September Lawn Schedule: Controlling Weeds, Fall Fertilizer, Mowing, Watering Grass, and Lawn Aeration
Controlling Fall Lawn Weeds
Winter annuals, such as poa, henbit, chickweed, Carolina geranium, speedwell, and annual ryegrass, are all examples of weeds that can germinate in early fall and persist throughout the winter. Treat existing weeds and apply a pre-emergent for winter annuals in late summer. Tenacity is a pre- and post-emergent control that allows overseeding to still take place and germinate. Some herbicides may affect seeded turf, so check the label to make sure it is safe for seedlings.
Fall Lawn Fertilizer Tips
Conducting a soil test before fertilization is always recommended so that deficiencies or toxic levels of nutrients are within the soil. A soil test will determine what type of fertilizer is needed, as well as lime or sulfur applications. Fertilize cool-season lawns with an NPK fertilizer, like 16-4-8 lawn fertilizer. Apply 1 lb. of nitrogen per 1000 square feet.
Mowing in the Fall
Fall is an optimum time to sharpen mower blades if they have been used all summer. Dull blades damage the leaf tissue and give an off-color green to tan appearance. Blades that are not sharpened regularly can cause extra wear on the mower's engine. Maintain a mowing height between 2 ½” - 3 ½”. Never remove more than ⅓ of the leaf tissue in a single cutting. Leaving clippings on the lawn will recycle nutrients back into the soil.
Tips for Watering Your Grass
Continue watering with seasonal adjustments to the irrigation system to provide 1” of water per week. It is recommended to water in the early morning hours and complete a full cycle by 8 am. This will minimize evaporation and reduce the risk of diseases. Monitor the amount of moisture if overseeding, and don’t let the soil become too moist or overly saturated, as this will bring greater success for seed germination.
The Best Time to Aerate the Lawn
Air and water movement throughout the root zone profile will be very beneficial for soil health. Additionally, it will relieve compaction in the top 4” of the root zone profile for better growing conditions for newly seeded and established lawns. Nutrients will have a clearer pathway to go deeper in the soil to reach the roots, where they will be absorbed by the plant. Fall is the ideal time to aerate cool-season grasses.
October Lawn Schedule: Starter Fertilizer, Overseeding, & Watering Tips
Fall Overseeding Cool-season Grass
Before overseeding, mow the lawn short, around 2”. Rake to remove debris and thatch that could alter seed-to-soil contact. Dethatching will remove excess thatch buildup, as well as expose the soil for better seed-to-soil contact.
Establishing seed in either a new or an established lawn. Tall fescue often thins out in the summer months due to drought or heat stress, or disease, and requires overseeding to return to full density. Do not apply pre-emergent herbicides that will alter seed germination. Kentucky bluegrass and perennial rye grass can be used individually or in a blend of 2 or more different cultivars. The amount of shade that is present will play a factor in what type of grass one selects for overseeding.
Selecting seed to apply to the lawn requires detailed attention to percentage of live seed, percentage of germination rate, the amount of weed seed, and coated or non-coated. Look for seed that has a 97.5% purity or live seed; the higher the number, the better. The standard germination rate for new seed should be 80%, and the germination test date should not be longer than 9 months. The percentage of common weed seeds should not exceed 1.0%. Look for inert matter percentages to be less than 2% for high-quality seed, especially for cool-season mixes. Coated seeds, however, may have higher inert matter percentages due to the coating material.
Apply Starter Liquid Fertilizer
After seeding, apply a starter fertilizer program that focuses on rich phosphorus (P) and potassium (K). Simple Lawn Solutions 6-18-0 can be used if the soil is deficient of these nutrients at the time of seeding. Topdressing after fertilizing is beneficial for the germination of the seed. A light layer of compost works well to maintain moisture and increase seed-to-soil contact.
Watering a New Lawn
New seeds require constant moisture for the first 10-14 days. However, overwatering can lessen germination percentages. The goal is not to saturate, but to add short cycles of water throughout the daytime. Normally, 3-4 cycles of 5 - 7 minutes each cycle is sufficient, depending on weather conditions. Once the seed has germinated, increase the time and reduce frequency for deeper watering.
Lawn Fertilizer Schedule & Other Maintenance
Consider a light fertilization in October with a fertilizer designed for cool-season grasses, providing nitrogen and potassium fertilizer to help the grass recover from summer heat and prepare for winter.
Regularly rake or mulch fallen leaves, as leaving them on the lawn can smother the grass, block sunlight, trap moisture, and potentially lead to fungal diseases like snow mold.
Continue to mow as needed, gradually lowering the cutting height to around 2 to 2 ½ inches before the grass stops growing completely, which typically occurs when night temperatures consistently drop below 50 degrees Fahrenheit, around late October or early November.
November Lawn Schedule: Mowing, Leaf Cleanup, & Equipment Maintenance Tips
Mowing Frequency
Cool-season grasses can surge in growth in the fall due to cooler temperatures and better growing conditions. Mowing should continue during this time frequently, so no more than ⅓ of the leaf tissue is removed from the grass plant. Mowing frequency could increase to 4 - 5 times per week to maintain at the correct height. Once temperatures go below 50 degrees fahrenheit, the grass will slow its growth, and the frequency of mowing can be reduced.
Leaf and Debris Removal
Removing leaves from the lawn in the fall on cool-season grasses should be performed to prevent lawn suffocation. A thick layer of leaves that are left on the lawn blocks essential UV rays in the fall of the year. When sunlight is blocked, it disrupts the photosynthesis process and affects the growth of the lawn. Moisture that is trapped beneath the leaves increases the risk for lawn diseases and will require fungicide treatment. Leaves that are left on the lawn can alter the pathway of applied nutrients and reduce the overall amount that reaches the roots of the grass. Leaves that are not removed throughout the fall can break down and form an organic layer that could lead to compaction. Shredding or mulching breaks the leaves into tiny particles that will add nutrients back into the soil, which is beneficial to the lawn.
How to Winterize Lawn Equipment
Before storing gas-powered tools like mowers and string trimmers, clean them, empty the fuel tanks or add a stabilizer, change the oil and spark plugs if needed, and sharpen the blades. For electric tools, clean them thoroughly, charge batteries, and store them indoors.
The purpose of winterizing the irrigation system on the home lawn is to prevent damage to the pipes, valves, and heads if located in a region that experiences temperatures that are consistently below freezing. Water that is left in the line and not removed will expand in cold temperatures and run the risk of irrigation leaks, breaks, and improper operating pressure. Additionally, blowing out the system and insulating outdoor spigots will help protect them and increase the lifespan of the system.
Your Fall Lawn Care Guide
Taking these crucial steps in fall lawn care for your cool-season grasses ensures a thriving and resilient lawn in the spring. Aeration and overseeding improve soil health and density, while targeted fertilization and weed control promote vigorous growth and curb unwanted invaders. Protecting your investment further includes the vital step of winterizing your irrigation system, which prevents costly damage from freezing temperatures. By embracing this diligent fall checklist, you're not just maintaining your lawn but actively investing in its long-term health and vibrant appearance for seasons to come.
Sources:
https://info.supersod.com/sod-seeding/how-to-overseed-an-existing-tall-fescue-lawn
