Starting a new lawn (successfully) is a combination of science and lots of TLC. As any green thumber knows, fertilizing is essential to keeping an established lawn looking lush. But what about a brand-new one? Do you even need to fertilize it, and if so, how? This guide to fertilizing new grass will tell you everything you need to know about growing a perfect lawn from scratch.
Get ready to be a lawn-growing pro.
Here’s the secret: Before you lay down grass seed or new sod, give your soil a boost of nutrients with starter fertilizer. It’ll be the extra push your new grass needs to grow into the lush, green carpet of your dreams. However, it’s not enough to just grab any bag of starter fertilizer off the shelf.
Read on to learn how to choose and apply the best starter fertilizer for your new lawn.
On this page:
- How to choose fertilizer for new grass
- How to fertilize new grass: A step-by-step guide
- Other considerations
- FAQ
How to choose fertilizer for new grass
Before you go fertilizer shopping, you need to know what you’re looking for. For new grass, you’ll want a starter fertilizer. Starter fertilizer is a special blend of nitrogen, phosphorous, and potassium, otherwise known as the NPK ratio, that’s designed specifically to boost growth in brand-new grass.
Out of the three, phosphorus is the most important nutrient for new grass since it helps develop a strong root system and speeds up germination.
In fact, the majority of starter fertilizer ratios will contain more phosphorus and less potassium (potash) than regular lawn fertilizer.
Learn more about the NPK ratio and choosing the perfect fertilizer for your grass in our guide to what to look for in your fertilizer.
Why is starter fertilizer necessary for new grass?
Think of it this way: You want your grass to reach its full potential, right? Well, the soil plays a critical role in making that happen.
For the most part, the soil needs time to break down organic material so that a plant can access essential nutrients. At the onset of growth, however, it’s not always easy for the roots to reach far enough down to make use of these nutrients. Starter fertilizer fills in the gaps and gives grass seedlings everything they need to thrive right from the beginning.
As phosphorus is a nutrient that doesn’t move around much in the soil, adding starter fertilizer before planting will ensure that the young plants have immediate access to it and can establish roots much faster. Many starter fertilizers contain a high concentration of both phosphorous and quick-release nitrogen to boost root and shoot growth at the same time.
Some of the best fertilizer NPK ratio options for new grass include 10-10-10, 16-8-8, and 20-10-10. Find some examples of starter fertilizers in the table below, and check out our reviews of the best lawn fertilizers on the market for more options.
However, it’s best to know exactly what nutrients are missing from your soil before you commit to buying any type of fertilizer. After all, not every bag of starter fertilizer will be right for your lawn. Learn about your soil’s composition and nutrient content with a soil test.
Test your soil to choose the right fertilizer
The first step towards healthy and stunning grass is a soil test. If you don’t know what’s going on in the ground, it’s hard to make an informed decision regarding fertilizers. Armed with the results from your soil test, you’ll be able to identify exactly which nutrients should be added and at what concentration.
You can purchase a DIY soil test kit or reach out to your local Cooperative Extension office for soil testing in a lab. Typically, DIY kits produce nearly instant results but don’t tell you much, while test results from a lab can take weeks to come in but include an extremely detailed report, along with fertilizer and soil amendment recommendations.
Pro tip: If the soil pH is not appropriate for your turfgrass type, you can adjust it by adding either lime for a too-low pH or sulfur for a too-high pH.
How to fertilize new grass: A step-by-step guide
Now that you have a better understanding of starter fertilizer, here’s a step-by-step guide on how to apply it with ease. From prepping the soil to selecting the right fertilizer and spreading it when the time is right, these simple tips will help ensure your new lawn project is successful.
Step 1: Prep your soil accordingly
You wouldn’t go in for a job interview wearing sweatpants, would you? You have to prep your soil before adding starter fertilizer and planting new grass, just like you would clean yourself up before meeting someone new.
Start by decluttering – get rid of any sticks, debris, weeds, or pests. Ensure the area is level and sloping a bit so the water can run off easily. After that, spread a two-inch layer of organic material, such as compost or well-rotted manure. This natural layer not only improves the fertility and aeration of the soil, but it’ll also act as a buffer for the fertilizer.
Pro tips:
- Check the forecast before you fertilize, and make sure there’s no rain in sight. Since you can’t control the weather, it’s best to be proactive. If rain’s on the radar, your fertilizer could get washed away.
- To maximize fertilizer absorption, give your soil a good soak a few days beforehand. Having the right amount of moisture will help your seeds sprout faster. You can measure the moisture content by sticking a long stick into the ground — if it’s easy to insert, your soil is ready for fertilizer. If not, it may be too dry.
Step 2: Grab the right lawn starter fertilizer
As we mentioned earlier, the right fertilizer for you may differ depending on your soil results. In most cases, however, a high-phosphorus starter fertilizer like 10-10-10, 20-10-10, or 16-8-8 should do the trick. Whatever you decide, make sure the product you’re using is suitable for the type of grass you’re planting.
Pro tips:
- If you want to sow seeds, ensure the nitrogen and phosphorus levels are balanced. Your grass needs equal amounts of both to thrive. But if you’re laying sod, you can add a bit more phosphorous to the mix. It’ll help the roots become firmly rooted quickly.
- Do some math and learn precisely the amount of fertilizer you’ll need to cover the entire area. As a rule of thumb, apply fertilizer at a rate of 0.5 to 1 pound of nitrogen is per 1,000 square feet.
- Don’t overfertilize. Overdoing it can cause nitrogen burn and be detrimental to your grass seedlings.
- There are two types of starter fertilizers: granular and liquid fertilizers. Generally, the quick-release nitrogen in liquid fertilizer is absorbed faster, while a granular fertilizer may take a bit longer.
Step 3: Spread evenly
Time to whip out the fertilizer spreader (for granules) or sprayer (for liquids). Whether you’re using a granular or liquid starter fertilizer, spreading it evenly across the whole area where your future lawn will be to make sure every blade of grass reaps the benefits.
Begin in the corner of your future lawn and move across the space in overlapping strips, going from one side all the way to the other and back again. Remember, when you come to the end of each strip of soil, turn the spreader off before you turn for the next pass, or you may end up with an uneven application.
Word of caution: Granular fertilizers can be tricky to spread, and if you’re not careful, they can be real scorchers – meaning they can scorch young, delicate plants if you’re not careful. So it’s super important to follow the instructions on the fertilizer packaging so you know how best to apply it and in what amount.
Pro tips:
- After you spread the fertilizer, work it into the soil about four to six inches deep. This will get rid of any potential uneven applications and allow fertilizer to reach deeper down and promote strong root growth.
- If you’re sowing seeds, apply the fertilizer right before or right after planting – depending on which works for you. If you apply after, all you have to do is use a fertilizer spreader and water it in. For sod, you’ll need to apply the fertilizer before planting.
- Try not to spill any fertilizer – a spill on the grass could burn it, while a spill on an impermeable surface (like a driveway) can lead to harmful runoff.
- For granules, you can choose either a drop-type spreader or a broadcast spreader. Whichever you pick, calibrate it according to the manufacturer’s instructions.
- Fertilizing by hand is still an option, but if you go this route, use gloves! Gently spread the fertilizer in a sweeping motion while walking backward. It can be tough to get even coverage with this method, so keep that in mind.
- Apply the starter fertilizer early in the morning or late in the evening when the temperatures are cooler. You don’t want your fertilizer to evaporate before it absorbs into the soil.
Step 4: Lay the grass seed or sod
If you’ve made it this far, your fertilizer is already working its magic, and you can move on to the next step, which is sowing new grass seeds or laying sod. Whether you choose the former or the latter, make sure the soil is moist before planting, as this will make everything easier and help the new grass begin to lay down roots.
Pro tips:
- Remember, applying starter fertilizer before you sow your grass seed is usually the best approach. Want to use it after planting the seeds? Sure, that’ll work too. But generally, pre-application is the way to go!
- Finally, don’t forget to give your grass some time! It can take up to 30 days for it to germinate, so keep those roots watered and healthy in the meantime.
Step 5: Water with care
Watering is a critical part of establishing new grass. Too little water can cause it to dry, while too much water can drown the grass.
Here’s how to water new grass after fertilizing:
- For the first week, water your grass twice a day for 5-10 minutes each time. After the first week, you can gradually reduce the frequency until you reach a normal lawn watering schedule of 1-2 times per week.
- Water early in the morning (before 10 a.m.) so the water has time to soak into the soil before the sun evaporates it. You can also water in the evening, after 6 p.m., but then your grass will likely stay wet overnight, which could cause fungal lawn diseases to grow.
Step 6: Fertilize established grass with regular lawn fertilizer
About six to eight weeks after you apply starter fertilizer and plant your new grass, it’s time to fertilize the now-established grass with a regular lawn fertilizer.
Starter fertilizer for established grass? That’s not the best idea. While it won’t hurt your existing lawn, it won’t really do it any favors, either. For mature grass, it’s best to use a well-balanced lawn fertilizer with low phosphorus levels and increased potassium and nitrogen for a darker green hue and improved resistance to drought, pests, and disease.
Pro tips:
- Applying fertilizer to an established lawn is a little different from using starter fertilizer. See our Fertilizer 101 guide for tips on fertilizing established grass.
- Don’t forget to check the directions on your spreader before you use it!
- Keep your lawn mowed to promote strong, healthy growth.
- When you’ve just seeded your lawn, hold off on spraying herbicides or using weed and feed products. They’ll stop the root development, and you don’t want that for a newly seeded lawn.
Other considerations
Although starting a new lawn may seem like a long and daunting process, it’s not. Take it one step at a time, and plan ahead based on your soil test results and turfgrass type to get the most out of your starter fertilizer applications. Here are some further pointers to keep in mind when growing new grass.
Go organic
Who doesn’t love healthier soil? If you’re looking for a natural alternative to synthetic fertilizers that won’t hurt the beneficial microorganisms in your soil, organic fertilizers are the way to go. They don’t contain any harsh chemicals and are much friendlier to the environment. Plus, they’re less likely to overload your soil with too many nutrients.
Mow your new turf right
New grass needs time and attention. Don’t mow your new grass until it’s at least 3-4 inches tall. Keeping the blades of grass at a height of 2 to 3 inches is recommended. Mowing any lower than that could cause the grass to become susceptible to damage and disease.
Pro tip: Don’t mow for at least four weeks after planting. It takes a bit for roots to begin spreading out underground. If you cut too early, you risk pulling out the grass’s new and fragile roots.
Understand the difference between regular fertilizer and starter fertilizer
Don’t be confused – even though both are used to increase lawn health and growth, they are used at different times and for different purposes. Regular fertilizer can be used throughout the season to provide essential nutrients, while starter fertilizer is only to be used when establishing a new lawn.
There are a few key differences between the two:
- Starter fertilizer has a higher phosphorus ratio and is used before sowing or laying sod.
- Regular fertilizer contains more potassium and nitrogen and is used for established turf when actively growing.
- While regular fertilizer has a longer release period, starter fertilizer has both quick-release and slow-release formulas.
Overseeding
When it comes to overseeding, you can also use a starter fertilizer. The nitrogen will help keep existing grass healthy and green, while the phosphorus will give the new grass seeds an extra boost.
Remember, you’ll have to wait until the third mowing to use weed and feed fertilizer on grass seedlings or newly overseeded lawns. If you don’t, the herbicides will prevent seed germination, and your overseeding efforts won’t pay off.
The best time to overseed is mid-spring for warm-season grasses (March-May) or late summer/early fall for cool-season grasses (late August-September).
FAQ About Fertilizing New Grass
Can you over-fertilize new grass?
You can damage or even kill new grass seedlings if you over-fertilize. So, before you go all out with the fertilizer, stick to the use rate suggested by the manufacturer – no more than necessary. And keep in mind that some states have laws and regulations about what type of fertilizer you can use. Make sure to check the rules for your area!
How much fertilizer do I put on new grass?
When laying out sod or planting new seed, apply 0.5-1 lb of nitrogen for every 1,000 sq. ft. It’s typically a good idea to add equal amounts of nitrogen and phosphorus for seeding projects. But, if you’re sodding, you want to include slightly more phosphorus.
What is the best time of year to fertilize new grass?
New grass needs a starter fertilizer boost right before or shortly after planting, so when to apply starter fertilizer is determined by what type of grass you’re planting.
Fall is the time for cool-season grasses like Kentucky bluegrass or fescues, while warm-season grasses like Bermuda or Zoysia should be planted in late spring or early summer.
How often should I fertilize new grass?
Once you’ve added starter fertilizer to the soil before planting, wait at least six weeks before applying any more fertilizer. This gives your new grass plenty of time to get settled and build a strong foundation for growth. If the soil’s not in its best shape, opt for compost or manure-based compost instead of chemicals.
Final Thoughts
A lush, green lawn doesn’t happen on its own. To get it just right, you’ve got to fertilize your grass properly. With the right starter fertilizer and a bit of know-how, you can establish a beautiful lawn that’ll last for years to come. But if you’re not sure how to do it right, don’t hesitate to reach out to a local lawn care pro. They have the experience you need to get the lawn of your dreams!
Main Photo Credit: Elena Photo / Canva Pro / License (with added text overlay)
Luminita Toma
Luminita Toma is a nature-loving writer who simply adores pretty flowers and lawns. After plenty of research and writing on lawn care and gardening, she's got a keen eye for plants and their maintenance. When she's got some spare time, there's nothing she enjoys more than chilling with her friends, hitting the theatre, or traveling.
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