
Yes, you can over-fertilize your lawn. To be more precise, you can but you shouldn’t. There are several reasons why homeowners over-fertilize their lawns, and they’re more common than you think.
To help you avoid over-fertilizing your lawn, you must know which mistakes commonly lead to over-fertilization. If you’ve already applied too much fertilizer, you might still be able to save your lawn — I’ll tell you how.
Common causes of lawn over-fertilization
Fertilization is one of the secrets to having a beautiful green lawn. But if you over-fertilize your lawn, it can do more harm than good. So, if you don’t know much about proper lawn care, you may accidentally burn your grass or even cause environmental damage.
You don’t have to be a pro to know which mistakes to avoid when maintaining your lawn. Here are the most common reasons why homeowners tend to over-fertilize their lawns:
1. Having a “more is better” mentality

You’re wrong if you think giving your lawn a lot of plant food will quickly make it grow healthier and more beautiful. Many homeowners make this mistake and apply too much fertilizer at once because they also want to save time.
However, grasses have a limit to how much fertilizer they can absorb. Instead of speeding growth and enhancing results, over-fertilization can lead to nutrient imbalance and burn the grassroots.
Pro tip: Always stick to the recommended application rate and amount on the fertilizer label. Since fertilizers don’t have an overnight effect, be patient and never be tempted to apply more.
2. Ignoring or not following fertilizer instructions
Some homeowners find fertilizer labels confusing, especially since not everyone understands how the N-P-K (nitrogen, phosphorus, and potassium) ratio works. However, manufacturers put the instructions on their packaging labels for a reason. So, if you want to avoid over-fertilizing your lawn, it’s not advisable to skip reading this vital information.
Another thing to check is whether you’re using a quick-release or slow-release fertilizer.
- Since a quick-release fertilizer can rapidly deliver nutrients, applying too much can easily lead to nutrient burn.
- While a slow-release fertilizer provides a steady supply of nutrients over time, not following the instructions can still cause over-fertilization.
Pro tip: Only apply the recommended amount of fertilizer as instructed on the packaging label. You also may calibrate your spreader to help you distribute the fertilizer evenly.
3. Applying fertilizer too often or at the wrong time

Apart from applying too much, some homeowners also fertilize too often because they think it will help their lawns thrive and stay green year-round. What they don’t know is that fertilizing too frequently can cause a nutrient buildup in the soil and lead to poor grass growth.
Another thing to note is that there’s a time for everything. While it’s possible to do late summer lawn fertilization, it’s not advisable to fertilize during the peak of summer or late in the fall. Otherwise, the fertilizer will be ineffective and can cause stress to your lawn.
Also, the best time to fertilize your lawn will depend on the grass type:
- Warm-season grass: It’s best to fertilize warm-season grasses like bermudagrass and Zoysiagrass in late spring to early summer and late summer to early fall.
- Cool-season grass: On the other hand, you can fertilize cool-season grasses like tall fescue and Kentucky bluegrass in early to late spring and late summer to early fall.
Pro tip: To avoid over-fertilizing your lawn, follow a schedule that works best for your grass type and adjust your routine depending on the results.
4. Skipping the soil test

You may be able to get away with relying on your instincts for other things. But when it comes to fertilizing, it’s always a numbers game. And there’s no better way to determine the right amount of fertilizer needed by your lawn than a soil test.
Kit Smith, master gardener at the University of California Cooperative Extension in El Dorado County, agrees that testing the soil is essential before reaching for fertilizer. This way, you’ll know which specific nutrients are lacking in your soil.
Without a soil test, applying fertilizer would be like pinning the tail on the donkey. That’s why many homeowners who skip testing their soil end up applying too much fertilizer. Some even use fertilizers with high nitrogen content even though their lawn doesn’t need as much.
Pro tip: Do regular soil tests to check which nutrients your lawn needs. Don’t want to send a soil sample to your local extension office? You can use a DIY soil testing kit instead.
5. Not measuring your lawn size
You’ll be surprised how many homeowners make this mistake. They don’t know that lawn size is also a factor when calculating how much fertilizer to use.
Since fertilization relies on accurate numbers to be effective, you can’t simply guess the size of your lawn. If you overestimate your lawn size, you might end up accidentally applying more fertilizer than necessary. As a result, there’ll be an excess of nutrients in the soil which can inadvertently cause many lawn issues and diseases.
Pro tip: Not all homeowners have the patience to measure their lawn’s square footage. To ensure accurate measurements, you can hire a lawn care pro instead. Most pros offer lawn fertilization services for around $103 to $343 per service, which is worth every penny since you won’t have to worry about over-fertilizing your lawn.
6. Using fertilizers to fix other lawn problems

While a fertilizer can improve the health and beauty of your lawn, it’s not a quick fix for every lawn issue. Still, some homeowners think fertilizer is the right solution for all their lawn problems — from patchy spots to invasions of weeds like chamberbitter.
But applying fertilizer when the situation doesn’t call for it can make things even worse. You’ll simply overload your soil with nutrients without really solving the issue. Sometimes, lawn issues can be fixed by aerating your lawn, a simple adjustment in watering practices, or removing excess thatch.
Pro tip: Instead of always relying on your fertilizer, determine the underlying cause of the problem first.
Note: You’ll know you’ve gone a little too far with your fertilizer application if you notice the following common indicators:
- Wilting or yellowing grass
- Browning of grass tips
- White crusty buildup
- Rapid and excessive growth
- Pest infestation
FAQ about lawn fertilization
Can I use a combination of organic and inorganic fertilizers?
Yes, you can use a combination of organic and inorganic fertilizers. Doing so will allow your lawn to have the right balance of nutrients. However, you must still consult your soil test results to avoid over-fertilizing your lawn.
What should I do if I apply too much fertilizer?
In most cases, you’ll need to remove the excess fertilizer before reseeding or installing new sod to the damaged areas or bare patches. Check our detailed guide on “How to Fix an Over-Fertilized Lawn” to ensure you don’t accidentally add more stress to your lawn.
Can I fertilize and seed at the same time?
To get the most out of your fertilizer and avoid harming the grass seeds, don’t fertilize and seed at the same time. Wait around six to eight weeks for the seeds to sprout before applying fertilizer. But if your soil is deficient in nutrients, you may use a starter fertilizer with no weed preventer before planting seeds.
Let a pro maintain your lawn
Avoiding these mistakes that lead to over-fertilization can help maintain the health and lushness of your lawn. But with so many do’s and don’ts, fertilizing can be overwhelming.
While the rewards are worth the effort, not every homeowner has the time and patience to work on their lawn. When you hire a lawn care pro in your area, you can achieve the same, or even better, result without breaking a sweat.
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