Grass seed is where grass comes from, and if you are dissatisfied with the way your yard looks, then you might be tempted to scatter some grass seeds and ensure that some new growth covers up those patches in your yard that aren’t as flattering.
However, having too much grass seed can result in a yard that is overgrown, thick, and susceptible to diseases that can ravage your yard. If you have very thick and tangled clumps of overgrown grass, then you have put way too much seed down.
Can You Use Too Much Grass Seed?
Since you are in control of the amount of grass seed you end up throwing down on your yard, it is possible to use either too much or too little grass seed, and grass seed needs to be in the right amount. Grass plants need soil space to grow and develop together, and they also need space for their roots to spread and get anchored into the soil.
However, too much grass seed forces the excessive amount of grass plants into competition with one another for the limited resources of the yard, including soil space, sunlight, and water. The strongest will survive, but the grass will grow in very thick patches, and that doesn’t look too good for your lawn.
In order to make sure that you are putting down enough grass seed to grow a healthy and vibrant lawn, you will need to follow these steps to ensure your grass coverage will be just right.
What’s the Correct Amount of Grass Seed? 
In order to determine the correct amount of grass seed, you need to have three things: The bag of grass seed you will be spreading over your lawn, a lawn spreader. and basic knowledge of easy math. First, measure the length of your lawn by the width, and then multiply both numbers together. That is the area of your entire lawn, and now take a look at your lawn.
If you have a deck, a pool, a patio, or any other areas that will not be covered by the grass seed, measure the area of those items and then subtract them from the area of the lawn. What you have left is the total square footage of the lawn that will receive the seed.
On the back of your grass seed bag should be a list of numbers that connect the total square footage of your yard to the amount of seed you should be using. Depending on the companies you get your seed and your spreader from, they might have the information about your spreader settings to maximize the potential of your grass seeds.
If they don’t, or if you want to do more math, then you can use this formula: Application Rate = Amount Applied (pounds)/Area covered in square feet.
Then for a rotary spreader, start on the outside of the lawn and start to walk in a circular path towards the center. For a drop spreader, apply border strips along the edge and then apply the grass seed along the edge. Both methods might have you overlap the seeds a bit, but the overlap is good for the growth and will make sure your entire lawn is covered.
Once you have the lawn covered in seeds, water them daily and do your best to keep the soil moist for the seeds to have the best chance of germinating and sprouting.
What Does Too Much Or Too Little Grass Seed Look Like?
If you find that you have used too much or too little grass seed by making a mistake with the math or misreading a direction, then you will notice it on your lawn. As stated before, too much grass seed leaves grass in thick clumps. Too little grass seed will leave large patches of uncovered ground, ground which can be taken over by weeds.
In either case, you will know whenever too much or too little grass seed has been applied, just by looking at your lawn.
What to Do if You Use Too Much Grass Seed?
While you might decide that overseeding an area is something that you personally should fix, don’t underestimate how nature fixes itself after humans mess it up. The strong grass stalks will survive and the weaker grass stalks won’t, not to mention that some of the grass seeds will be blown away, eaten by birds and bugs, or simply won’t germinate.
Simply wait for the areas with too much grass seed to die off, and then focus on reseeding those areas with the correct amount of seed.
What Happens When You Use Too Much Grass Seed?
Too much grass seed creates thick clumps that can occasionally attract lawn fungus, which are brown and unsightly patches of grass. They might also appear as spots, slimy areas and mushrooms inside the lawn, and powdery blotches on your grass blades. Thankfully, removing the dead grass using special rakes, aerating and loosening the soil, and making sure your soil has the correct pH level can help overcome the problem of lawn fungus. Plus the disease also kills off most of the extra grass in the long run.
What Happens When You Use Too Little Grass Seed?
Too little grass seed leaves bald patches in your grass of dirt that are open doors for weeds. Weeds are unsightly and can damage the soil, preventing grass from growing even if you reseed the affected area. And no one wants to be on their hands and knees weeding all day just to keep their yard up. Too little grass seed makes your entire yard look uneven, so make sure to remove all the weeds and then focus on reseeding the affected area.
Other Factors to Consider When Growing Grass?
Of course, the amount of grass seed isn’t the only thing you need to worry about. Grass needs lots of water and moist soil during the first few weeks of its germination and life, so if you live in an area where heavy rainfall isn’t common, then you might have trouble getting a green lawn.
Grass also grows well in loose aerated ground that is also well-drained and has a pH level between 6 and 7, so make sure your soil is prepared to give the grass seeds the best chance of survival. Cleaning up debris or anything else that could impact the growth is also a good idea too.
Grass Seed FAQs
How Often Should I Water Grass Seeds?
For grass seeds, they should be watered every day, with the soil kept moist. Once they start germinating and sprouting, you can taper down your water usage to once every week, and then down to a few times a month.
Can I Spread Grass Seed on my Current Lawn?
If you are worried that you need a new yard to spread grass seed on to get the benefits, then don’t worry. You can spread grass seed on your current lawn without any trouble. If you notice any patchy spots on the lawn, don’t be afraid, just start planting seeds.
All you need to do is prepare your lawn for the extra seeds. Give it a good watering, mow the lawn at a low setting, collect the grass clippings, and rake away any debris. Then you just need to aerate the lawn and you will be good to go.
Can’t I Just Use a Grass Seed Mat Instead of Seeding?
Rather than scattering the seed haphazardly around your yard, you can use a grass seed mat to create a uniform look. You simply lay the mat down and the seed remains in place to grow, rather than getting blown around whenever the weather turns poor. Seed mats do work, but you do have to lay them properly and make sure they aren’t growing on top of one another.
It’s a more organized look than spreading the seed and potentially risking clumping, and if you don’t want to spend the work seeding your lawn the manual way they can be just as good. In any case, the seed mats are biodegradable, and will eventually degrade, leaving only the growing seedlings behind.
Final Thoughts
Seeding a lawn, whether you are seeding a new lawn to get a new look or adding more grass to an old one, is something that you can make work for patchy or undergrown lawns. You’ll be able to improve both the health of your grass and the look of your yard, as long as you don’t overseed.
Just remember, you should make sure to take your measurements and read the directions carefully, and also ensure that you aren’t overseeding. However, if you find that your lawn is covered in grass clumps and thick grass, then simply wait for the affected areas to cleanse themselves and then start again.
Once you know what too much grass seed looks like, you know what not to do, so next time you apply seed you can do it right!
Read our related grass seed articles:
- Where Does Grass Seed Come From? (All You Need to Know)
- How To Protect Grass Seed from Birds?
- What Can You Cover New Grass Seed With?
- How Long Do You Leave Hay On Grass Seed?
- Does Grass Seed Go Bad?
Jamie is the founder of The Backyard Pros. When he was 15 years old he started working at a garden centre helping people buy plants, gardening products, and lawn care products. He has real estate experience and he is a home owner. Jamie loves backyard projects, refinishing furniture, and enjoys sharing his knowledge online.