Thin spots?

[Yossarian]

I have a spot in my yard where the grass is just kind of scraggly. This is a low spot in the yard where water tends to flow through when I get heavy rains, and water sometimes stands here. The rest of the yard looks great, but I can't seem to get the grass to thicken up here.

Could it be fungus? Soil compaction?

[andy10917]

Its called Drowning. Oxygen can't get into the soil and the roots are damaged or die.

Find a way to get rid of that standing water.

[Yossarian]

Yeah, I figured it was probably due to that. My soil is so heavy that water can stand for days if the rain is heavy enough. I've thought about trenching out this spot and adding in some better soil.

[Kevin Mac]

I have a problem with that as well in my back yard. What I've done is taken the soil that I've removed from other parts of my yard while landscaping and built up the low areas. It's a gradual process made even more difficult by my kids who love to jump in the mud, but it seems to be helping. Although, I'll eventually have to work at getting grass back in those spots. I've also read that core aeration is good for promoting drainage in areas like that. Certainly couldn't hurt.

[Dchall_San_Antonio]

When you get standing water for days at a time it suffocates the air loving microbes in the soil. What you are left with is a soil that resembles the soil around a swamp. You need to get this under control before that happens. The tell tale sign that it's already happened is that you can no longer grow turf grass.

I would start by spraying the entire yard with shampoo at 3-4 ounces per 1,000 square feet. That should help all the rain and irrigation to sink deeper into the soil. Follow up the shampoo with 1/2 to 1 inch of irrigation or rain. Since there is no rain in our forecast, give it time to dry out and do it in a few days. This will do more than core aeration will to help the water penetrate.

What would happen with your drainage if you raised the low spot to become level or even slightly higher than the surrounding area? If raising it will not push water into a building, then you should be able to do it. You can raise it by gradually by adding 1/4-inch of sand on top of the turf every week. Scalp the lawn, drop some sand, and push it around with a push broom to make it as even as practical. The grass will grow up through the light sanding from week to week.