Is your lawn looking worse for wear? Extreme temperatures experienced this year both in winter and summer, along with periods of summer drought, have taken a toll on Piedmont lawns.
by NC Cooperative Extension
Lawns that were already stressed due to soil issues such as compaction, pH imbalance, and low nutrient levels, are showing the most severe damage.
Thin turf, bare patches, and a proliferation of weeds are all signs your lawn could use some extra care. Take heed – fall is the time to undertake several important lawn maintenance tasks that can put your yard back on the path to health and vigor.
Work With Nature
If your lawn needs help, take time to evaluate the underlying problem before taking action. The most important question you need to ask is, “Am I trying to grow turf in an area that turf is not adapted to grow?”
One of the most common mistakes is trying to grow turf in areas that are too shady. All types of turfgrass need sun, even those promoted as shade tolerant. Shade intensity is as important as the amount of time the area is shaded each day. Areas where over 50% of sunlight is prevented from reaching the ground all day, due to trees, buildings or other obstructions, are simply too shady for any turf to thrive.
Solutions for shady areas include mulching to create natural areas or planting shade tolerant plants such as Lenten rose (Helleborus), ajuga, ferns, and plum yew (Cephalotaxus).
Another location turf is doomed to failure is any area that receives repeated and concentrated traffic. Turfgrasses can tolerate being walked upon but have their limit. Narrow paths that concentrate traffic are not a good location for turf. Repeatedly walking upon the same area over and over compacts the soil and slows the recovery rate of the grass. A better option for areas that receive heavy traffic is to install a path of mulch, rock, or stepping stones.
The Soil Is the Secret
If your lawn receives plenty of sun, yet the turf still struggles, investigate the soil conditions. Compaction is one of the most common causes of poor turf performance. Clay soils are easily compacted, especially during home construction. Builders will often spread a few inches of topsoil on top of compacted clay soils to help grass establish but this does not provide a sufficient root zone for healthy turf. You can check for compaction by pushing a shovel into the soil. If it is hard for you push the shovel in at least six inches deep, it will also be hard for turf roots to grow adequately.
Core aeration will help alleviate light to moderate compaction. Core aerators remove plugs of soil, opening channels that allow water and air to better penetrate the root zone. Tall fescue lawns should be aerated in September, before overseeding. Wait until May or June to aerate lawns planted in warm season grasses such as Bermuda, zoysia or centipede. Core areators can be rented from most equipment rental centers. Many lawn care companies also offer this service. Learn more about aerating your lawn: https://pubs.ext.vt.edu/430/430-002/430-002_pdf.pdf
Soil pH is another factor that can limit turf performance. Under natural conditions most soils in the piedmont have a pH around 5.0, which is considered moderately acidic. Turfgrasses grow best when soil pH is between 6.0 and 6.5. In acidic soils, soil pH can be increased by adding lime. Fall is a good time to surface apply lime, if it is needed. To determine if your lawn would benefit from lime and how much should be added, submit a soil sample to the NC Department of Agriculture’s soil test lab in Raleigh. Soil sample results will tell you the soil pH, if lime is needed and how much to apply, the soil’s nutrient status, and what type of fertilizer should be applied. Samples submitted between April and November are analyzed at no charge, while samples submitted during the lab’s peak season of December – March are charged $4 per box. Soil sample boxes and forms are available from any NC Cooperative Extension office. Learn more about soil testing: http://chatham.ces.ncsu.edu/soil-testing-for-lawns-and-gardens/
Whether or not your lawn should be fertilized in fall depends on what type of turf you have and your soil test results. Grasses should be fertilized with nitrogen when they are actively growing. Cool season lawns such as tall fescue that grow during the fall and spring are fertilized with nitrogen in September, November, and February. Warm season grasses such as zoysia grow during the summer and are fertilized between April and August.
Fertilizing warm season lawns with nitrogen in fall increases the risk of winter injury and encourages weeds and diseases. By leaving your grass clippings on the lawn instead of bagging them, you can reduce the amount of nitrogen fertilizer your lawn requires by 25%. For specific recommendations on when to fertilizer your lawn and other timely tips, check NC State’s lawn maintenance calendar for your turf type:
· Bermuda: http://www.turffiles.ncsu.edu/turfgrasses/bermudagrass
· Centipedegrass: http://www.turffiles.ncsu.edu/turfgrasses/centipedegrass
· Tall Fescue: http://www.turffiles.ncsu.edu/turfgrasses/tall-fescue
· Zoysiagrass: http://www.turffiles.ncsu.edu/turfgrasses/zoysiagrass
Overseeding Tall Fescue Lawns
If your tall fescue lawn needs to be overseeded, mid-September is the best time to do it. First be sure to diagnose and correct any underlying problems. Core aerating before overseeding will result in better germination and establishment. Be sure to select a tall fescue mix that includes varieties recommended for North Carolina. A list of these varieties can be found in NC Extension’s Carolina Lawns publication (page 9) along with complete instructions for establishing, renovating, and caring for your lawn: http://www.turfgrass.ncsu.edu/Articles/Bruneau_A/2008/Carolina_Lawns.pdf
When purchasing grass seed, check the label before you buy. Important information to look for on the seed bag label includes:
· Name of grass cultivars included in the mix (for example, Mystix, Legitimate, and Arisotle on this label) – look for varieties recommended by NCSU <http://www.turffiles.ncsu.edu/Files/Documents/Presentations/2014%20Recommended%20Tall%20Fescue%20Cultivars.pdf> based on their turf variety trials. Top performers include Wolfpack II, Talladega, Faith, 3rd Millenium, Rebel IV, and Gazelle II.
· Germination % (85% on this label for all three varieties) – higher germination rates mean more seeds come up.
· % Weed Seed – choose mixes with very low weed seed levels (less than 0.25%).
· Sell by Date – fresher seed generally have higher germination rates. Choose seeds packaged for sale this year or next year. Avoid seed that have already passed the sale by date.
Tall fescue is typically seeded at a rate of 5 to 6 pounds per 1000 square feet. Do not apply pre-emergent herbicides before seeding – these will prevent your grass seed from sprouting. Use post emergent herbicides with care – read the label to determine if and when they can be used on newly seeded or recently established lawns. Learn more about overseeding cool season lawns: http://www.turffiles.ncsu.edu/alerts/grasses/time-for-fall-seeding-of-cool-season-grassestall-fescue-and-kentucky-bluegrass-
Warm season grasses will not establish if seeded in fall. Wait until spring to seed, sod or plug warm season lawns. If you are considering changing your lawn to a different turf type, NC State’s grass selection tool can help you determine which turf will work best for your conditions and preferences: http://www.turffiles.ncsu.edu/tools/grass-selection
Find answers to many common lawn care questions in these great online resources:
· Moss in lawns: http://pubs.ext.vt.edu/430/430-536/430-536.html
· Managing white grubs: http://www.turffiles.ncsu.edu/insects/white-grubs
· Managing weeds in tall fescue lawns: http://www.clemson.edu/extension/hgic/pests/weeds/hgic2309.html
· Managing weeds in warm season lawns: http://www.clemson.edu/extension/hgic/pests/weeds/hgic2310.html
· Managing brown patch: http://www.turffiles.ncsu.edu/diseases/brown-patch
Charlotte D. Glen is the Agriculture Agent – Horticulture for NC Cooperative Extension, Chatham County Center. Contact her at [email protected] or 919-542-8202.