As you’re probably aware, applying lawn fertilizer is the key to getting a yard full of lush, green grass that’s hardy and resistant to yellow patches. But with so many brands and variations on the market that all promise different results, how do you know which lawn fertilizer is the best?
Lawn fertilizers come in many different forms, the main four of these being organic, inorganic, granular, and liquid. While all fertilizers work to enrich the soil with the three primary nutrients needed by plants to grow, the ratio of each nutrient present varies depending on the stage of plant growth that the fertilizer has been specially formulated for. Some fertilizers also promise additional benefits for your lawn, such as weed and insect control.
Read through this guide to understand what you should look out for when buying fertilizer for your new or existing lawn, as well as some of our recommendations on which products that we consider to be the best lawn fertilizer for your lawn type.
Quick Look: Our Top Picks for Best Lawn Fertilizer
Buyer’s Guide to Picking the Best Lawn Fertilizer
Understanding NPK Ratios on Lawn Fertilizer Labels
All lawn fertilizers contain three main ingredients in varying quantities: Nitrogen (N), Phosphorus (P), and Potassium (K). These three substances are plants’ ‘primary nutrients’, and they all play an essential role in the germination and growth of your new grass seedlings.
- Nitrogen (N) makes grass lush and green, and promotes fast growth
- Phosphorous (P) helps grass to develop strong, healthy root systems
- Potassium (K) protects grass from disease, drought, and cold temperatures
Plants have changing requirements of these nutrients as they progress through the stages of germination and growth. For this reason, the quantity of each primary nutrient in each fertilizer varies from product to product. Each products’ formulation depends on what type of fertilizer it is and what stage of growth it’s designed for.
You can find out the quantity of each primary nutrient present in a given fertilizer by looking at the packaging and finding the NPK number. This number indicates the percentage of each of these nutrients present by weight. From this number, you can get an idea of how much of each nutrient is in the mix relative to the other ingredients.
To use a common all-purpose fertilizer ratio as an example, an NPK number can be 10-10-10. This means that the fertilizer contains 10 percent nitrogen, 10 percent phosphorus, and 10 percent potassium, with the rest of the ingredients being supplemental nutrients and filler material.
Organic vs Synthetic Lawn Fertilizer
Depending on their ingredients and production, fertilizers are classed as either organic or synthetic.
- Made of naturally occurring sources of the primary nutrients
- Slow-release, gradually enriches soil with nutrients over time as the organic material breaks down
- Possible to either purchase or make at home
- Tend to be more expensive than inorganic fertilizers
- Made of a synthesised mixture of the primary nutrients
- Quick-release, enriches soil immediately as it comes in a format that is readily taken up by plants
- Tend to be less expensive than organic fertilizers
Granular vs Liquid Lawn Fertilizer
- Made of pellets or coarse powders that can contain organic or inorganic materials
- Slow-release, gradually enriches soil over time as it breaks down with every watering
- Available in varying time-release formulas
- Gives you more control over your lawn care schedule
- Made of a liquid that can contain organic or inorganic materials
- Quick-release, enriches soil immediately as they’re designed to be taken up readily by plants
- Many types are packaged in a bottle that attaches directly to the end of a hose for convenience during application
Lawn Fertilizers with Additional Benefits
In addition to enriching the soil with supplementary nutrients, fertilizers can be formulated to provide extra benefits such as weed and pest control. We have listed some of the types of fertilizers that provide additional benefits to a lawn beyond fertilization.
Pre-emergent Weed Control Fertilizer
- Also known as ‘weed & feed’
- Feeds your lawn at the same time as working to prevent weeds
- Encourages and strengthens root system growth
- Used on already-established lawns
- Made of a nitrogen rich formula
- Revives an old lawn from dull grass to grass with a lush green colour
Moss and Fungus Control Fertilizer
- Kills moss and fungus
- Doesn’t damage grass surrounding the application area
Lawn Weed Killer
- Usually comes in liquid form, occasionally in granular
- Depending on the product, can kill crabgrass, black clover, chickweed, and other unwanted growths
Lawn Insect Control
- Can be applied in the grass’ growing or dormant season
- Manages unwanted insects such as ants, ticks and fleas
- Applied using a broadcast or rotary spreader
Weed and Grass Killers
- Kills grass and weeds completely
- Used to clear areas of unwanted growth
- Usually very fast-acting
Selecting the Best Lawn Fertilizer for Your Grass Type
Before you can decide what the best lawn fertilizer is for your lawn, you need to take into consideration what type of grass you have. All grass species fall under one of two categories, being either warm-season grasses or cool-season grasses, so determining which of these are growing in your lawn is essential to picking the ideal fertilizer that will give you the results you’re looking for.
Warm-season grasses prefer warmer, more southern climates. They see vigorous growth throughout much of the year, therefore they require a bit more attention in their fertilization schedule than cool-season grasses do. The most common types of warm-season grasses include Bahia, Bermuda, Centipede, Zoysia, Carpet grass, and St. Augustine.
Cool-season grasses prefer cool climates and are more often found in northern regions. They grow and thicken at a slower rate than warm-season grasses. They also require less attention to their fertilization schedule as they are usually semi-dormant during the summer months, meaning you can limit fertilizations to twice a year – once at the beginning of spring, and once again at the beginning of fall. The most common types of cool-season grasses include Fescues, Kentucky Bluegrass, Bentgrass, and Ryegrass.
Best Lawn Fertilizer Reviews for 2021
1. Espoma EOLF28 Organic All Season Lawn Food (Best Organic Lawn Fertilizer)
- For a healthy lawn
- Organic formula
- Size 18 pounds
- Covers 5000 feet
- With BioTone microbes
Our top pick for the best organic lawn fertilizer is Espoma EOLF28 Organic All Season Lawn Food. This fertilizer can be used on any grass type to promote the natural growth of thick, healthy grass.
The NPK ratio of Espoma EOLF28 Organic All Season Lawn Food is 9-0-0. This ratio makes this fertilizer an ideal choice for an established lawn, as the high nitrogen content will help to boost the growth and health of your grass. The nitrogen will also help to green up grass that has turned yellow or patchy.
As this fertilizer is completely organic, it is environmentally friendly, as well as being completely safe for use around your children or pets.
2. Scotts Green Max Lawn Food (Best Synthetic Lawn Fertilizer)
- Feeds for deep greening in just 3 days
- Dual-action, 2-in-1 formula feeds and supplements with iron
- Guaranteed not to stain when used as directed
- Apply to any grass type
- Recommended for many lawns as part of the Scotts Lawn Care Plan
Our pick for the best synthetic lawn fertilizer is Scotts Green Max Lawn Food. This fertilizer is suitable for any grass type and promises to feed your lawn for fast deep greening of your grass.
This synthetic lawn fertilizer has an NPK ratio of 27-0-2, meaning it contains a high amount of nitrogen, no phosphorous, and a small amount of potassium. It also contains additional iron supplements that enhance the fertilizer’s greening effect.
Even though organic fertilizers are a better option for the good of the environment, synthetic fertilizers like Scotts Green Max Lawn Food work much more quickly to deliver the same nutrients to your grass. You will see the effects of this fertilizer after just three days.
3. Scotts Turf Builder Starter Food for New Grass (Best Lawn Starter Fertilizer)
- Grows new grass 70% thicker, 35% quicker versus unfed grass
- Improves seeding results--also great for sod and grass plugs
- 24-25-4 fertilizer ratio provides the nutrients for developing lawns
- Safe for any grass type, whether you're planting new grass, starting a new lawn, or reseeding an existing one
- Covers 5,000 sq. ft.
The best fertilizer for new grass is Scotts Turf Builder Starter Food. This fertilizer guarantees the growth of thicker and greener grass on reseeded or entirely new lawns.
Scotts Turf Builder Starter Food is a starter fertilizer, meaning it contains nutrients in the ideal ratio for newly sown grass seed. It has an NPK ratio of 24-25-4, as it contains nitrogen and phosphorus in equal amounts in addition to a small quantity of potassium.
This fertilizer is safe to use on newly planted grass of any species or type, including grass plugs and newly laid sod. It will help your seedlings to become well-established in the soil, encouraging them to grow into strong, resilient grass plants.
4. Scotts Turf Builder SummerGuard Lawn Food with Insect Control (Best Summer Lawn Fertilizer)
- Feeds and strengthens your lawn against heat and drought
- Kills and protects against listed bugs including armyworms
- Won't burn lawn
- Your lawn will begin to wilt when water is needed; take advantage of nature's sprinkler and rely on the rain to water your lawn
- A healthy lawn can clean the air, produce oxygen, prevent runoff and reduce soil erosion
For summer fertilization, the best fertilizer to use is Scotts Turf Builder SummerGuard Lawn Food with Insect Control. This fertilizer works to strengthen grass against the stress of heat and drought during the summer season, having the added benefit of insect control.
Scotts Turf Builder SummerGuard Lawn Food has an NPK ratio of 20-0-08. It will feed your lawn with the nutrients needed to protect the grass over the hotter summer months. In addition to providing the grass with nutrients, this fertilizer acts as an insecticide against a number of pests, including armyworms, ants, chiggers, fleas, ticks, spiders, and more.
This fertilizer is safe for use on any grass type during the summer months.
5. Scotts Turf Builder WinterGuard Fall Weed & Feed (Best Fall Lawn Fertilizer)
- Scotts Turf Builder WinterGuard Fall Weed & Feed3 weed killer and lawn fertilizer controls weeds and feeds grass in the fall for a better lawn next spring
- Fall weed and feed kills over 50 listed lawn weeds, including clover, dandelion, plantain, morning glory, chicory, evening primrose, and purslane
- Apply weed control plus grass fertilizer to a wet lawn when weeds are actively growing and temperatures are consistently between 60°F and 90°F
- Do NOT apply to the following grass types: St. Augustinegrass, Floratam, Dichondra, Lippia, Carpetgrass, Bentgrass
- One 14.29 lb. bag of Scotts Turf Builder WinterGuard Fall Weed & Feed3 covers 5,000 sq. ft.
For fall fertilization, our pick is Scotts Turf Builder WinterGuard Fall Weed & Feed. This fertilizer provides grass with the nutrients it needs to recover from the summer season’s heat and drought stress, while simultaneously strengthening the grass’ roots with the nutrients they need to survive the stressful conditions of winter.
The NPK ratio of Scotts Turf Builder WinterGuard Fall Weed & Feed is 28-0-6. In addition to delivering nutrients to the lawn, this fertilizer also improves the grass plants’ ability to absorb nutrients and water. It strengthens the grass plants by encouraging them to grow stronger, deeper roots. On top of this, Scotts Turf Builder WinterGuard Fall Weed & Feed will also get rid of weeds on your lawn like dandelion, clover, crabgrass, and more.
This fertilizer is safe for use on any grass type in fall to prepare it for the next growing season in the following spring.
6. Scotts Turf Builder Triple Action (Best Weed and Feed Lawn Fertilizer)
- Scotts Turf Builder Triple Action is a three-in-one formula that kills weeds, prevents crabgrass, and feeds grass to build thick, green lawns
- Controls existing listed lawn weeds, including dandelion, clover, dollarweed, ground ivy, chickweed, plantain, henbit, and english daisy
- Prevents crabgrass for 4 months (will not kill existing crabgrass); prevents other listed grassy weeds from invading your lawn
- For use on Bahiagrass, Centipedegrass, Kentucky Bluegrass, Perennial Ryegrass, Bermudagrass, Tall Fescue, Fine Fescue, and Zosyiagrass
- Apply to a wet lawn with a Scotts spreader, and then water in after 24 hours; apply in early spring when dandelions are actively growing; a 20 lb. bag treats 4,000 sq. ft.
If you want to fertilize your lawn at the same time as protecting it from weed growth, choose Scotts Turf Builder Triple Action weed and feed fertilizer. This fertilizer not only provides your grass plants with a boost of nutrients, but also kills and prevents the regrowth of a number of weeds.
Scotts Turf Builder Triple Action has an NPK ratio of 16-0-1. The types of weeds it is able to kill on contact include clover, dollarweed, ground ivy, chickweed, plantain, henbit, and english daisy. It will also work to prevent the growth of invasive grassy weeds like crabgrass throughout the growing season.
Take note that this fertilizer is not suitable for use on every type of grass; it is only suitable for use on Bahiagrass, Centipedegrass, Kentucky Bluegrass, Perennial Ryegrass, Bermudagrass, Tall Fescue, Fine Fescue, and Zosyiagrass.