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How to Prepare Lawn for Overseeding

Keith Hardy - Bio Photo
Keith Hardy
Senior Editor

Keith has been involved in the gardening and landscaping industry for the past 21 years. From a jobbing gardener to running his own landscaping services....

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The secret to successful overseeding lies in the preparation. Ensuring that the ground is in the best condition for the new seeds to take and thrive will help avoid many of the common problems that can arise after overseeding.

How to prepare a lawn for overseeding is fairly simple. It is just a question of good planning and following best practices.

How to Prepare Lawn for Overseeding?

There are two parts to preparing your lawn for overseeding.  The first is the preplanning, which in itself will make the preparation more straightforward. The second is the actual preparation of the existing lawn. Making sure that all the necessary elements are right for the seed to take and germinate quickly.

Pre-Planning for Overseeding Your Lawn

Preparing for overseeding-lawn in need or renovation
lawn in need of renovation

Experienced gardeners will know better than most that having a plan at the outset is going to avoid headaches further down the line. Probably the key element is, when possible, deciding in advance when you are going to overseed. This is important because, under different climatic conditions, some varieties of grass seed grow more quickly.

If you are going to be using cool-season grasses, such as Kentucky bluegrass, you should be looking ideally to overseed in either the spring or the fall as they grow faster in cooler temperatures.

If you are going to be sowing warm-season grass, such as Bermuda grass, then you should be looking to overseed in the summer. 

Of course, local climatic conditions come into play, and these also need to be taken into consideration when planning. In addition, the landscape of your lawn plays a role. If large parts of the lawn are shaded, then these areas may be better with cool-season grasses.

Other factors that need to be pre-planned are the size and age of the seeds. It is important to check the date of your seeds as newer seeds germinate more quickly than old seeds. 

In terms of size and type of grass seed, cool-season grasses are larger than warm-season grass, which will mean that you will need more seeds if you are sowing warm-season grasses (see table below).

Finally, if top-dressing preparing your own compost is an excellent cost-effective fertilizer, you would have control over the contents. If preparing compost for top dressing, you might prepare the compost pile slightly differently from the general-purpose compost you would ordinarily prepare.

You might think that you don’t have three months for the compost to break down into finished compost. This time though, can be mitigated down to three to four weeks if you use the hot composting process.

Should I Aerate Before Overseeding

Having planned for when and the type of grass you are going to use when overseeding it is time to prepare the lawn. When the time comes, the first thing to do before overseeding is to aerate the existing lawn. There are lots of reasons to aerate a lawn, but in the case of overseeding, the task is to 

What is aeration and overseeding?

Aeration is the process of opening up the soil by punching holes, each of which should be around three to four inches deep and around a quarter of an inch in diameter. It sounds complex, but actually, a garden fork will do the job, although if you have a big lawn, you might purchase or hire a core aerator tool.

You can read more on aerating your lawn here, but, as good practice, you should aerate once a year anyway. The main purpose of aerating is to alleviate soil compaction and to allow more air, water, and nutrients to penetrate deeper into the soil. 

You would generally aerate a week or two before you top-dress and overseed. By aerating, the soil will be in good condition for overseeding, enhancing the chances of the seeds germinating quickly.

Scarify Lawn Before Overseeding?

After aerating, you should scarify the lawn to remove any existing thatch that is there. This will help the seeds find soil contact more easily when you overseed.

What Fertilizer to Use for Overseeding?

There are various ways in which you can overseed a lawn, from combining fertilizer with the seed to top-dressing before overseeding. The reason you would use fertilizer is that it bolsters the essential nutrients in the soil.

Many commercial firms will hydroseed, which mixes fertilizer, seed, and water, which is then sprayed evenly over the lawn, but if you are doing it yourself, then top-dressing before overseeding is probably the most effective way.

When top dressing, you can you various commercial fertilizers, but compost, preferably compost that you have made yourself, is the best top dressing that you can use.

Preparing fertilizer for overseeding

If you are going to use your own compost, you might think about preparing your pile to suit overseeding. Whilst general compost is fine you would have to filter out the larger pieces prior to top dressing.

If you prepare your compost in the correct way, you can avoid much of the filtering process. The key is to shred the organic material to as small a size as you can before building your pile. This should help provide a fine compost material that you can top-dress with.

Importance of soil moisture in preparing for overseeding

For the seed to take and germinate quickly, it is important that the soil contains a certain amount of moisture. However, the soil shouldn’t be soaking wet as this can drown the newly laid seed. 

Before overseeding, make sure that the soil is moist, about the feel of a sponge that has been wrung out. Once you have overseeded, you want to water the overseeded areas. regularly. 

Although you might not think it preparing a watering regime is important as you should avoid walking on any overseeded areas. If your lawn is large, this would mean setting up a sprinkler system before overseeding.

How Much Grass Seed Do I Need for Overseeding?

How to Prepare Lawn for Overseeding

The quantity of grass seed you need will depend largely on the grass variety and or the grass seed mix that you are intending to use. Below is a table that provides an estimate for some of the most popular cool-season grass types per thousand square feet. 

Grass Varietyper 1000 sq ft
Colonial bentgrass1-2lb
Kentucky bluegrass2-4lb
Chewing’s fescue4-8lb
Red fescue4-8lb
Perennial ryegrass5-10lb
Tall fescue8-12lb
Species Mixes5-8lb

In terms of the application, using a seed spreader is probably the most efficient way to put down the seed. A seed spreader is essentially a bucket on the back of a trolly that can be wheeled around the area that you are reseeding, distributing the seeds as you go. They are a relatively inexpensive tool that you can obtain from most hardware stores or garden centers. 

You would then rake the seeds to ensure that the coverage was as even as possible. A normal garden rake would do but if you have an extensive area, then a power rake would be useful.

Does overseeding work?

Provided that your existing lawn is properly prepared for overseeding, then there is absolutely no reason why it shouldn’t produce revitalized, healthy grass and, ultimately a healthy lawn at the end of the process. 

But preparation is just the start, having the correct follow-up watering regime and following good practices, such as avoiding walking on the overseeded areas for two to three weeks and avoiding mowing too soon, all play a role in the end result.

Is Overseeding Worth It?

If you are confronted with a deteriorating lawn, overseeding is an excellent and cost-effective way of reinvigorating it. It might seem that there is a lot of work involved, but actually, when you break it down, they are all fairly easy steps that can be taken. [1]

Other than cost, its main benefit is control. If your preparation is good, you have a lot of control over the whole process from the quality of fertilizer that is used to being able to mix grass varieties, especially if you have shaded areas on your lawn.

In addition, there is a sense of satisfaction that can be gained from successfully overseeding and seeing a beautiful, healthy lawn as a result.

Summary: How to prepare a lawn for overseeding

In terms of how to prepare a lawn for overseeding, a lot of headaches can be avoided if you have a good plan. Many of the processes involved actually can fit in with your lawn care program.

The soon you start to plan, the more efficient and successful your overseeding is likely to be. Deciding on the time of year and grass type can speed up germination, as does the proper preparation of the soil. Making sure it is in the healthiest state possible for the seeds will help them quickly thrive.


[1] University of Idaho: Lawn Renovation

Keith Hardy - Bio Photo
Keith HardySenior Editor

Keith has been involved in the gardening and landscaping industry for the past 21 years. From a jobbing gardener to running his own landscaping services. He is now dedicated to bringing you the latest in gardening news. Read more

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