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Lawn Fertilization: How and When to Feed Your Lawn

August 1, 2022

What is Lawn Fertilization

Lawn fertilization is the process of applying three elements to your grass to improve the health, growth, and lusciousness of your yard.

Lawn fertilizers tend to have three main ingredients: nitrogen, phosphorous, and potassium. Each ingredient is responsible for promoting a different aspect of healthy lawn growth.

Nitrogen (N)

Nitrogen helps with proper lawn growth and green colour.

Phosphorous (P)

Phosphorous is crucial in developing healthy root systems. Fertilizers for new lawns have high concentrations of phosphorous while established lawns contain a relatively low percentage of phosphorus.

Potassium (K)

Potassium helps with drought protection, cold tolerance, and disease resistance and promotes the overall health of your lawn.

How to Pick a Lawn Fertilizer

One of the most important aspects of picking a product to properly fertilizing your lawn is being able to read and understand the label. Each lawn is different so before you buy a fertilizer, make sure to read the product descriptions carefully and decide whether that particular fertilizer is right for you.

Fertilizer labels will have a three-number sequence that lists the Nitrogen, Phosphorous, and Potassium proportions of the fertilizer.

Nitrogen – Phosphorous – Potassium

For example, many all-purpose fertilizers will have a label that reads 10-10-10. This means that the fertilizer contains equal proportions of Nitrogen, Phosphorous, and Potassium.

Here are four main lawn types and the types of fertilizer you want to use for each one.

Established Lawn

An established lawn needs nitrogen more than it needs anything else. In this case, we advise getting a fertilizer with a number that reads Big Number – Small Number – Small Number.

Stressed Lawn

A stressed lawn (a lawn that’s been through or you expect to go through extreme cold or extreme heat) needs a decent amount of nitrogen and a ton of potassium to develop its hardiness and resistance to weather extremities. In this situation, you’ll likely want to get a fertilizer with a number that reads Big Number – Small Number – Big Number.

New Lawn

A new lawn doesn’t have much in terms of a root system so it needs plenty of phosphorous to develop one. We suggest a fertilizer with a number sequence that reads Small Number – Big Number – Big Number.

New Sod

New sod needs phosphorous and potassium to develop a root system and cultivate a tolerance to cold and disease. We recommend a fertilizer with a number that reads Small Number – Big Number – Big Number.

Fertilizers: Liquid versus Granular

Now that you have hopefully picked your proportions of Nitrogen, Phosphorus, and Potassium, it’s time to choose between a liquid or granular fertilizer.

Before we begin, it is important to think about how you will spread your fertilizer and consider any equipment limitations. Do you want to apply liquid fertilizer with a hose or would you rather push a broadcast spreader using granular fertilizer? Let’s now explore each in turn.

Liquid Fertilizers

In short, liquid fertilizer applications provide better coverage because you know exactly where you are spraying. Liquid fertilizers also do not rely on watering your lawn or waiting until the next rainfall to activate. On the other hand, liquid-based fertilizers do not release as slowly over a sustained period compared to granular fertilizers. Lastly, liquid fertilizers may not keep as well if not used compared to granular fertilizers. This is because of sediments in liquid which may set to the bottom when not used. We recommend shaking the liquid before using it again for another season.

Granular Fertilizers

Granular fertilizer applications, on the other hand, can be more cost-effective when purchasing in bulk. They also are able to release more slowly if coated with a polymer and may require fewer applications over the season compared to liquid fertilizers. The downside is that granular fertilizers require water to activate, so if you’re in a drought they will just stay on the lawn unless you bring out the sprinkler. They also have less uniform coverage as they are broadcasted out from a spreader.

What Fertilizer Numbers to use in Spring

After a cold winter, your lawn is in need of a healthy growth spurt. We recommend 20-5-10 which is heavier on nitrogen and potassium relative to phosphorus.

When to Apply Fall Fertilizer

Applying fertilizer in the fall before the cold and snowy winter months is crucial for sustained lawn health. We suggest looking at the weather and ensuring you apply fall fertilizer at least two to three weeks before the temperature drops below freezing. Depending on where you live, this will fall between mid-September to early November.

Best Lawn Fertilizers

With all the lawn fertilizer brands on the market, it can be challenging to make a choice. These brands will also have different lines of products which makes decision-making even more stressful. Some of our favourite brands are Miracle-Gro, Nutrite, Safer Brand, and Scotts.

Miracle-Gro Lawn Food


Nutrite 32-2-10 Nutryon Season Long


Nutrite 20-5-15 75% FMS


Safer Brand Lawn Restore


Scotts Green Max Fertilizer


Quick, green, results and accurate applications.

Mid to late-Spring. Extra-slow release provides up to six months of fertilization from 90% slow release nitrogen.

Multiple release rates including fast, medium, and slow for up to 4 months. Designed to provide early, lush, green colour with months of consistent growth.

For those that like organic lawn fertilizers and want a fertilizer that can be used on both lawn and in gardens.

Quick results for the busy homeowner. Apply every 6-8 weeks.

How Much Fertilizer to Use

Applying the correct amount of fertilizer is just as important, if not more so, than choosing your fertilizer. If you apply too little fertilizer, you won’t see the results you are hoping to achieve. If you apply too much fertilizer, you run the risk of burning your grass or killing your plants. Again, we recommend following the label. Below are the amounts of fertilizer to be used for the products mentioned earlier.

Amount of Fertilizer

With the Miracle-Gro® Garden Feeder: One feeder refill packet in the Miracle-Gro® Garden Feeder will cover 1000 square feet in approximately 12 minutes.

Apply at 6.25 lb/1,000 square feet when only one application of fertilizer is to be made during the season. Apply at 5 lb/1,000 square feet rate when used in combination with fertilizers in shoulder seasons.

Apply 5lb/1,000 square feet

Apply 4lb/1,000 square feet

Apply 3.3lb/1,000 square feet

How many weeks between each lawn fertilization

Generally, early-fall and mid-spring are the best and most important times to fertilize your lawn. Make sure to apply fertilizer during these two periods as they set the stage for how your lawn will grow throughout the summer season. If you can, apply all-purpose fertilizer every 6 to 8 weeks throughout summer to make sure your lawn gets all of the nutrients it needs. If you want to spend more, the Nutrite options may only need to be applied once or twice per season.

When to water the lawn after fertilization

If you decide to go with granular fertilizer, you will need to make sure that it becomes activated by water – either from a hose or from the clouds above. All products are different, so we recommend reading the label on your specific fertilizer. Some recommend watering immediately, while others require you to wait a few days because they are mixed with weed control products that would be washed away with immediate watering.

Final Thoughts

We hope you learned more about lawn fertilization in this article! If you have any questions about fertilization or yard care, please feel free to reach out by email at [email protected].

Yardly offers a range of home care services including snow removal, lawn mowing, spring and fall cleanups, and fertilization and weed control if you need any assistance.