated manure.
The soil bed should be prepared several weeks before it is time to plant. Sometimes soil conditions and / or equipment limitations make it difficult to plow 10 to 12 inches deep. In these cases, to the deepest possible – the deeper the better. Use a plow, disc, tiller or other suitable equipment. After plowing and incorporating the nutrients, let the soil sit for a few days. Then perform a final leveling to smooth the surface of the soil.
If the proper electrical equipment is not available to prepare and improve the soil, hiring a professional service or renting the equipment is an option. Avoid over-tilling the soil, as this will destroy the soil structure.
Late plantings that fail are usually not killed by cold temperatures but rather by desiccation. Freezing and thawing of soil lifts poorly rooted herbaceous plants out of the ground, where they wither and die. Keep plants well watered to help maximize root growth before freezing weather arrives.
When overseeding and existing lawn, start by mowing the lawn short (1 to 1 1/2 inches) to help move the seeds through the canopy to the ground. Contact with soil and light (more abundant with short mown grass) increases the plant’s ability to germinate and grow.
To improve seed-to-soil contact, consider using an electric rake or a core aerator. Planter-slicer units are also available to cut the stubble and sow the seeds at the same time.
When overseeding; The principles of seed selection, sowing, watering and fertilization are the same as for new plantings. However, the seeding rate should be halved to account for the existing sod. Too much new seed can create competition and weaken the lawn. If only a few spots need to be reseeded, prepare those areas with a hand rake and then sow the seed as evenly as possible by hand.
Spread a thin layer of soil over the seed or work it with the rake.
Another option is dormant seeding during the winter. The seed does not germinate immediately. In the spring, when the soils warm, the seeds germinate. Begin dormant seeding when the average soil temperature is below 40 degrees, normally mid-November to late November.
This method will cause some seed loss (depending on soil temperature) and new plants will need to be closely watched and regularly irrigated.
Ariel Whitely-Noll is the Horticultural Officer for Shawnee County Research and Extension. She can be contacted at [email protected]