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When to Fertilize New Grass: A Guide for Gardeners



by Bryan Mckenzie


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Creating a lush green lawn from scratch is a delightful experience for any gardener. But, achieving that perfect lawn requires an investment of time, patience, and effort. One of the most crucial factors that determine the success of lawn establishment is fertilization. The right fertilizer applied at the right time can make a world of difference in the health and appearance of your new grass.

However, using the wrong type or applying an excessive amount of fertilizer can lead to unwanted consequences such as stunted growth or environmental damage. In this guide, we will walk you through every aspect of fertilizing new grass, including when to fertilize, which type of fertilizer to use, how to apply, and additional tips for achieving that thick, green lawn you’ve always dreamed of.

The Importance of Fertilizing New Grass

Fertilizing new grass is crucial for the healthy establishment of a lawn. A properly fertilized lawn develops strong roots, has vibrant green color, and is better able to withstand stressors such as drought, pest infestations, and foot traffic. Nitrogenphosphorus, and potassium are the primary macronutrients that grass needs for healthy growth. Nitrogen aids in the formation of lush, green blades, while phosphorus promotes root development and flower production. Potassium helps grass resist disease and stress.

Applying the appropriate fertilizer at the right time not only encourages healthy growth and development of your new grass but also helps protect the environment by reducing runoff and minimizing the need for pesticides. While the benefits of fertilizing new grass are many, it is important to be mindful of the risks of over-fertilizing, which we will discuss in the next section.

Why You Should Fertilize New Grass

  • Fertilizing new grass helps to establish a healthy root system in your lawn, leading to improved drought tolerance, pest resistance, and overall vigor.
  • Applying the right amount of fertilizer at the appropriate time encourages rapid growth and the development of a thick, lush lawn.
  • Fertilizer provides the essential macronutrients that grass needs, such as nitrogen, phosphorus, and potassium, to promote vigorous growth, bright green color, and strong roots.
  • Fertilizing new grass can prevent soil nutrient depletion and deficiencies that can inhibit healthy growth and development.
  • Using fertilizer can reduce the amount of water needed to maintain your lawn, as proper fertilization can improve the water-holding capacity of the soil.
  • A well-fertilized lawn helps to minimize weed invasion by creating thick, healthy turf that is less susceptible to weed infestations.
  • Fertilizing new grass can also help reduce soil erosion, improve soil structure, and minimize erosion runoff.
  • Fertilizing new grass is essential to establish a healthy, resilient lawn that can withstand diverse stressors while minimizing environmental impacts.

The Risks of Over-Fertilizing

Risks of Over-Fertilizing

Over-fertilizing new grass can have unintended consequences that can be detrimental to the health of your lawn, the environment, and your wallet. Here are some risks to consider before applying fertilizer:

  • Burning of Grass: Applying excessive amounts of fertilizer or fertilizing during high temperatures can cause nitrogen burn. Nitrogen burn is a condition where the tips of grass blades turn brown and dry out. If left untreated, it can kill the grass.
  • Water Contamination: Over-fertilizing can cause nutrients to leach into the soil, leading to the contamination of groundwater and waterways. Algae blooms and fish kills are common symptoms of over-fertilized water.
  • Fungal Infections: Over-fertilized turf is more susceptible to fungal diseases such as brown spots, rust, and dollar spot. These diseases can be difficult and costly to treat.
  • Uneven Growth: Applying too much fertilizer in one area can cause uneven growth. Thick, lush patches of grass can develop in some areas, while other areas remain patchy and thin.

To avoid these risks, it is essential to follow the recommended guidelines for fertilizing new grass, such as proper timing and appropriate amounts.

Over-fertilizing may seem like a quick way to achieve a beautiful lawn, but it can lead to long-term problems. Remember to always read the label, use the recommended amount, and follow good lawn care practices to ensure optimal results for your new grass.

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When to Fertilize New Grass

Timing is key when it comes to fertilizing new grass. Fertilizing at the right time ensures that the grass receives the necessary nutrients to establish strong roots and achieve healthy growth. The best time to fertilize new grass is during the growing season when the grass is actively growing and using nutrients.

For cool-season grasses, such as Kentucky bluegrass and fescue, the ideal time to fertilize is in early spring and early fall. For warm-season grasses, such as Bermuda grass and Zoysia grass, late spring and summer are the optimal times for fertilization.

The specific timing may vary depending on your location, climate, and grass variety. Factors such as the age of the lawn, soil fertility, and amount of rainfall should also be considered. Applying fertilizer when the grass is not actively growing can lead to wasted nutrients and environmental pollution. We will discuss more factors to consider in the next section.

Timing is Key

Timing is key when it comes to fertilizing new grass. The optimal time to fertilize your lawn depends on several factors including the climategrass type, and time of year. In general, it is best to fertilize new grass when the roots are actively growing but before the blades start to grow excessively.

This typically occurs when the grass has been mowed twice; however, you should not fertilize the new grass until it has been established for at least four weeks. During the establishment period, it’s crucial to ensure that the grass has enough water and oxygen levels to promote strong root growth.

Nitrogen is required in larger amounts during the spring and fall, and less in the summer and winter months. It is important to follow manufacturer instructions to avoid over-fertilizing, which can cause damage to the environment and burn your grass, resulting in patches of dead turf. Consider the weather conditions before fertilizing. Avoid applying fertilizer when temperatures exceed 85°F as it can burn the grass. Instead, apply it during cooler times of the day or wait for a cooler day to fertilize.

Also, avoid fertilizing new grass during a drought or overly wet conditions as this can lead to leaching and runoff. Finally, it is recommended that you fertilize your lawn a total of three to four times per year with a balanced fertilizer, which will keep your lawn healthy and lush throughout the growing season.

Factors to Consider

When deciding when to fertilize new grass, there are several key factors that you should consider. The first factor to consider is the climate of your region. Grass growing in a cooler climate may have a different fertilization requirement than grass growing in a warmer climate. Another important factor is the type of grass you are growing. Different grass varieties have different nutrient requirements and may need specific types of fertilizers.

The soil type and pH levels should also be considered, as fertilizers can react differently depending on the soil composition. Finally, it is important to consider the age of the grass. New grass should be fertilized sparingly, while established lawns may require more frequent fertilization.

By taking into account these factors, you can determine the appropriate timing and frequency of fertilizer application for your new grass. It is important to note that over-fertilizing grass can result in a nutrient burn or environmental damage, so always follow the recommended application rates and guidelines for your specific fertilizer.

Types of Fertilizers for New Grass

Types of Fertilizers for New Grass

Choosing the right type of fertilizer for your new grass is crucial for the success of your lawn establishment. There are several types of fertilizers available on the market, including nitrogen fertilizersphosphorus fertilizerspotassium fertilizers, and organic fertilizers. Nitrogen fertilizers are the most commonly used and help promote leaf and stem growth, resulting in a lush green lawn.

Phosphorus fertilizers are essential for root development, seedling growth, and stress tolerance. Potassium fertilizers are important for improving disease resistance and drought tolerance. Organic fertilizers are made from natural ingredients and provide a slow release of nutrients over time, contributing to soil health and reducing the risk of over-fertilization.

Depending on your soil composition and grass type, you may need to use a specific type or combination of fertilizers. We will discuss the factors to consider when selecting fertilizers in the next section to help you make an informed decision.

Nitrogen Fertilizers

Nitrogen fertilizers are the most commonly used type of fertilizer for new grass, as they promote leafy growth and give the grass its distinctive green color. Nitrogen is an essential macronutrient for plant growth and development, as it is a component of chlorophyll, the pigment that gives plants their green color and is responsible for photosynthesis. Three types of nitrogen fertilizers are typically used on new grass: quick-release, slow-release, and controlled-release.

  • Quick-release nitrogen fertilizers are designed to rapidly release nitrogen into the grass, which leads to fast growth and greening. They are often used in the spring to kick-start growth after winter dormancy. However, because they release nitrogen quickly, there is a higher risk of over-fertilizing and burning the grass if not applied properly.
  • Slow-release nitrogen fertilizers gradually release nitrogen over a longer period, usually up to 10-12 weeks. They provide a steady supply of nutrients over time, which promotes even growth and reduces the risk of burning the grass. However, slow-release fertilizers tend to be more expensive than quick-release fertilizers.
  • Controlled-release nitrogen fertilizers are designed to feed the grass over a predetermined period, often up to 5-6 months. They typically consist of coated granules that release nitrogen in response to temperature, moisture, or microbial activity. Controlled-release fertilizers are ideal for those who want to minimize the number of fertilizer applications needed throughout the season.

When choosing a nitrogen fertilizer, consider the specific needs of your lawn and the timing of the application. Always follow the manufacturer’s instructions carefully, and avoid over-fertilizing, as this can lead to nitrogen runoff into waterways and environmental damage.

Phosphorus Fertilizers

Phosphorus is an essential nutrient for the development of strong, healthy roots. Phosphorus fertilizers are typically recommended for use during the establishment phase of new grass. When selecting a phosphorus fertilizer, look for one with a high middle number on the fertilizer bag label. This indicates that the fertilizer has a high percentage of phosphorus relative to nitrogen and potassium.

Examples of phosphorus fertilizers include superphosphate, triple superphosphate, and bone meal. Superphosphate is a type of phosphorus fertilizer that is made by treating rock phosphate with sulfuric acid. This treatment converts the rock phosphate into a form that is more readily absorbed by plants. Superphosphate typically contains between 16-20% phosphorus and is fast-acting, making it an ideal choice for establishing new grass.

Triple superphosphate is a concentrated form of phosphorus fertilizer that contains three times the amount of available phosphorus as regular superphosphate. The phosphorus in triple superphosphate is more gradually available, making it a better choice for use in established lawns. Bone meal is another organic phosphorus fertilizer that is made from ground animal bones. It is slow-release and is typically recommended for use in the fall or early spring.

Keep in mind that while phosphorus is beneficial for new grass, excessive use of phosphorus can pollute nearby waterways and harm aquatic life. Be sure to follow the recommended application rates and do not apply phosphorus fertilizers if a soil test indicates that the soil already contains adequate levels of phosphorus.

Potassium Fertilizers

Potassium is a vital nutrient for grass because it helps it withstand drought, cold temperatures, and disease. Potassium is an essential part of the cellular fluid, which helps to regulate water flow in plants. When grass receives enough potassium, it is more resilient, which makes it less likely to suffer from environmental stress factors. Applying a potassium-rich fertilizer helps new grass build strong roots and develop thick, healthy blades. Here are some common types of potassium fertilizers used for new grass:

  • Muriate of Potash (MOP) – a readily available, inexpensive fertilizer with a high concentration of potassium chloride that tends to be more soluble in water.
  • Sulfate of Potash (SOP) – contains a high concentration of potassium sulfate and is also a good source of sulfur, which some soils may lack. SOP is less soluble than MOP.
  • Langbeinite – a natural rock mineral containing potassium, magnesium, and sulfate. It has a slow-release form of potassium and is better for maintaining an established lawn.

When choosing a potassium fertilizer, it’s important to consider the nutrient ratio of your soil. A soil test can help determine how much potassium is already present in the soil and how much you need to add. Too much potassium can also harm the grass and increased soil salinity, so follow the manufacturer’s application recommendations carefully. Potassium fertilizers are an essential component of new grass establishment, helping the grass become more resilient, healthy, and green.

Organic Fertilizers

Organic fertilizers are derived from natural materials and are an environmentally friendly option for fertilizing new grass. These fertilizers contain a range of beneficial nutrients, such as nitrogen, phosphorus, potassium, calcium, and magnesium, that are slowly released over time to nourish your lawn. Here are a few types of organic fertilizers that you can use to promote the healthy growth of new grass:

  • Compost: This organic fertilizer is made from decomposed plant matter and provides a balanced mix of nutrients. Spread compost evenly over the soil before seeding or laying sod.
  • Bone meal: This fertilizer is high in phosphorus, which promotes root growth. It is best applied before laying sod or planting seedlings directly into the soil.
  • Blood meal: This fast-acting fertilizer is high in nitrogen and is best used to promote healthy green growth. It should be applied sparingly to avoid burning your new grass.
  • Fish emulsion: This liquid fertilizer provides a quick boost of nitrogen and other nutrients and is easy to apply. Be sure to follow the instructions carefully, as too much fish emulsion can harm your new grass.

Organic fertilizers are not only beneficial for your lawn but also for the environment. They are non-toxic and biodegradable, and reduce the risk of pollution from synthetic fertilizers. However, organic fertilizers tend to be more expensive and their nutrient content is often lower than synthetic fertilizers, which means you may need to apply them more frequently.

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How to Fertilize New Grass

Fertilizing new grass may seem like a daunting task, but the good news is that it can be done with minimal equipment and experience. Before applying fertilizer, it is important to test the soil pH to determine the exact nutrient requirements of your lawn.

Once you know the amount of fertilizer your lawn needs, you can proceed with applying it. There are two primary methods of applying fertilizer: spreading by hand or using a fertilizer spreader. Spreading by hand is best for small lawns or hard-to-reach areas, while a spreader is more efficient for larger areas.

After application, the fertilizer should be watered in a well to prevent burning and to help the nutrients penetrate the soil. In addition to the step-by-step guide, we also recommend some recommended products. Always be sure to read and follow the manufacturer’s instructions for the proper application and handling of the fertilizer product.

Step-by-Step Guide

Applying fertilizer to new grass requires precision and care. Follow these simple steps to ensure that your grass gets the nutrients it needs without causing damage to the environment or risking over-fertilization:

  1. First, determine the square footage of your lawn to calculate the amount of fertilizer you need.
  2. Select the appropriate spreader for your chosen fertilizer.
  3. Read the instructions on the fertilizer package carefully and measure out the appropriate amount of fertilizer.
  4. Divide the fertilizer into halves or quarters and apply it in a criss-cross pattern to achieve even coverage. Avoid spreading fertilizer too close to sidewalks, driveways, or water sources.
  5. Water your lawn immediately after fertilizing to activate the fertilizer and prevent any burn spots. Watering with about 1/2 inch of water is recommended.
  6. Wait 6-8 weeks to fertilize again, depending on the type of fertilizer you used and the condition of your lawn.
  7. Repeat these steps to give your new grass the best chance to thrive and create a beautiful, healthy, and sustainable lawn.

Following these simple steps ensures that your new lawn gets the right amount of nutrients without causing any damage to the environment. Remember always to read the instructions on the fertilizer package to avoid over-fertilization which can harm your lawn and the environment.

starter fertilizers help started right

When selecting a fertilizer for your new grass, there are many products on the market that can be helpful. Here are some recommended products for fertilizing new grass:

  • Scotts Turf Builder Starter Food for New Grass: This fertilizer has a formulation designed specifically for newly seeded lawns and helps grass grow up to 70% thicker and 35% more quickly. It also contains a quick-release form of nitrogen for immediate green-up.
  • Pennington Ultragreen Starter Lawn Fertilizer: This fertilizer contains 22% nitrogen, 4% phosphorus, and 12% potassium, which is ideal for the early stages of lawn growth. It promotes fast root establishment and maintains a deep, green color of the grass.
  • BioAdvanced 2-in-1 Moss and Algae Killer and Lawn Fertilizer: This product not only fertilizes but also eliminates moss and algae growth in lawns, making it an excellent choice for homeowners with these issues. It provides nutrients for up to three months and promotes a vibrant, healthy lawn.

These fertilizers can be applied during the early stages of grass growth to promote healthy development. It is important to follow the application instructions on each product carefully and avoid over-fertilizing to prevent damage to your lawn. Remember that a healthy lawn is not just determined by the use of fertilizers, but also by proper watering, mowing, and maintenance practices.

Additional Tips for Fertilizing New Grass

To ensure that your newly established lawn thrives, there are some additional tips to keep in mind when fertilizing. After applying fertilizer, it is crucial to water thoroughly to help the nutrients penetrate into the soil.

Avoid watering too much or too little, as both can lead to problems with your lawn. It’s also important to wait a few days after fertilizing before mowing your new grass. Mowing too soon can cause the fertilizer to be unevenly distributed and may even damage the new grass.

Additionally, it is essential to be mindful of your local climate and weather conditions when deciding when to fertilize. Hot, dry weather may require more frequent watering to prevent the grass from drying out, while cooler weather may require less frequent watering. By following these additional tips, you can help ensure that your new lawn grows beautifully and remains healthy for years to come.

Watering After Fertilizing

Watering your lawn immediately after fertilizing helps to activate the nutrients and drive them deep into the soil where the roots can absorb them. Failure to water after fertilizing can result in the nutrients becoming locked in the surface of the soil where they are less accessible to the grass and therefore less effective. Here are some key points to remember when watering your lawn after fertilizing:

  • Water your lawn as soon as possible to help dissolve and activate the fertilizer.
  • Make sure to water the fertilizer evenly over the entire lawn to prevent spotting or other issues.
  • Water for a long time but less frequently to allow the nutrients to deeply penetrate into the soil.
  • Avoid overwatering, which can lead to nutrient runoff and waste.
  • Consider using a sprinkler system or hose with an adjustable nozzle to ensure even coverage.

It’s important to note that watering immediately after fertilizing is necessary, but be sure not to overdo it. Frequent and heavy watering can cause the nutrients to leach out of the soil faster, which results in less effective fertilization. A general rule of thumb is to water your lawn for about 30 minutes per session, but be sure to check your specific fertilizer’s instructions for watering and follow them carefully. Taking care to properly water your lawn after fertilization will ensure you get the most desirable results from your fertilizing efforts.

Mowing After Fertilizing

Mowing after fertilizing is an important step in maintaining a healthy, beautiful lawn. Here are some tips to keep in mind:

  • Wait to mow at least two days after fertilizing. This allows the granules to absorb into the soil and prevents them from sticking to the mower blades.
  • Set your mower height to about 3 inches. This encourages deeper root growth and shades the soil to reduce evaporation and weed growth.
  • Leave grass clippings on the lawn as they decompose, they provide valuable nutrients back into the soil.
  • Alternate mowing directions every time you mow. This ensures even cutting and prevents grass from developing a grain that can lead to stress.
  • Keep mower blades sharp to prevent tearing the grass, which can leave it vulnerable to disease and pests.

Mowing too soon after fertilizing can cause the granules to become dislodged and prevent proper absorption into the soil. Additionally, mowing too low can stress the grass and prevent healthy growth. It is essential to follow these guidelines to ensure the proper care and maintenance of your lawn after fertilization.

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In conclusion, fertilizing new grass is an essential component of lawn establishment. Through proper fertilization, you can give your new lawn the best possible start and encourage healthy growth and development for years to come.

Remember to consider the timing and type of fertilizer you use, as well as how to apply it correctly to avoid over-fertilization. It is recommended that you follow the manufacturer’s dosage recommendation and remember that more fertilizer is not always better. While synthetic fertilizers can provide quick and dramatic results, organic fertilizers offer a more natural and sustainable approach to maintaining a healthy lawn.

Additionally, it is crucial to water your lawn adequately after fertilization and plan on mowing your grass several times after fertilizing to avoid burning the blades. By taking these steps, you can create a beautiful, healthy lawn that you and your family can enjoy for years to come.

Frequently Asked Questions

1. Should I fertilize new grass?

Yes, fertilizing new grass is important for the healthy establishment of your lawn. However, it is essential to apply the right amount of fertilizer at the right time to avoid over-fertilizing and causing harm to the grass or the environment.

2. How soon can I fertilize my new grass?

It’s best to wait until your new grass has been established for 6 to 8 weeks before fertilizing for the first time. This allows the roots to take hold and minimizes the risk of fertilizer burn or damage to the tender young plants.

3. What is the risk of over-fertilizing new grass?

Over-fertilizing new grass can result in the excessive growth of foliage at the expense of root development, leading to shallow root systems that are more susceptible to disease, drought, and other stressors. Over-fertilizing can also leach nutrients into groundwater, leading to pollution and environmental damage.

4. Can I fertilize new grass too late in the season?

Yes, fertilizing too late in the season can stimulate lush blade growth that is susceptible to frost damage. Fertilizing in the fall can also increase the risk of winter damage by delaying the hardening of the turf.

5. Can I use any type of fertilizer on new grass?

No, different types of grass require different nutrient ratios, and using the wrong type of fertilizer can lead to imbalance and harm the grass. It’s best to choose a fertilizer tailored to your specific grass type and follow the instructions for application.

6. How often should I fertilize new grass?

The frequency of fertilization depends on the grass type and environmental conditions. As a general guideline, cool-season grass such as Kentucky bluegrass should be fertilized 2 to 4 times a year, while warm-season grass such as Bermuda grass may need up to 6 applications per year. Always read the instructions carefully and avoid over-fertilization.

7. What is the best time of day to fertilize new grass?

It’s best to fertilize early in the morning when the grass is dry and the temperatures are cooler. This gives the fertilizer time to settle onto the blades and be absorbed before the heat of the day. Avoid fertilizing in the midday heat or when the grass is wet with dew or rain.

8. Can I fertilize my new grass with natural or organic fertilizers?

Yes, natural or organic fertilizers can be a good choice for fertilizing new grass. They release nutrients more slowly, reducing the risk of over-fertilization, and improve soil health over time. However, they may not provide the precise nutrient balance needed by different grass types and may require more frequent applications.

9. Can fertilizing new grass prevent weed growth?

Yes, properly fertilized grass is thicker and healthier, which can help prevent weed growth by crowding out potential invaders. However, using a pre-emergent weed control product in the spring before the weed seeds germinate can be even more effective in preventing weed growth.

10. Should I apply fertilizer before or after mowing?

It’s best to fertilize after mowing when the grass blades are shorter. This allows the fertilizer to reach the soil more easily and minimizes the risk of fertilizer burn on the blades. Wait at least 24 hours after fertilizing before mowing again to allow the fertilizer to be fully absorbed.


Bryan Mckenzie
Hi there — my name is Bryan McKenzie. Before I’d got into gardening, I worked as a landscape designer at landscape design and consultation company in Jacksonville. I enjoy sharing the vast gardening experience I’ve accumulated throughout the years with like-minded green thumbs. Read more about me and my wife.
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