The best lawn fertilizers give your lawn nourishment to grow thick and strong. It may be able to get most of the nourishment it needs from your soil. But at certain times of the year, you need to give it a boost with good lawn fertilizer.
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Here is my selection of the best lawn fertilizers.
Best Lawn Fertilizer
- Scotts Turf Builder Starter Food for New Grass
- BioAdvanced 100532514 Weed & Feed Crabgrass Killer Science-Based Solutions Lawn Fertilizer
- Espoma Organic Lawn Booster Fertilizer
- Espoma Organic All Season Lawn Food, 28-Pound
- Scotts Turf Builder Summer Lawn Food
- Espoma Organic Fall Fertilizer
- Scotts Turf Builder Winterguard Fall Lawn Food
What Is Lawn Fertilizer?
The three core ingredients in any lawn fertilizer are nitrogen, phosphorus, and potassium.
- Nitrogen promotes green, leafy growth above ground
- Phosphorus promotes vigorous root growth
- Potassium is generally beneficial for plants.
Lawn fertilizer is generally described in terms of the nitrogen, phosphorus, and potassium ratio. This is usually called the N-P-K ratio (K is the chemical symbol for potassium).
The N-P-K ratio shows how much fertilizer you would need to apply to deliver 1 pound of the desired nutrient. You calculate this by dividing 100 by the given number.
For example, if an N-P-K ratio is 24-25-4 then it takes (100/24) 4.17 pounds of lawn fertilizer to deliver 1 pound of nitrogen. Likewise, it takes (100/25) 4 pounds of lawn fertilizer to deliver 1 pound of phosphorus and (100/4) 25 pounds of lawn fertilizer to deliver 1 pound of potassium.
In addition to the main nutrients, lawn fertilizers may also contain secondary nutrients and/or micronutrients. Secondary nutrients are nutrients that are required in smaller quantities than the main nutrients but larger quantities than the micronutrients. Micronutrients are very small quantities of nutrients.
The secondary nutrients for lawn grasses are calcium, magnesium, and sulfur. The key micronutrients for lawn grasses include boron, chlorine, cobalt, copper, iron, manganese, molybdenum, nickel, silicon, selenium, sodium, and zinc.
You can expect any lawn fertilizer to contain nitrogen. Lawn fertilizers may or may not contain phosphorus, potassium, secondary nutrients, or micronutrients.
Some lawn fertilizers also contain weed killer. These are generally known as “weed and feed” lawn fertilizers and can be more cost-effective than separate products.
Why Iron Is Important
Iron is important in the production of chlorophyll. Chlorophyll is essential to photosynthesis (the process by which plants convert sunlight into energy). It is also what gives plants, including lawn grass, their green color.
If lawn grass loses its green color and becomes yellow, but is not dehydrated, then it may be due to a lack of iron. You could try treating it with a lawn fertilizer that includes iron or applying an iron treatment on its own.
Pet Safe Fertilizer
The manufacturer’s description will usually provide information about pet safety. Some lawn fertilizers, especially organic ones, will be pet-safe from the moment you apply them. Others will be pet-safe after a certain length of time, provided that you follow the manufacturer’s instructions for application. Is Scotts Turf Builder safe for pets?
In particular, you need to be careful to apply the lawn fertilizer in the recommended concentration. If you apply it at a stronger concentration, then it may take longer for your lawn to become pet-safe (and you may burn your lawn in the process).
Organic Fertilizer
Organic lawn fertilizer is any lawn fertilizer that is made totally from plant and/or animal matter (rather than artificial chemicals). Organic lawn fertilizers tend to be much slower-acting than chemical lawn fertilizers because their components need to be brokenover a period of time. On the plus side, however, their effect will also tend to last longer.
Organic lawn fertilizers are often promoted as a more environmentally-friendly option than non-organic fertilizers. It is true that organic lawn fertilizers tend to be less prone to leaching and hence are less likely to damage the water supply. That said, they still contain nitrogen and they can still leach so they can still harm the environment unless you take suitable precautions when using them.
Similarly, it’s harder to burn your lawn with an organic lawn fertilizer than with a non-organic lawn fertilizer. There is, however, a difference between “harder” and “impossible”, so again take appropriate precautions when applying it.
Non-commercial Organic Fertilizer
Non-commercial organic fertilizer can be an affordable way to improve the condition of your soil. You do, however, need to be careful about what non-commercial organic fertilizer you use and how you use it. this type of fertilizer is usually much safer for dogs and other pets.
Grass Clippings
If you leave the grass clippings on your lawn after you mow it, then you are essentially getting free, nitrogen-rich organic lawn fertilizer. If you don’t want to leave grass clippings on your lawn, then you could use them for compost or for mulching.
Animal Manure
Animal manure (and poultry litter) can deliver a lot of nutrients for a very affordable price. It must, however, be well composted before use. Fresh animal manure can contain undesirable materials such as pathogens and weed seeds. It can also cause burning.
Wormery Liquid
Wormery liquid is an excellent fertilizer. Just remember to dilute it before application. The general rule is that it should look like weak tea. That’s about one part of wormery liquid to ten parts of water. But check the product instructions as some manufactures may differ.
Fertilizing The Lawn
Fertilizer should either replace missing nutrients in your soil or boost existing ones. You need to know the composition of your soil to choose the right lawn fertilizer for it. Ideally, you should undertake a soil-analysis test each year as the composition of your soil may change over time.
In addition to choosing the right lawn fertilizer, you need to apply it in the right way. Here are the steps to follow.
Prepare The Ground
In spring and summer, rake your lawn lightly to get rid of surface debris without damaging new growth. Then give your lawn a gentle mow and leave it to rest for two or three days.
In fall, you don’t have to worry about new growth so rake your lawn thoroughly to get rid of all thatch. Then level off any bumps with a spade or a fork. Do not use a roller as it will compact the soil, which may create drainage issues. Check that your lawn is draining as it should. If not, aerate it. Mow the grass and leave it to rest for two or three days.
Prepare The Lawn Fertilizer According To The Manufacturer’s Instructions
If you’re using soluble lawn fertilizer and want to apply it as a liquid, then use the exact quantities stated on the packaging. Always measure and never guess.
If you’re using solid lawn fertilizer (e.g. powder or granules) then you need to apply it at exactly the rate specified by the manufacturer. The easiest way to do this is to invest in a spreader.
If you must apply lawn fertilizer by hand then you need to be really careful to apply exactly the right quantity of lawn fertilizer evenly across your lawn. Get this wrong and you’ll probably end up with burnt patches (where you’ve applied too much lawn fertilizer) and malnourished/bare patches (where you haven’t applied enough lawn fertilizer).
Apply The Lawn Fertilizer In The Right Conditions
Lawn fertilizer has to get into the soil rather than just sit on top of it. The soil underneith has to be soft enough to be absorbent but not overly-saturated with water.
Very hot and very cold weather can both leave soil too hard to absorb lawn fertilizer. If the weather has been particularly hot, then watering your lawn may solve the problem. If, however, the weather has been very cold, you’ll generally just have to wait until it warms up. Likewise, if you’ve had a lot of rain, then, again, you’ll just have to wait until your lawn is dry enough to absorb lawn fertilizer.
If you’re using organic fertilizer then be aware that you’ll be dependent on soil microbes to break down the large nutrient molecules in the lawn fertilizer so that they become small enough for your lawn grass to absorb. These soil microbes function best in mild, slightly damp conditions. This means that if you are experiencing severe weather of any sort (hot, cold, or wet) then it will probably take longer for your grass to benefit from the lawn fertilizer.
Finally, if you’re planning to apply powdered or granulated lawn fertilizer, you need minimal wind (preferably none at all).
Protect Your Newly-fertilized Lawn
If you have used solid lawn fertilizer then it’s best to water-in your lawn fertilizer immediately. Saving you the trouble of having to protect your lawn until the rain arrives.
If you do leave solid lawn fertilizer on your lawn, be aware that non-organic fertilizer can be very dangerous to children and animals. Organic fertilizer, by contrast, can smell very tempting to animals (and some birds) as it often contains blood. If you leave it unattended and unprotected, you can find it literally gets eaten before the rain comes.
What’s more, regardless of what kind of lawn fertilizer you use, if the wind gets up, it can easily blow solid lawn fertilizer off your lawn.
Even after your lawn fertilizer has been watered in, you may still need to keep people and animals off your grass for a while. Check the packaging for guidance.
Clean Up Any Excess Lawn Fertilizer
If you apply solid lawn fertilizer, then it’s very easy for some of it to land on hard surfaces such as garden paths, especially if there is any sort of wind. If it’s left there, it will be dissolved the next time the rain comes, and then it may end up in the water supply either via a drain or via a waterway. This is really bad for the environment so take the time to clean up any excess lawn fertilizer.
Liquid lawn fertilizer doesn’t really have this issue, but if you spill any do make the time to clean it up properly rather than waiting for it to be washed away. This also prevents children and animals from drinking it.
How Often To Fertilize A Lawn?
The key time to fertilize a lawn is in spring when new growth is due to start. Deciding if your lawn needs to be fertilized in summer will depend largely on where you live.
If you live in a cooler location, like the northern states in the U.S. then your grass is unlikely to grow much in summer. This means that it will need minimal to no fertilizer. In a warmer climate, for instance, the southern US states and are growing “warm-season grasses” (e.g. Bermuda grass), then you will potentially need to use lawn fertilizer at least up until mid-summer.
You may also want to apply lawn fertilizer in fall, especially if you live in a cooler climate. This can help to put your lawn in the best possible condition before the arrival of winter.
You do not fertilize a lawn in winter, not even if the weather is mild. This is not the time to encourage new growth. It’s the time for your lawn to rest. Ideally, keep people and animals off it completely, but if you know it’s going to be used as a walkway, try to limit where people walk. If possible lay down a designated path.
How To Choose Fertilizer For Your Lawn
In spring, you generally want nitrogen-rich lawn fertilizers to encourage green, leafy growth above ground. This is not only what makes your lawn look like a lawn, but it’s also what smothers weeds. In summer, you may want green, leafy growth but if the weather is particularly harsh, you might want to think about strengthening your grass’ roots. That means phosphorus and/or potassium.
In fall, the priority is generally root strength. You want to be sure that your grass can, literally, hold on despite what the weather is going to throw at it. If the weather is mild, you might want to try for a bit of green, leafy growth so that your lawn goes into winter looking its absolute best. This means that you generally want to go for lawn fertilizers with plenty of phosphorus and/or potassium, but you may also want a decent amount of nitrogen.
Best Lawn Fertilizer
Here are the 7 best lawn fertilizers available right now
Scotts Turf Builder Starter Food for New Grass
N-P-K – 24-25-4
Click here for the latest price
According to the manufacturer, this makes new grass grow over two-thirds thicker and over one-third quicker than it would without feeding. It’s not clear how they measure this, but it certainly does promote strong root growth. This means it could also be a good option as a lawn fertilizer for fall.
BioAdvanced Weed & Feed Lawn Fertilizer
N-P-K – 22-0-4
Click here for the latest price
As a lawn fertilizer, this is all about the nitrogen. It really promotes growth, which is what you need if you’re battling a weed infestation. This lawn fertilizer also does a very decent job of killing both broadleaf and grassy weeds, including crabgrass. Not for sale in the following states: HI, NY, FL
Espoma Organic Spring Lawn Booster Fertilizer
N-P-K – 8-0-0
Click here for the latest price
This organic lawn fertilizer is all about the nitrogen for growth. It does the job, but also has a powerful smell compared to other lawn fertilizers. That said, the mild formula makes it much harder to burn your lawn if you accidentally overdo it.
Espoma Organic All Season Lawn Food
N-P-K – 9-0-0
Click here for the latest price
This is almost the same as the Booster option above, but has a bit more nitrogen.
Scotts Turf Builder Summer Lawn Food
N-P-K – 34-0-0
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This lawn fertilizer combines a super-high nitrogen content with “Everydrop” technology. Everydrop technology was created to encourage water to penetrate hard soils. According to the manufacturer, it can reduce water usage by up to half.
Again, it’s not clear how this is measured. It is fair to say that this lawn fertilizer definitely keeps lawns greener during the summer heat.
Espoma Organic Fall Fertilizer
N-P-K – 8-0-6
Click here for the latest price
This lawn fertilizer is essentially the Espoma Lawn Booster but with added potassium. This helps to promote all-round strength, including root strength, to see your lawn through the winter.
Scotts Turf Builder Winterguard Fall Weed & Feed
N-P-K – 32-0-10
Click here for the latest price
The high nitrogen content in this lawn fertilizer encourages your grass to make one last push for growth above ground before winter comes. The potassium content adds general robustness including root strength. Overall, if your lawn is looking the worse for wear towards the end of fall then this lawn fertilizer could be just what it needs.
Summary
Using lawn fertilizer makes sure that your lawn gets the nutrients it needs to grow thickly and strongly. The key ingredients in lawn fertilizer are nitrogen, phosphorus, and potassium. Lawn fertilizer may also contain other nutrients and/or weed killer.
Whatever kind of lawn fertilizer you choose, you need to apply it correctly. Make sure that you prepare the lawn appropriately and follow the manufacturer’s instructions for preparing and applying the lawn fertilizer. Apply the lawn fertilizer in the right conditions, protect your newly-fertilized lawn appropriately, and be sure to clean up any excess fertilizer.
Other Resources
https://www.rhs.org.uk/advice/profile?pid=304
https://extension.usu.edu/waterquality/agriculturewq/fertilizer
