Knowledgebase
Lawn help #879559
Asked July 31, 2024, 10:54 AM EDT
Oakland County Michigan
Expert Response
Check out the following articles on lawn overseeding:
Renovating A Lawn for Quality & sustainability-UMN
How to Overseed A Lawn-Iowa
Lawn Renovation & Over-seeding-UMass
You should only need about 1"/week, including rainfall, unless your soil is sandy. Irrigation should be done by 3PM to allow the grass to dry before evening reducing the possibility of disease conditions. Soil compaction might be a cause of bare spots. More info on how to determine the amount of water being applied & soil compaction here:
https://www.canr.msu.edu/news/how_much_water_does_your_lawn_irrigation_system_apply
https://www.canr.msu.edu/news/lawn-irrigation-tips
Smart Watering for Lawns-MSU
https://njaes.rutgers.edu/fs1313/ - soil compaction
https://extension.umn.edu/soil-management-and-health/soil-compaction#iron-deficiency-chlorosis-%28idc%29-1147265 - good info on soil compaction
https://turf.cals.cornell.edu/lawn/lawn-care-the-easiest-steps-to-an-attractive-environmental-asset/advanced-care/soil-compaction/ - lots of info here!
I suspect you have photographed evidence of Pythium Blight in your lawn. The photos show the mycelia (white cottony fungal threads) that are present in the early morning hours. Infected leaves become tan to brown, shrivel, and mat when dry. Pythium Blight affects all cool season turfgrass species and can be expanded by free water, clippings, equipment and shoes. Avoid mowing & walking on turf when fungal threads are present. Good soil drainage, minimal thatch, good airflow over the lawn, minimal nitrogen in hot, moist weather help prevent its occurrence. Fungicides can be applied preventatively. More info in the attached links:
https://www.canr.msu.edu/ipm/diseases/pythium-blight#gallery
https://turfpestlab.psu.edu/pest-profiles/pythium-blight/
http://ipm.illinois.edu/diseases/series400/rpd410/
https://www.extension.purdue.edu/extmedia/BP/BP-109-W.pdf
https://extension.umd.edu/resource/turfgrass-diseases-pythium-blight-fs-2024-0707/extension.umd.edu/resource/turfgrass-diseases-pythium-blight-fs-2024-0707
I note ragged edges on the grass blades in the photos => time to sharpen your mower blade! More lawn tips here:
Home Lawns | MSU Extension
Smart Lawns Tip Sheets-MSU
Benefits of Slow Release Lawn Fertilizers-MSU
How to Choose & Apply Grub Control Products-MSU
On Jul 31, 2024, at 4:09 PM, Ask Extension <<personal data hidden>> wrote:
For curative situations, research suggests that cyazofamid, mefanoxam, and propamocarb are the most efficacious options.
Mefenoxam (Subdue Maxx) and propamocarb (Banol) are time-tested materials that have proven to be very effective against Pythium blight. Cyazofamid (Segway) and fluopicolide (Stellar) are new products that reportedly are also very effective. (Purdue)
Here are some articles on reseeding/overseeding:
Lawn Renovation & Over-seeding-UMass
Renovating A Lawn for Quality & sustainability-UMN
How to Overseed A Lawn-Iowa
Establishing A New Lawn Using Seed (E2910)-MSU - this article is for new lawns (lots of similarities)
It's important to disturb the soil about 1/2" deep in the planting area and mix in compost or topsoil. Mix a bit of starter fertilizer in with the soil before seeding and strawing too.