Weed And Feed On New Grass Seed

How to take care of a lawn after you've put down the seed. One look at your local garden center’s fertilizer aisle and you’re inundated with choices. We’ve taken the mystery out of starter fertilizers for you. If you take care to prepare your lawn and buy the right type of seed for your home, growing a healthy lawn from seed is easy when following these 4 steps.

Care and Maintenance of a Lawn after Seeding

Care after lawn renovation, for at least the first two months, is important for successful seeding. Changing weather patterns in Maryland including warmer than normal temperatures in late summer and fall, fluctuating periods of very wet, and then very dry weather are making seeding more challenging even during the recommended time for lawn projects. Seeding in the fall and then again in the spring may be necessary for a thicker lawn if all of the seed did not germinate and grow with your first attempt.


    is critical to successful lawn establishment. Once wet and seed germination has begun do not let the seed dry out. Postpone reseeding an area during a drought if irrigation cannot be provided.
  • A newly seeded lawn requires daily watering during dry periods.
  • When conditions are windy and dry, the planted area may require several light waterings a day. Pay special attention to soil moisture on hot, windy days, when humidity is low.
  • Sandy soils dry out quickly and require more frequent irrigation. Watering with a light mist is best. The idea is to keep the top layer of soil moist but not saturated.
  • As seedlings grow and mature, the frequency of watering is decreased, but the duration of watering is increased. The water now needs to be available at the root zone and should penetrate the soil so that the top 4-6 inches of soil is moist.
  • It is best to water earlier in the day so leaf blades do not remain wet overnight.


    is an important part of a lawn maintenance program that is often overlooked. Mowing lawns too short (scalping), or infrequently, causes grass to become susceptible to drought injury, weed infestations (especially crabgrass), and foot traffic injury.
  • Begin to mow the new turf when it reaches a height one-third higher than the normal mowing height (e.g., if a 3-inch height is desired, mow when the turf reaches 4 inches). Typically, under optimum growing conditions, this is four to six weeks after seeding. And when mowing during the season follow the “one-third” rule. Remove only one-third of the vegetation (measure from the soil line to the blade tips) at each mowing. Removing too much of the leaf blade at each cutting stresses the new lawn.
  • Soil should be dry enough so that ruts are not formed by the wheels of the lawnmower.
  • Mower blades should be sharp, so a clean cut is made.
  • Generally, mowing needs to be done on a weekly basis during the growing season.


    applied according to soil test results during the initial seeding period is sufficient for 6-8 weeks. Follow-up applications of fertilizer are made as part of a regular maintenance program. For cool-season turf, if the seeding was done in the fall, fertilizer cannot be applied later than November 15th. For seed sown in spring, do not apply after June 1st. Refer to the University of Maryland Extension home lawn fertilizer schedule.


  • Tilling the seedbed exposes dormant weed seeds to water and light prompting them to start to grow. Competition from weeds is greatest on turf sown in early spring. Hand pull the weeds in small areas.
  • Grass seedlings are sensitive to chemical injury, so broadleaf herbicides should not be applied until the lawn has been mowed at least three or four times. Follow label directions.


  • Young seedlings are easily injured. Newly seeded areas should be restricted from foot traffic for a least a month after the seed has germinated or until the new lawn has been mowed at least a couple of times.

By Debra Ricigliano, Maryland Certified Professional Horticulturist, University of Maryland Extension Home and Garden Information Center (HGIC), 2019. Reviewed and edited by Jon Traunfeld, HGIC Director.
Based on HGIC publication HG 102 Lawn Establishment, Renovation, and Overseeding

9 FAQs About Applying Starter Fertilizer to Your Lawn

Whether you are planting new grass from scratch or repairing bare spots, figuring out a proper fertilizer to get your lawn off to the best start can be daunting. Here are the answers to 9 FAQs about applying starter fertilizer to your lawn.

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One look at your local garden center’s fertilizer aisle and you’re inundated with choices for producing your vibrant lawn. We’ve taken the mystery out of starter fertilizers for you.

Our Top Picks for Starter Fertilizers:

1. What is Starter Fertilizer?

Starter lawn fertilizer is a small quantity of fertilizer nutrients applied near the seed at planting. It helps your grass seedlings and sod roots establish more rapidly in the soil than regular fertilizer, leading to a thick new lawn in a short period.

Starter fertilizers for grass may differ slightly in composition, but they all give the grass seeds and new sod the nutritional boost required for healthy germination and rapid root growth. They will usually contain equal amounts of nitrogen, phosphorus, and potassium. However, some types contain two parts of nitrogen and one part of phosphorus and potassium.

You can choose between slow-release and quick-release formulations, with the latter delivering a quick green-up dose of nitrogen. It can be applied to all-new lawns, or to help bare spots recover from winterkill or other damage.

What is the Difference Between Starter Fertilizer and Regular Fertilizer?

According to David M. Kopec of the University of Arizona Extension, the main difference is the amount of phosphorus in the fertilizer. Starter fertilizers usually contain 20 percent more phosphorus than regular fertilizers.

2. What is a Good Starter Fertilizer for Grass Seed and Sod?

Starter fertilizers for lawns come in different compositions of the primary nutrients nitrogen (N), phosphorus (P-phosphate), and potassium (K-potash), or the three numbers listed on the package (NPK ratio).

The numbers list the percentage of each nutrient contained in the starter fertilizer for grass. For example, an N-P-K ratio of 10-10-10 contains 10 percent each of nitrogen, phosphorus, and potassium.

When it comes to the specific job of each of these primary nutrients in regards to the health of your turf:

  • Nitrogen: Is required for satisfactory growth and green coloration.
  • Phosphorous: Plays an important role in various growth processes including good root development.
  • Potassium: Promotes good disease resistance, tolerance of drought, and winter hardiness in turfgrass.

Some examples of the formulations of common starter fertilizers for lawns are 10-10-10, 20-10-10, and 16-8-8. Penn State Extension notes that analyses of 15-10-10 or 10-6-4 are also acceptable used as starter fertilizers for grass, as they also promote good early growth and grass development.

3. Can you Apply a Starter Fertilizer to Grass Seed and Sod?

“Yes, both seed and sod,” states Peter Landschoot, Ph.D., professor of turfgrass science at Penn State Extension.

Seed: At the seedling stage, “Grasses need greater amounts of nitrogen and phosphorus than mature grass plants because seedlings are producing new tissues rapidly and thus have higher energy and nutrition requirements.” Overseeding a lawn will take more time, but sod will be more expensive.

Sod: “Even though sod is mostly composed of mature turf, many of the roots have been severed during the harvesting operation,” Landschoot says. Some nitrogen and phosphorus (as starter fertilizer) applied to the soil before the sod is laid should help hasten the development of new roots.”

4. Is it Best to Get a Soil Test First to See Phosphorus Levels?

Landschoot notes, “Because soil-test levels of phosphorus don’t change much over short periods, you can collect soil samples and submit them to a test lab to determine phosphorus levels within a year of establishing turf.”

Nearly all extension service offices offer low-cost soil testing services. Check with your local Cooperative Extension Office for details. Soil samples can be collected at any time during the year as long as the soil is not frozen. Ideally, you want to collect soil and submit the sample(s) to a test lab as close to the time of establishment as possible.

Pro Tip: Make sure to leave time to get the test back with the phosphorus and other recommendations. It can take 1-3 days or up to two weeks to get results, depending on the test. You’ll need a few extra days to buy fertilizers and make necessary adjustments to the soil before planting your new lawn.

5. Is There a Standard Amount of Starter Fertilizer I Should Use?

If you didn’t get a soil test to determine how much starter fertilizer to use for your lawn, Landschoot offers these general recommendations:

  • “Starter fertilizers should be applied at 0.5 to 1 lb. nitrogen per 1,000 square feet. Amounts in excess of 1.5 lb. nitrogen per 1,000 square feet can burn the young turf and result in poor establishment.”

Quick-release nitrogen will speed up seedling development.

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Pro Tip: Landschoot notes, “Application of a starter fertilizer is not a substitute for the phosphate and potash recommended on your soil test report.”

6. Are There Circumstances Where you Shouldn’t Use a Starter Fertilizer?

  • You should not use starter fertilizer in areas where you cannot control runoff. Nitrogen and phosphorus from indiscriminate use of fertilizers have caused such great environmental concerns that about half the states in the U.S. have imposed regulations on fertilizer use.
  • Don’t use starter fertilizer if your soil test shows it’s not needed. Instead, apply 1-2 inches of organic fertilizer, such as a biosolids fertilizer or manure-based compost, and work into the soil before establishing your new turf. These amendments contain significant amounts of nitrogen and phosphorus to get your new lawn off to a healthy start.

Pro Tip: It’s common for homeowners to apply lawn fertilizer, depending on where they live, in the spring, but not before the grass greens up.

Once your healthy lawn has been established, fertilize every six to eight weeks. The best time is late spring for warm-season grasses (e.g., centipedegrass, St. Augustinegrass, and Zoysiagrass) and fall for cool-season grasses (e.g., Kentucky bluegrass and tall and fine fescues).

Follow good lawn care maintenance such as aeration and mowing heights to keep your lawn healthy and beautiful.

7. When Should you Apply Starter Fertilizer?

Apply starter fertilizer before seeding or laying sod, or after you plant the new grass seed. You don’t want to apply it directly to newly planted sod or burning can occur.

Note: Wait six to eight weeks before applying another dose of balanced fertilizer to your grass after planting so it doesn’t burn the grass.

When it comes to knowing how much starter fertilizer for the grass, you’ll need a soil test. The three most important nutrients required for good growth and health of your turfgrass are nitrogen, phosphorus, and potassium, which a starter fertilizer contains.

It’s best to till the fertilizer 4 to 6 inches into the soil along with any additional amendments you are adding. You can also spread it over the site immediately after planting your new grass seed.

Pro Tip: When phosphorus and potassium are applied only to the surface of the soil they cannot move down into the soil fast enough and nitrogen can easily be leached out before the grass even Has a chance to uptake its nutrients.

8. Can I Use a Starter Fertilizer for Grass That is Established?

Probably not. Although you can use a starter fertilizer for a lawn that is established, it’s better to use a well-balanced fertilizer designed specifically for grass that is established.

Starter fertilizer might not contain all the required nutrients for continued growth and good health. It won’t hurt the grass but might lack the needed nutrients that a well-balanced fertilizer for continued lawn maintenance contains.

9. How do you Apply Starter Fertilizer?

If you’re planting sod, apply a fertilizer before you put down the sod. If you’re planting seed, apply a fertilizer either before or after planting the seed.

  • If you apply starter fertilizer before planting grass seed or sod:

Pour the required amount into a standard fertilizer spreader and evenly apply the starter fertilizer over the planting site. Once applied, work the product 4 to 6 inches into the soil.

  • If you apply starter fertilizer after you’ve planted grass seed:

Use the fertilizer spreader and apply it over the soil. Then water in the fertilizer.

There are different types of fertilizer applications. You can choose between liquid or granular. Both supply the essential nutrients; however, Michigan State University recommends liquid application.

Granular fertilizers can be inconsistent in spreading and can be “hot,” burning young plants that are nearby. Follow directions on your chosen fertilizer to verify the best application process.

Pro Tip: If you’re overseeding or using sod, avoid weed and feed fertilizers for four weeks or until your third mowing. The herbicides may prevent root development in your new grass seeds.

Wait Time: On average, grass seed takes about 10 to 14 days to germinate, but it can take up to 30 days.

Phosphorus and its Role in a New Lawn

When it comes to explaining phosphorus and its role, Landschoot notes, ”Phosphorus is included in starter fertilizer primarily to enhance root development. Some research shows little influence of phosphorus on turf establishment in soils containing adequate to high levels of soil-test phosphorus; whereas other studies show benefits even when phosphorus levels are adequate.

Generally, developing seedlings growing in compact soils during cold temperatures are thought to benefit more from phosphorus in starter fertilizer.

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Nitrogen, Organic Matter, and a New Lawn

If your lawn is not rich in natural organic matter, nitrogen plays an important role. Landschoot notes, “In cases where soils are not amended with compost, nitrogen is almost always needed for rapid establishment.

Our research shows a greater influence of nitrogen compared to phosphorus on the rate of turf establishment, so if you can’t use phosphorus (or you think there is enough phosphorus in the soil), an application of 1 lb. quick-release nitrogen per 1,000 square feet will speed up seedling development.”

Hire a Professional

If you’re a homeowner that isn‘t down to DIY or you’re frustrated with the progress of your garden oasis, you can hire a lawn care professional to get your dream lawn started while you relax.

Main image credit: Jay Crihfield / Adobe Stock

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Joyce Starr

Joyce Starr has been writing on horticultural and landscaping topics for over 15 years. In addition, for the past 20 years she’s owned and operated a landscaping and design business. She shares her experience and passion for all things green through her writing.

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4 Steps to Getting New Grass Seed Growing Strong

Plenty of websites you come across will say that starting new grass seed is a task best left to professionals. We think a bit differently. Truth be told, if you take the time and effort to prepare your lawn correctly, and are diligent about maintaining your lawn conditions, you can save plenty of money by starting a new, thicker lawn from seed. Our Lawn and Garden Center associates are here to help you make sure you choose the right grass seed type for the season, take consideration for the amount of light available and other ground conditions like foot traffic or pets. So let’s get started.

1. Preparing your lawn for sowing grass seed

Before planting, prepare the area of your yard that you plan on seeding. Pick up and move any solid objects, leaves, branches then clear away any dead grass and weeds. Weeds need to be pulled out cleanly with all roots. Do not apply any type of pre-emergent or post-emergent weed killer to the area you plan to seed.

Tilling or heavy raking will loosen the top layer of soil. Add a special type of fertilizer designed for seeding, then till or rake a second time to mix the soil and fertilizer.

2. Sowing grass seed correctly

Use a broadcast spreader to evenly distribute the grass seed around your yard. To shield the new seed from birds that will want to eat it, cover this newly seeded area with straw. It’s also a good idea to put a tape line or some rope around the area to prevent anyone from stepping on the soil. During the initial grow cycle, it’s important to keep this area clear of any debris that has fallen from trees or blown in from other areas of the yard.

3. Correctly watering new grass seed

If you want your new grass seed to grow as healthy as possible, your soil should be kept moist at all times. This is what makes germination possible, so make sure your soil is damp well below the surface. Anywhere from three to four inches of the soil should be damp, but not mud.

It’s important that the soil is watered when necessary, but that water doesn’t puddle on the surface. In most climates, you’ll need to water daily, but dry climates will demand more. This new watering schedule should continue until new grass is seen growing.

4. The right time to add fertilizer to your new grass seed

If your grass was seeded and watered properly, it should germinate and begin to grow in about 14 days. It’s important that you avoid applying heavy fertilizers until the grass is established and thick. You should also avoid using pre-emergent and post-emergent weed killers and herbicides because new grass is extremely susceptible to damage from harsh chemicals. Only use special seeding cycle weed killer, or just pull any weed growth out by hand until the grass is established.