A few tips for fixing bumpy spots in lawn
A few years ago I had a sprinkler system installed and a lawn seeded. In some places the grass is great, and in other places it is in clumps, which makes for a very bumpy and sorry-looking yard. What is the best way to remedy this situation?
I think the place I’d start is by trying to figure out why the grass isn’t thriving, at least in some spots.
The situation you described is often associated with drought. So first of all, you should make sure you are getting good coverage with the sprinklers. I’m sure they are hitting the grass, but it may be that some spots aren’t getting as much water as others. It is surprising how much water distribution can vary.
The best way to check this is to put a number of empty straight-sided cans out on the grass and to run the sprinklers for a set amount of time. (The cans don’t have to be the same diameter, they just have to have straight sides.)
Take a look at the amount of water in the bottom of each can. You’re looking for about the same amount of water in each. If some have a lot less than others, you may have to look at adding a sprinkler head or two or three.
If the amount of water in each can is pretty similar, then you should look at how you are irrigating. When you water, you want to soak the soil down to a depth of 8–12 inches, at least.
You can check that by running the sprinklers for whatever amount time you traditionally set, waiting an hour or two for the water to completely soak in, and then digging in several places to see how far down the water penetrated.
Dig several holes since water penetration can vary from spot to spot depending on the soil there.
If the water isn’t getting down far enough, you’ll have to run the sprinklers for a longer time. If that is what is needed, you may have to break your watering up into two or three shorter “squirts” to make sure the water soaks in and doesn’t just run off.
Like most folks, I have an automatic sprinkler system, so I program it to come on a couple of times on my watering days.
The second thing to check is how often you’re watering the lawn. You don’t need (or even want) the soil to stay consistently wet; it needs a chance to dry slightly before you water again.
In the heat of summer, I’d say most people are giving their lawns a good soaking once or twice a week. Of course, you don’t have to do it as often when it is cooler in the spring and fall.
Again, digging down to check the soil for moisture is the best way to go about this.
Once you’ve gotten the irrigation under control (if necessary) then it’s time to think about filling in those bare, patchy spots.
Unless there are large bare spots, which would lend themselves to re-sodding, the best way to go about this is to overseed the lawn. The best time to do this is when you have your irrigation water. Just be sure to provide water regularly so the seed doesn’t dry out.
Spread the grass seed over the thin areas, applying the seed a bit heavier than you’d normally do it if you were seeding a new lawn — figure 4–6 total pounds of seed per 1000 square feet.
You need to know what type of grass you already have. I’d say 95 percent of the lawns in western Colorado are varieties of Kentucky bluegrass. I like to spread a mix of half bluegrass and half perennial rye. You won’t be able to see a difference between the two but the ryegrass will germinate more quickly, stabilizing the seedbed and shading the bluegrass seedlings as they come up.
Over time, the bluegrass should crowd out the ryegrass, giving you a bluegrass lawn.
It is important to put a 1/4–1/2-inch deep mulch layer of a fine organic material on top of the seed to help hold moisture.
You’ll have to water a bit more frequently at first until the grass seed is well-germinated and rooting out pretty well. Then, wean it gradually back to your long-term maintenance schedule.