Lawns look great when they are lush, green and neatly mowed. But there often comes a time when a previously green and glowing lawn will start to deteriorate and you have to take corrective action.
Sometimes lawns dry out in periods of drought or during prolonged periods of extreme cold. After thriving for many years, sometimes lawns fail to thrive because they are now getting too much shade. This is usually because trees have become established since the lawn was first planted. Pests sometimes have a detrimental effect on lawns, in the form of both insects and disease. Otherwise it may simply be that you have been under-watering your lawn or not feeding it enough. It could also be because the pH of the soil is inadequate – either too high or too low. The only way to establish this last possibility is to test the soil.
If only a small patch of lawn has deteriorated, or there are just a few bare spots here and there, you can probably reseed the lawn using the same type of grass that you planted in the first place. You may also be able to reseed (rather than renovate) if at least half your lawn looks reasonable. But if your lawn looks totally worn out, which can happen given the wear and tear garden lawns have to suffer, then you will either want to renovate or start afresh from scratch.
But whatever you decide to do, first get rid of the initial problem – if you can – for instance by using a herbicide to get rid of weeds or by correcting the soil. If you decide not to prune trees that are cutting out the light, perhaps because they now screen your home from a busy road, you will need to either replace or renovate the lawn by reseeding with a grass that will thrive in the shade.
What lawn renovation entails
When we talk about renovating a lawn we mean that we are going to replace the grass with a new grass that will take over what is already in the ground. This is done by reseeding with either:
- a new grass variety,
- an improved variety of the same species that is already in the ground, or
- a similar species of grass.
Just be aware that not all grass types can be successfully seeded into existing lawns.
When to renovate a lawn
While the perfect time to renovate a lawn will depend on the location of the site and the type of grass that is to be used for the renovation process, usually the ideal time will be early fall, which is also the best time to seed a new lawn.
However, cool-season grasses (the bluegrasses, fescues and perennial ryegrasses) can be successfully seeded any time between March and September. Warm-season grasses should only be seeded from April to July, while the weather is nice and warm.
How to renovate a lawn
If weeds have played a role in destroying the lawn, get rid of them by spraying with a non-selective herbicide that contains glyphosate. This will also kill off the existing grass, which is weed-infested anyway. Because glyphosate kills actively growing grass and weeds, it is best to spray during the growing season, and after the entire area has been thoroughly watered to promote growth. Let the herbicide dry and then allow between 10 and 14 days for the growth to die. If any areas remain green, spot spray them and continue the process.
When everything on the surface appears to be dead, mow the entire site as short as possible (to about about ½ inch) and rake all the clippings and other debris. Then use a dethatching machine or vertical mower with spinning blades to slice down through the lawn and into the soil so that any of the remaining lawn and weed is chopped up and the soil is thoroughly turned. Rake again and add the remaining loose material to your compost heap.
The next step is to aerate the soil, preferably by using a proper aerating machine that will pull out little plugs of soil and leave holes that effectively relieve compaction. You can hire these as well as dethatching machines. The little holes an aerating machine will produce are exactly what you need for the new seeds as well as the water and oxygen the soil needs. You could also use a power rake as long as you set it deep enough to expose the soil.
To ensure that the seed and soil make good contact with each other, many landscapers cover the dethatched and aerated soil with about a ½ inch of compost that has been mixed with properly screened topsoil mixed with compost. This effectively fills any low spots.
Then spread the seed on the newly exposed soil following the label instructions in terms of recommended rate of coverage – or even up to double the seeding rate recommended. Never spread the seed before covering with topsoil or compost.
Settle the seeds by smoothing with the back of a leaf rake and then compact lightly with a drum roller.
The last step is to water thoroughly, and to keep watering regularly. Remember that it is critical to keep the new grass seeds moist until their roots form and bind into the soil.
You won’t have to mow your new lawn until it is at least three inches high. At this stage you should only cut it back to two inches to allow it to continue to establish.
Check out this resource for more information on renovating a lawn.
Replacing bare spots in a lawn
If you have a few bald spots in your lawn you can either reseed them, following the same procedure described above, or you can shovel out some of the soil and replace it with a sod of established grass. If you plant with seed, it is helpful to cover the newly planted area with a bit of peat moss to help protect the seeds and retain moisture.