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The Complete Guide to Using Lawn Fertilizer

One of the most common questions homeowners ask during the summer is “Exactly how much fertilizer should I apply to my lawn?”

Lawn with heavy foot traffic will need more fertilizer than one without — often twice as much. Also, different types of grass prefer different types of fertilizer. Many types are also better adapted to hot summers and can tolerate higher levels of fertilizer.

I know that buying lawn fertilizer can seem intimidating because of all the different types and price ranges. You may feel overwhelmed by the information like many people, which makes you feel tempted to take the easy road.

I created this guide to help you take control and learn about fertilizers for your lawn.

What are the benefits of fertilizing lawns?

Lawn fertilizer

Fertilizing a lawn offers many benefits. Here are some of them:

Healthier grass

Fertilizer provides essential nutrients that help improve the health of your grass. This leads to better water retention, which leads to healthier roots. This results in stronger, thicker blades that are less likely to become damaged by pests or disease. It also helps prevent brown spots from forming on the lawn.

Improved growth rate

Lawns are green because of the chlorophyll in the leaves. Chlorophyll needs sunlight to produce energy for plants through photosynthesis. Fertilizers increase chlorophyll production, which increases photosynthesis and growth. This means you’ll see more green as well as thicker, fuller grass blades with fewer bare or brown spots.

Thicker roots

When a plant is healthy, it has strong roots that grow deep into the soil so it can get water and nutrients when they need them most. This also helps to protect against certain root problems such as drought conditions and soil compaction. Phosphorus-rich fertilizer helps to spread a new collection of dense underground roots and strengthen the existing roots above the ground.

What is the best lawn fertilizer?

The best lawn fertilizer for your grass depends on your location, climate, and soil. There are two types of lawn fertilizers: organic, and inorganic.

Organic Lawn Fertilizer

Organic lawn fertilizer is made from natural materials such as compost, or manure. It releases nutrients over time as it breaks down.

Organic fertilizers work well in areas where the soil has been depleted of nutrients or where water runoff is a problem because they don’t leach away quickly as synthetic fertilizers do.

Lawn fertilizer

I’ve been using organic fertilizers for a long time. They are much more expensive, but also much less toxic to the environment. I also like to use them because they are made from natural sources and break down into natural elements after a few months.

This means you can use them on your lawn without fear of polluting groundwater or leaching into the soil as some inorganic fertilizers do.

However, organic fertilizers aren’t always easy to find at local garden centers; you may have to go online to order them or find them at farm supply stores.

Inorganic Lawn Fertilizer

Lawn fertilizer

Inorganic fertilizers are synthetic compounds that contain only nitrogen (N), phosphorus (P), and potassium (K) — these are known as NPK fertilizers — but also contain other elements like sulfur and iron that help plants absorb nutrients more efficiently.

These chemicals dissolve easily in water, which means they can easily be applied directly to the ground via a sprinkler system or hose-end sprayer without the need for mixing with sand or dry granular material first

Will it hurt my pets?

While small intakes of plant food might only result in moderate belly distress, larger intakes can result in serious poisoning from iron, nitrogen as well as other chemicals. Huge ingestions of meal-based fertilizers might also develop a concretion in the stomach resulting in a digestive tract blockage or extreme as well as agonizing swelling of the pancreatic (pancreatitis). Can lawn fertilizer harm dogs? You can read more about it by clicking that link.

Contact your vet or Pet Poison Helpline for treatment recommendations if you think your dog or pet cat has eaten any fertilizer.

Which Type of Lawn Fertilizer Should You Use?

There are two main types of lawn fertilizer:

  • Quick-release
  • Slow-release

Quick-release fertilizers provide nutrients quickly so they can be absorbed by the roots and spread throughout the grass. They’re best for use in spring or fall when you want to get an instant boost of nutrients into your lawn quickly.

Slow-release fertilizers provide nutrients over time without as much risk of burning or damage to your grass from too much nitrogen at once.

How do I prepare my lawn for fertilizer?

Fertilizing the lawn is one of the most important things you can do to keep your lawn looking its best. However, if you don’t prepare your lawn properly before applying fertilizer, it may not have the desired effect.

Here are some tips on how to prepare your lawn for fertilizer:

Check your soil

The most important part is to make sure your lawn is healthy, so you should have a soil test performed first. Also, you can read my detailed article on soil and how it may be classified, and how it may behave.

The complete guide to using lawn fertilizer

Once you know what your soil needs, there are several options for feeding your lawn. If you want to ensure that your grass is getting the nutrients it needs all year long, then you can use a slow-release fertilizer that contains nitrogen, phosphorus, and potassium (NPK). 

These fertilizers are applied once every six to eight weeks throughout the summer months. Another option is to use a high-nitrogen, fast-acting fertilizer that provides nutrients quickly and then disappears. 

This type of fertilizer works well for quick results and can be used during warm weather months when grass growth slows down.

Mow it high

If you’re going to fertilize your lawn after mowing, make sure to mow it high first — about 3 inches (7.5 centimeters) tall or higher. This will allow more room for the fertilizer to be absorbed into the soil and also prevent it from being washed away by rain.

Water it down

Make sure all of the clippings from your mowing session have been removed from your lawn so they don’t get washed away by rainwater during watering or watering again later in the day.

When watering your lawn, let it sit for at least 20 minutes before fertilizing so that water penetrates deep into the soil where nutrients need to go as well as give you time for any clippings left behind to decompose so they don’t hinder nutrient uptake by roots.

Remove rocks and sticks first

Next, you’ll want to make sure that you’ve removed any rocks, sticks, and debris. This is an important step to ensure the fertilizer spreads equally in all areas.

Remove dead grass

The complete guide to using lawn fertilizer

Also, remove dead grass from the previous season by simply raking up the dead grass or cutting it down with a weed eater. If it’s still green, cut it down to about one inch above the soil level. This will stimulate new growth throughout your lawn and help prevent fungus infestations in the future.

Know how much fertilizer to apply

To determine how much fertilizer to apply, you need to know what the phosphorus and potassium levels are in your soil. Most soils are low in phosphorus (P) and potassium (K), so most lawns need to be fertilized with these nutrients.

A soil sample will tell you the exact amount of P and K in your soil. The amount of fertilizer required is based on the amounts of P 2 O 5, K 2 O, and other nutrients present in the soil sample.

What is the best lawn fertilizer schedule?

The best time to fertilize your lawn is in early spring and late summer. This is when grass plants are most active and have the best chance of absorbing nutrients. 

The complete guide to using lawn fertilizer

It’s also important to note that only 1% of a fertilizer’s nitrogen is available for plant uptake in the first 24 hours after application. 

Fertilizers should be applied at least 3-4 weeks before any expected rain or irrigation to ensure that the nitrogen is absorbed by your grass before it leaches into the groundwater.

In general, you should apply nitrogen-rich fertilizers in early spring and late summer (May through September) and phosphorus-rich fertilizers in mid-spring and late fall (April through October).

The exception to this rule is if you live in a mild climate where winter temperatures rarely dip below 25 degrees Fahrenheit or -5 degrees Celsius. In these climates, you may choose to apply all of your fertilizer at once during the spring or fall instead of splitting it up between two separate seasons.

Easy Steps for Proper Fertilizer Application

Fertilizing your lawn is one of the easiest and most effective ways to ensure a healthy, green lawn. But it’s also important to use the right amount of fertilizer and apply it at the right time. Learn how to fertilize lawn by following these simple steps.

Load the Spreader

If you’re using a broadcast spreader, make sure that all of its components are in good working order before applying any fertilizer. Check all the gears, springs, and hinges to make sure they’re not broken or worn out, and replace any broken parts as needed.

Apply the Fertilizer

Place your spreader on top of a flat surface like a driveway or cement slab. Press down on the lever until you’ve filled up about half of your spreader with fertilizer pellets or granules; then release the lever and remove any excess material before closing up your spreader again.

Clean Up

Remove any remaining fertilizer from your lawn by raking over it with a leaf rake or garden rake after spreading it out across your lawn area.


Don’t forget to take a good, long look at the lawn before you begin to apply any fertilizer. If your lawn is healthy and green, then there may not be a need for extra fertilizer. Also, look around for the best prices on fertilizer. Many stores offer discounts in the early spring and late fall when fertilizer sales tend to slow down.

Ian richardson

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