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Best Lawn Fertilizers for Your Yard

Fertilizing your lawn ensures green grass while keeping weeds at bay. There are, however, a lot of things to consider when choosing the best lawn fertilizer. Your NPK levels, for instance should vary depending on they type of grass you have or are considering growing. There are also different types of fertilizer including granular, liquid and even organic options to consider. In this guide, we’ll help you figure out when and how often to fertilize your grass, explain those important NPK numbers and talk about common grass types you can, and should, plant in Canada.

Types of Fertilizers

Finding the best lawn fertilizer is a must for a healthy yard. No two yards are the same though, so depending on the age and needs of your grass, your type of fertilizer – and how often you’re fertilizing –  may vary.

Scotts Turf Builder Starter Lawn Food.

Starter Lawn Fertilizer

Starter lawn fertilizers are specially formulated to  help your grass roots take hold in the soil, giving you the foundation you need to grow a healthy, green lawn. You’ll need to apply it every 6-8 weeks during the first growing season.

Vigoro Liquid Lawn Fertilizer.

Liquid Lawn Fertilizer

Liquid lawn fertilizer usually comes in a concentrated form, and little goes a long way. Liquid fertilizers tend to absorb more rapidly into the grass, while normal fertilizer may take a bit longer to take effect.

Scotts Turf Builder Green MAX Lawn Food.

Granular Lawn Fertilizer

Granular fertilizers are applied with a spreader, giving you an even amount over your entire lawn. Once you’ve spread it, you’ll need to water your lawn for the fertilizer to start working. Granular fertilizers are good because you can see how much you’re laying down, giving you complete control of how much you’re using in specific areas.

Scotts Lawn Response 9-1-1.

Slow-release Lawn Repair

While normal fertilizers last for about 6-8 weeks after application, slow-release fertilizers can last up to 12 weeks – meaning you won’t have to reapply as often, making it a great spring lawn fertilizer. There is also less concern about burning your lawn with a slow-release fertilizer.

Scotts Turf Builder Ultrafeed Lawn Food.

What is Organic Fertilizer?

Nutrient-dense and designed to promote optimal plant and grass growth, organic fertilizers are made from natural materials like bat guano, crushed shells, phosphate rock, certain types of wood, blood and bone meal and even ground or pulverized fish.

Understanding Lawn Fertilizer Numbers: What Does NPK Stand For?

Detailed photo of an NPK number reading “30-0-03” on fertilizer packaging.

The three numbers found on fertilizer packaging represent NPK ratios. NPK stands for nitrogen, phosphorous and potassium. NPK values, or lawn fertilizer numbers, represent the percentages of each nutrient in the fertilizer. An NPK value of 10-5-5 means that the fertilizer contains 10% nitrogen, 5% phosphorus and 5% potassium.

NPK ratios will be different for every lawn depending on the climate. Nitrogen makes your lawn green and helps it grow, potassium makes your grass hardier and more drought resistant and phosphorous is responsible for stimulating root growth while helping your seeds sprout.

Knowing When to Fertilize Grass

Spotty grass with brown patches.

The best time to fertilize your lawn is during the fall and spring. In the fall, your grass is growing and storing nutrients, making it an ideal time to feed it.

In the spring, your grass has just awoken from the winter and is hungry for nutrients to help it grow. When figuring out when to fertilize grass, you'll want to first check your local forecast. 

If there’s rain in the next day or so, it will save you water and really feed your lawn well. Avoid fertilizing a lawn that is already wet. Instead, fertilize a dry lawn and then water it for maximum effectiveness.

How Often to Fertilize Lawn

A man fertilizes his lawn with an easy-to-use drop spreader.

Best Lawn Fertilizer for Spring

Remember those NPK numbers? In spring, the best lawn fertilizer is often one with a 20-5-10 mix, assuming healthy soil. You may want to add a slow release nitrogen fertilizer in June or July as well.

Best Lawn Fertilizer for Fall

25-5-5 formula fertilizers are often the best choice for the fall months, as you typically want a nitrogen-rich blend at this time. 20-8-8 formulas can also work well if your grass growth the previous season wasn’t ideal and you feel your lawn may need some extra help growing.

How Much Fertilizer do You Need?

Figuring out how much fertilizer to use on your lawn can be tricky. In general, it’s important to remember that every eight steps you take equals roughly 10-feet. This will give you an ideal of how much fertilizer you’ll need for your lawn.

A square-footage measurement of your lawn can also be useful when you’re shopping for fertilizer.

It can also help to break up your lawn into easily measurable sections. Sketch out a rough drawing of your yard and break it into a few large squares, rectangles, circles and triangles.

  • For squares and rectangles, measure the length and the width, then multiply those two numbers to get your area. 
  • For circular areas, measure half the distance across the center of the circle then multiply by 3.14. 
  • For triangle-shaped spaces, measure the base and the height, multiply the two numbers, then divide by two.
  • Once you have the areas determined for each shape, add up the areas to get the total area of your lawn. 

How to Apply Lawn Fertilizer

First, you’ll need to figure out the square footage of your lawn. Once you’ve got that, fill a spreader with the appropriate amount of fertilizer – your fertilizer bag will have the recommended spreading setting that you should set it to. Make sure that your spreader hole is closed before pouring fertilizer in the hopper. Push the spreader while walking forward, never pull it backwards. The fertilizer should spray out in a fan shape. Continue to spread your fertilizer until you’ve achieved the appropriate coverage. Once complete, water your lawn to finish the fertilizing process.

How to Choose the Best Fertilizer for Grass Types

The type of grass you currently have or the type you plan to grow play a major role in choosing the best type of fertilizer. Cool season grass found in much of Canada grows slowly and tends to go dormant in the summer. That’s why fertilizing in the spring and again in the fall is typically your best bet. Fertilizer packaging is labeled by grass type as well, which can help you choose the best lawn fertilizer for your yard.

Tall Fescue Grass.

Tall Fescue

A perennial, cool-weather favourite, tall fescue is a dark green colour that grows in bunches instead of the more standard horizontal spread blade look. A slow-release fertilizer with higher nitrogen and potassium levels works best here.

Perennial Ryegrass Grass.

Perennial Ryegrass

Another ideal cool-weather grass, perennial ryegrass is a rich green colour that shines in most yards. It’s also low maintenance and pest-resistant, making it an ideal pick for homeowners that prefer reduced yard maintenance. Fertilizers with low nitrogen, high phosphorus, and high potassium levels work best for ryegrass.

Kentucky Bluegrass Grass.

Kentucky Bluegrass

Dense and downright durable, Kentucky bluegrass is a brilliant choice for most yards. This grass prefers full sun, but yards with some shady spots can still grow Kentucky bluegrass with relative ease, as long as you use the right fertilizer and maintenance routine. A balanced fertilizer with even NPK levels is the best bet for bluegrass.

A man rakes leaves on a lawn.

How to Prepare Grass for Lawn Fertilizer

When preparing your lawn for fertilizer, make sure to rake it through – removing any debris or clumped up grass that may have accumulated. Be sure to repair any bald or dead spots prior to fertilizing.

A lawn aerator can also be useful since it will help you puncture small holes into the soil, allowing your water and fertilizer to penetrate deep into the roots of your lawn. This extra step is well-worth the effort in most yards, particularly those with dense, compact soil.

A large weed growing in grass.

Fix Common Lawn Problems

Quality fertilizer can also help keep serious problems that impact your lawn at bay.

Fertilizer products that contain imidacloprid, thiamethoxam and clothianidin can help kill grubs.

Some products also contain herbicides that can reduce weeds and crabgrass. Just as important, even organic fertilizers help create a healthy lawn, which means fewer weeds, dandelions and a brighter, greener colour.

A man pushes a green lawn spreader filled with fertilizer across grass.

How to Apply Lawn Fertilizer

First, you’ll need to figure out the square footage of your lawn. Once you’ve got that, fill a spreader with the appropriate amount of fertilizer – your fertilizer bag will have the recommended spreading setting that you should set it to. Make sure that your spreader hole is closed before pouring fertilizer in the hopper.

Push the spreader while walking forward, never pull it backwards. The fertilizer should spray out in a fan shape. Continue to spread your fertilizer until you’ve achieved the appropriate coverage. Once complete, water your lawn to finish the fertilizing process.

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