Creating a green expanse of grass is often a difficult process. Grass seed and sod both use large amounts of nutrients, so the quality of the soil is important. Even if you have the best soil in the world, it doesn’t have enough nutrients to support turf grass; this is especially true when starting from scratch and working with seed or sod. Knowing which kind of fertilizer to use can make all the difference!
:max_bytes(150000):strip_icc():format(webp)/GettyImages-1135338910-ae2873c25a69405f9e12863c9b34f33a.jpg)
Why Fertilize?
Turf grasses need high amounts of nutrients, especially nitrogen and phosphorous, to support strong growth. In order for lawns to grow well, they need soil with high levels of nitrogen and phosphorous. That’s why new lawns are often started in soils that are compacted, damaged and low in nutrient content.
If you sow seed or sod in soil lacking primary nutrients, you are likely to end up with a patchy lawn vulnerable to invading weeds and insects. Erosion can add to your woes. It is important to start out with the best possible result in a new lawn, which can mitigate these problems and help your turf stand up to mowing and normal wear and tear. Regardless of where you plan to create a lawn, it is essential to apply fertilizer at the right time for good results.
One way to ensure your lawn is healthy and resistant to disease is to have a soil test. Since fertilizers are made up of variable amounts of nutrients, knowing what your lawn lacks can help you choose the best product for it. Depending on which state you live in, you may be required to have one before applying phosphorous, as this has been determined to contribute to algal blooms in local estuaries.
Tip: Grass fertilizers are labeled with an NPK ratio, which gives the percentages of nitrogen, phosphorous and potassium that make up the product. Nitrogen is essential for grass to grow in dark green color. Phosphorous supports root development. Potassium helps prevent disease and gives some winter protection.
What Is Starter Fertilizer?
Starter fertilizers are usually labeled “starter.” They also might be labeled “turf builder.” Starter fertilizers have higher amounts of nutrients than most lawn fertilizer and may feature a quick-release nitrogen to encourage rapid growth.
Fertilizer formulas contain balanced blends of nitrogen, phosphorous and potassium. NPK 10-10-10 is a balanced blend that contains 6 percent nitrogen, 5 percent phosphorus, and 1 percent potassium. A 20-10-10 blend contains 20 percent nitrogen and 10 percent phosphorus, while a 5-10-5 formula has only 5 percent nitrogen, 5 percent phosphorus and 1 percent potassium. If you start with sod, choose a fertilizer with a higher percentage of nutrients such as a 16-16-16 formula.
When applying fertilizer, you should use the formula recommended for your soil condition. A soil test can help you determine how much fertilizer to use.
How to Use Starter Fertilizer
To treat a new lawn, choose a granular type starter. Premixed ready-to-spray products are available and convenient for treating problem spots. These products are not cost effective for large expanses, though.
Adding starter fertilizer to the soil before planting can help plants grow more quickly. It also releases nutrients more quickly and makes them immediately available to the seed or sod. This method also allows you to avoid burning new sod by not tilling it in, and avoids the potential for damaging delicate roots of sprouting seed or sod.
After you plant your seeds, water them thoroughly. This method is more convenient than watering all at once once you’ve planted the seeds. It saves time by eliminating a few extra steps.
Tip: Do not use “weed and feed” type fertilizers with grass seed or sod. Herbicides that prevent germination can slow the growth of a strong root system, which can lead to unhealthy lawns. Wait at least three to four months until the lawn is well established before using these types of fertilizers.
When to Feed a New Lawn
When you are seeding a new lawn, it is important to apply a second application of starter fertilizer. Once the seed has germinated or if you’ve chosen sod, you can test by grasping a handful of the sodded grass and giving it a gentle tug. If it remains in place and doesn’t pull up this mean roots are establishing. The nutrient needs differ slightly for a newly seeded lawn versus a sodded lawn after the grass is up and growing.
Fertilizing a Newly Seeded Lawn
After sowing seed, it may take anywhere from four to eight weeks before the new lawn is ready for another feeding, assuming the climate and variety of turf grass are suitable. Nitrogen is the most commonly used element at this stage, so choose a fertilizer with a greater amount of nitrogen for the NPK ratio. An example of a good choice might be 24-25-4.
Fertilizing a Newly Sodded Lawn
A newly sodded lawn will require a starter fertilizer such as a 16-16-16 applied at planting time. The amount of fertilizer needed depends on the variety and climate of your lawn, which can be established by how much fertilizer you initially apply at planting time.
When to Use Regular Fertilizer
After two applications of starter, provided the lawn has established, you can begin to feed it with regular fertilizer according to your climate and grass type. How often to fertilize depends on how much time you want to spend maintaining your lawn. Some people prefer to feed their lawns every three months; others suggest that once a year is sufficient.
Tip: Overfertilizing lawns can cause a brown or yellowing of the grass due to an excess of nitrogen. This is because superphosphate and urea are used during lawn fertilization, which are both phosphorus-rich compounds. Both can cause the lawn’s roots to overgrow and die, resulting in patchy dead spots or yellowing tips.