Knowledgebase
Yellowing of fescue grass lawn #265119
Asked July 26, 2015, 10:57 PM EDT
I scraped and started over on my south-facing, 1,000 SF front lawn thee years ago. After removing the old sod, I tilled in 4 cy of compost and seeded with tall fescue grass seed. After battling the birds eating the grass seed for three years the lawn came in thick and looked great this spring however upon the first day of 85 degree + summer day the grass has turned yellow.
I planted fescue under the assumption it was supposed to be heat tolerant and low water needy. Watering seems to have little effect in bringing back the green lawn; the yellow grass looks like its dying and under-watered. Might there be another problem occurring?
Arapahoe County Colorado
Expert Response
Photos are always helpful so we can see what you are describing. It is helpful to see if the yellowing is widespread, or just in a specific area; if the yellowing is affecting the entire blade or the very tips, full sun or shade, etc. Without seeing photos, there may be several possibilities:
Tall fescue is considered a cool-season grass, but unlike Kentucky bluegrass, it does not go into dormancy during extended hot periods. However, if it goes through an extended period of drought (lack of watering) in hot summer temperatures, it will begin to die back and start to display a patchy, dry look.
Tall fescue grass is "considered" drought tolerant but it DEPENDS. IF you have the type of subsoil where the roots can penetrate at least 3 feet deep and draw moisture from, then it would need less surface watering. If the roots cannot grow this deep, then tall fescue will need as much, or more, water than Kentucky bluegrass.
A common problem of tall fescue is mower leaf shredding. The leaves are tough and will shred if the lawnmower blade is not kept very sharp and in good adjustment. Severe cases of shredded leaf tips can cause a lawn to have a brown or yellow-ish tint so consider inspecting the grass blades. See attached photo of leaf shredding.
Nitrogen deficiency can sometimes cause lawns to appear less green. The following link has a fertilizer application schedule for tall fescue lawns. It also has great information on overall care to keep your lawn healthy. Do not fertilize your lawn now, but consider following the application schedule.
http://www.ext.colostate.edu/mg/gardennotes/551.html
Finally, Ascochyta Leaf Blight has been a problem this year and can affect tall fescue lawns. See the following fact sheet and blog for more information on this fungus.
http://csuhort.blogspot.com/2015/07/what-pain-in-ascochyta.html
http://www.ext.colostate.edu/pubs/garden/02901.pdf
Additional links for helpful information:
http://www.ext.colostate.edu/pubs/garden/07199.pdf
http://www.ext.colostate.edu/pubs/garden/07211.pdf
Here are two links to selecting the right grass for your lawn:
http://www.ext.colostate.edu/mg/gardennotes/561.html
http://www.gardencentersofcolorado.org/pdfs/care_sheets/Selecting_the_Right_Grass.pdf
