Hello Scott,

I cannot offer any assessment of causality for your lawn turning brown without some photos and additional information. Please attach photos showing: overall lawn, closer photos of some of the brown areas and very close up photos of the blades and grass plants that are turning brown. Have you done a test dig in between waterings to see how much water is actually in the root zone of the grass plants? Grass plants need on average one inch of irrigation per week. Have you tested your irrigation to determine how much water you are actually delivering? Are the brown blades still attached to the crown of the plant or does it easily pull off the soil? It could also be a fungal infection. Southeast Michigan has had conditions very supportive of fungal growth this summer. Here is a summary of good cultural care that leads to the strongest grass plants: https://www.canr.msu.edu/resources/go_green_lawncare_tip_sheet

Now to your vincas. I can only comment on the plants in the photo. Curling, drooping leaves like that generally are indicative of underwatering or overwatering. What kind of soil did you use in the container? Does it have good drainage? Is the drainage hole clear and functional? How often do you water? Do you water over the foliage or under the foliage? Do you water every day no matter how moist the soil still is? Have you dug back some dirt to see the condition of the roots? Are they healthy white and fibrous or brown and mushy? One thing that this condition is indicative of is root rot infection exacerbated by overwatering: https://ask2.extension.org/kb/faq.php?id=840444

The only way to know exactly what is wrong with your annuals is to send a sample to the MSU Diagnostics Laboratory for analysis. This webpage identifies the services and fee structure for the Lab: https://www.canr.msu.edu/pestid/

This webpage has tips on how to take and ship a good sample: https://www.canr.msu.edu/pestid/submit-samples/

Hope this helps.