Lawns may grow tired over the years, slowing their growth and making them susceptible to thinning and patchiness. Overseeding is an often-overlooked solution to spread new growth over an existing lawn. Although overseeding is a reasonably straightforward process, it does require careful preparation, execution, and maintenance.
To overseed your lawn, you need to test your soil, aerate and dethatch your chosen area and amend your soil for seeding. You should carefully select your grass species to fit in with your existing lawn, soil type, and climate. Overseeding improves the health of your lawn and removes unsightly patches.
Your lawn can regain its lush and green cover and reclaim its youthful splendor once again if you put in the work. You need not call in a specialist, as you can overseed your lawn yourself and repair your existing lawn by following a few basic procedures. If you wish to learn how to overseed your lawn, please read our handy tips to revitalize your tired garden.
What is Overseeding?
Overseeding is the process where gardeners’ renovate’ areas in their lawn by introducing lawn seeds to the existing lawn rather than reseeding the lawn altogether. Overseeding involves preparing the soil and seeding the area that needs attention to cover up any bare patches resulting from wear and tear, foot traffic, or the ravages of time.
Overseeding is different from seeding in that you sow over your existing lawn rather than prepare your lawn for planting from scratch. Experts recommend overseeding your garden if over 50% of your yard is in a healthy state. Otherwise, it is best to establish an entirely new lawn.
What Are the Benefits of Overseeding?
Properly preparing your lawn by first aerating and then overseeding your lawn has several benefits for your garden. Not only does proper overseeding pride visual appeal, but it can also help strengthen your existing lawn and make it more resilient to further a variety of potential threats. Benefits of proper overseeding include the following.
- Overseeding provides a dense and plush lawn surface and provides less competition from weeds that make a garden look shabby.
- Aeration and overseeding reduce compaction that inhibits proper root formation and growth.
- Choosing the correct type of grass seeds to overseed your lawn for your climate and soil texture creates not only a healthy-looking lawn but offers enhanced pest and disease resistance.
- Compacted and bare areas of your lawn affect proper water drainage and encourage weeds. By aerating and overseeding your lawn, you can prevent weeds such as yellow nutsedge, prostrate knotweed, and spotted spurge, which prefers wet and dense areas of open ground.
- Overseeding helps your existing lawn absorb water, air, and nutrients into the root zone to improve your overall garden health.
- Overseeding is a great way to introduce new grass species to your lawn if your current grass is not thriving as it should.
How to Overseed Your Lawn
A common mistake gardeners make is to assume that simply sprinkling grass seeds in the existing soil is enough to rescue their ailing garden. Simply placing seeds in your bare areas of the lawn will likely result in the same inadequate cover that you were attempting to eradicate. First, you need to address the underlying problem, or your lawn surface will continue to suffer.
Testing Your Soil for Reseeding
Experts often advise having a sample of your garden soil tested by your local County Extension Service for a fee. Despite the costs, professional tests may end up saving you money in the long run because you can then isolate precisely what your soil needs for your lawn and garden to flourish.
Alternatively, you can conduct a visual test by simply digging down into the soil and examining the soil structure and texture. Healthy soil should provide:
- Healthy topsoil up to a depth of at least 6 inches
- Healthy soil should not be hard-packed clay or porous sand and gravel.
The most common cause of an ill-performing lawn is that the soil is not deep enough and will not thrive until you add healthy organic-rich soil.
Ten Steps To Overseeding Your Lawn
If your soil appears healthy and provides enough depth of healthy topsoil, it is time to prepare your designated areas for improvement. You should consider the following steps when preparing your soil for reseeding.
1: Mow Your Existing Lawn
You should mow your lawn down to a height of around two inches high at the most to give your seedlings more chance to grow. It is important to remember to bag your clippings at this point because the clippings may prevent the seedlings from establishing themselves well.
2.Rake your Grass and Evaluate the Weed Population
You may require a nonselective natural herbicide at this point or dig in with a grape or grub hoe and eliminate the weeds in your chosen area. Weeds will compete with your new grass seedlings and hinder their growth.
3: Dethatch Your Chosen Area
You can dethatch your overseeding areas by removing dead and decayed grass from your designated patch. This moment is the time to ‘scar’ the soil surface for better seed-to-soil contact and penetration. You may either perform this manually with a rake or a ‘power rake’ or mechanical detaching machine. Ensure you scratch the surface of your soil in two directions to loosen the mat of dead grass properly.
4: Aerate your Soil Surface for Reseeding
Overseeding is one of the many activities made more effective after aerating your lawn. You may use a solid tine fork to penetrate the soil surface to 1″ to 2’’increase the seed on soil contact to ensure germination. Depending on your lawn size and your budget, plug aerators are an excellent choice for lawns. Plug aerators remove a core or plug of soil from your lawn and allow air, nutrients, and water uptake.
A good option is to rent a core or plug aerator machine because manual or spike aeration may cause further impaction in your lawn area by compressing the spaces between the spiked holes. However, mechanical aerators can be physically taxing, and those in good physical condition should operate them.
Important note: Aerating times differ according to your particular climate. The best time to prepare your soil for grasses such as fescue, bluegrass, and rye that favor cool seasons is between August and October. The best time to aerate your soil for grass seeds that favor the warmer climes, such as species like St. Augustine, Zoysia, and Bermuda, is April through June.
5: Amend your Soil for Reseeding.
Experts advise top-dressing your seeding area with compost, ensuring that your chosen compost provides nutrients such as nitrogen, phosphorus, and potassium. Also, ensure you have sufficient calcium, sulfur, and magnesium levels, which most grass seedlings tend to prefer.
At this stage, we also recommend adding a starter fertilizer, either immediately before or after you sow your new grass seed. See our article on using fertilizer when overseeding your lawn for more information on this step.
6: Select the Correct Grass Seeds
Before choosing your grass seeds for overseeding, you will need to identify the primary turf growing on your lawn. This identification is essential to ensure that your seeds are compatible with your existing lawn. If you are not sure, you could always take a sample of your grass to the local nursery for identification.
You may avoid potential disparities between your existing grass and new seeds by evaluating your grass type. For instance, coarse tall fescue won’t fit with Kentucky Bluegrass nor centipede with your St. Augustine. Also, ensure that the seed type is correct for your area, climate, and soil type to allow your seedlings the best chance of growth.
7: Begin Overseeding
Spread your chosen seed with a broadcast or drop spreader paying attention to the spreader rate listed on your seedboxes or packets. Only roughly half of your seeds will germinate, so it is essential to place the correct amount of seeds in your chosen area. A good tip is to walk in rows at a steady pace and overlap your rows by a couple of inches.
8: Dress Your Seeds
Once you have sown your seeds, experts recommend that you apply a modest application of starter fertilizer to kick start your seedling’s growth. You can add this fertilizer either before or after sowing the seed. You may top-dress your seeds in a thin layer of compost and follow up by fertilizing the lawn with some quick-release nitrogen fertilizer after four weeks to boost your seedling’s growth.
9: Water Your Seeds Well
Your seeds need to remain moist at all times in the germination process, so it is crucial that you water your seedlings regularly. The rule of thumb is that you should water every day that there is no rain and twice per day in very hot weather.
10: Protect your Vulnerable seedlings
People, pets, and other traffic can disturb your seeds’ growth, so you should ensure the seeds are safe until they have established themselves. Birds are also a menace and will quickly devour exposed seeds if given a gap. While your seeds are vulnerable, many experts suggest covering your overseeding patch with an all-purpose garden fabric you may find in nurseries and garden supply outlets. You could also opt to use straw to cover the grass seed, which acts as an organic mulch.
Lay the fabric over your seeds, and the material offers protection from both birds and the elements. Be aware that these fabrics may harm your seeds in hot weather and are more suited to cooler weather.
How Do You Maintain Your Overseeded lawn?
- Watering is imperative for grass seed germination, and you should water your seeds from the time you planted them every day until they begin to germinate (this may take up to two weeks.)
- Limit traffic and activity such as mowing until the seedlings have adequately established themselves in the soil.
- Once your grass seedlings have sprouted, continue watering lightly but allow the soil to dry slightly before rewatering. Too much moisture at the seedling stage could be detrimental to your new grass and cause root disease.
- Once your reseeded grass has reached a height of 3-4 inches, mow the new lawn with a sharp mover blade when the grass is not wet; mowing wet grass is a bad idea for a number reasons. Avoid making sharp turns in the newly grown area and aim to mow straight across your reseeded patch. Continue to follow a regular mowing schedule.
- Be careful not to use herbicides for at least 6-10 weeks after overseeding, as this will damage the newly sprouted grass seedlings.
When is the Best Time For Overseeding?
Timing is everything when it comes to successful overseeding. Cool-season grasses favor late summer to early fall when planted in the northern regions. There is still enough warmth in the soil to promote germination in the fall. The temperature is moderate enough to allow the seeds to establish themselves before the winter cold arrives.
The soil moisture levels are more constant at this time of the year, and the cool air enhances seed growth. Many of the more invasive weed species such as crabgrass and nutsedge are less active in fall, giving your seedling less competition.
Those who live in the south should overseed from late spring because warmer season grass needs the warmer soil temperatures to establish themselves properly. For a green lawn in winter, overseed your southern lawn in fall when temperatures drop below 65°F, and your warm-season lawn starts to fade.
What Seed Should I Choose For Overseeding?
The type of grass seed you choose for overseeding will ultimately depend on the region that you live in and the weather conditions that your region tends to see. We have provided guidance on picking the best grass seed type in our article Best Grass for Overseeding.
If you live in the southern climes, your best grass seed option is the warm-season variety. They maintain their color well through the warm weather but do not thrive in the cooler seasons. Popular war season species are the Bermuda and St. Augustine grass varieties.
If you live in the cooler parts of the US, your best option is to choose the cool-season grass species, which are hardy and flourish through spring and fall. These grass species tend to slow their growth in the warmer months and are an excellent option for a garden with shade. Popular examples of these grasses are the fescue, Kentucky bluegrass, and perennial rye grasses.
If your garden is looking threadbare and still has areas of healthy grass, overseeding is an excellent option. Overseeding not only provides greater cover and visual appeal, but it also improves the health of your existing lawn, corrects soil impaction, drainage, and unsightly ‘thatching’ of your lawn surface. Proper preparation is time-consuming, but the effort spent offers the reward of green and rolling lawn to enjoy and admire.