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Written by Laura H., Somerset County Rutgers Master Gardener
As the days grow shorter and temperatures cool, plants begin to prepare for the long winter ahead. Turf, in particular, requires our attention at this time of year. Timely fall upkeep will pay off in just a few short months, with verdant green turf carpets in spring! Here’s the game plan:
- Weed control – Fall is an optimal time to manage many types of perennial weeds, which are difficult to control at other times of the year. Post-emergent herbicides are available which manage many types of broadleaf weeds. Ensure that the weeds you wish to control are listed on the product label.
- Soil evaluation – Having your soil evaluated provides valuable information on specific fertilizer and pH amendment needs. Your evaluation results will make recommendations that will prevent you from adding fertilizer or lime that you may not need. The Rutgers Soil Testing Laboratory tests soil for a nominal fee.
- Aeration – Aeration is an essential aspect of turf health in that it aids root growth by increasing access to oxygen. It mitigates soil compaction and provides a route for grass seed and amendments, such as lime, compost, and fertilizer to enter the soil. Aeration should be done when soil is somewhat moist. Aerators are typically set at 4” X 8” with ½” to ¾” tines; you will need to make several passes over your lawn for adequate aeration. They can be rented at hardware stores.
- Organic additions – Adding organic matter helps to provide turf with the materials that it needs to stay vibrant and healthy as well as to improve soil health. There is no need to purchase special organic matter for your lawn. Mulched grass clippings less than 1” long can be left in the soil, recycling nitrogen and other nutrients. Mulched leaves can also serve as organic amendments for turf. Place your mower on the highest setting, mow the leaf pile. Mulching mowers can cut up to 6” of leaf height at a time but large piles may require several passes. Leaf mulch can then be spread over the lawn where the fine pieces will disintegrate by spring.
- Overseeding – Select cool-season grass seed, such as fine fescue, tall fescue, perennial ryegrass, and Kentucky bluegrass when overseeding. Small patches can be managed by broadcasting seed with nitrogen fertilizer at a rate of one pound per 1000 square feet or by loosening the soil and sprinkling seed, then raking or covering over with 1/4 – 3/8” soil. For larger areas, slit seeders, available for rental at hardware stores, will effectively seed the lawn. Run the slit seeder twice, in perpendicular directions, at half the seeding rate indicated on the label for a well-seeded lawn. Mulch lightly with straw after seeding and irrigate until new grass is established. Begin mowing when the grass is at least 3” tall. Fertilize six weeks after germination.
- Dethatching – A layer of roots, shoots, and stems, called thatch, can build up over time. Thatch layers over 1” deep can harbor pests, make roots vulnerable to drying out and oxygen starvation, place turf and crown at risk of mower damage, and act as a barrier between the soil surface and the roots. Dethatching machines can be rented at hardware stores. Removing too much thatch can be detrimental to the turf, thinning it excessively. Thatch which is 2” deep or more likely is the home of turf roots so removing too much thatch will also remove plants. Plan to seed areas of thinned-out turf, if necessary. Never dethatch when turf is stressed by heat or drought.
- Fertilizing – Fertilize in September after the daytime high temperatures are below 90 F. A product with a mix of slow- and quick-release nitrogen, at a rate of one pound per 1000 square feet, will provide nutrients for stored energy as well as enhanced root development. Fertilizing in fall will also assist your turf in fighting off spring fungal diseases. A dense turf decreases the appearance of invading weeds. A November season-end fertilizing is also recommended, near or after the last mowing while the turf is still green. A quick-release nitrogenous product, at a rate of a half pound to one pound per 1000 square feet, will work best.
- Liming – Cool-season turf prefers a pH of 6.0 – 7.2. If the results of your soil evaluation showed that the pH is below 6.0, you will likely need to add lime to raise the pH to a level which is optimal for your turf. Drop or spinner spreaders are suitable for spreading lime. Pelletized limestone, which is limestone in larger particles held together by a water-soluble material and which is less dusty, may be a good choice. Use only the recommended amount and never use hydrated lime or burned lime, as it will damage established turf.
These tasks can be spread out into October, while the weather is still enjoyable. Keep thinking about that beautiful spring grass!
For even more information, see Rutgers Fact Sheet 102 Your Lawn and its Care.