Homegrown: Sprinkler systems
I had a sprinkler system installed and my lawn seeded, but in some places the grass is great and in other places it is in clumps, which makes for a very sorry-looking yard.
What is the best way to remedy this situation?
The situation you’re describing is often associated with drought.
You’ll probably have to wait until you get ditch water, but you want to make sure that you’re getting good coverage with the sprinklers first of all. If they’re hitting the grass, it may be that some spots aren’t getting as much water as others. It is surprising how much water distribution can vary sometimes.
The best way to check this is to put a number of empty straight-sided cans out on the grass and run the sprinklers for a set amount of time. 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 an additional sprinkler head or two or three.
If the water in the cans checks out pretty close, then you’ll have to look at how you are irrigating. What you want when you water the lawn is to soak the soil down to a depth of at least 8–12 inches.
You can check that by running the sprinklers for whatever time you’ve traditionally run them, wait an hour or two for the water to completely soak in, and dig 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.
If the water isn’t getting down far enough, you’ll have to run the sprinklers for a longer time. If that’s what you have to do, you may have to break up your watering day into two or three shorter “squirts” to make sure the water soaks in and doesn’t run off.
The second thing to check is how often you’re watering the lawn. You don’t 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 that most people are giving their lawns a good soaking once or twice a week. You don’t have to do it as often when it’s cooler in the spring and fall.
Then it’s time to think about filling in those bare, patchy spots.
Unless there are large bare spots that would lend themselves to sodding, the best way to go about this is to overseed the lawn. You could think about starting the first part of April. You’ll have to provide water so the seed doesn’t dry out.
Spread the grass seed over the thin areas, applying the seed a bit heavier than you normally would if you were seeding a new lawn — figure 4–6 total pounds (for Bluegrass) of seed per 1,000 square feet.
You need to know what type of grass you already have there. 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 that you put a 1/4–1/2-inch deep mulch layer of a fine organic material such as peat moss on top of the seed to help hold moisture.
You’ll have to water a bit more frequently until the grass seed is well germinated and rooting out pretty well. Then, wean it gradually back to your long-term maintenance schedule.
Dennis Hill is the nursery manager at Bookcliff Gardens, http://www.bookcliffgardens.com. Send questions to Bookcliff Gardens, 755 26 Road, Grand Junction 81506; or e-mail info@bookcliff gardens.com.