Lawn Fertilization: How To Feed And Fertilize Like A Lawn Care Ninja

Pinterest Hidden Image

Lawn fertilization that’s a big topic and a major part of lawn care! If you want a healthy green lawn the grass will need fertilizer. You’ll find all kinds of fertilizers for grass on the market:

Lawn Fertilization: How To Feed And Fertilize Like A Lawn Care NinjaPin

However, for most homeowners a complete lawn fertilizer will do the job.

We get questions like this all the time:

I want to know about fertilizing our lawn. Sorry to say, my dad always took care of our yard when I was young. We always had a green lush carpet to play on as kids, but my dad is no longer living and I cannot go to him for lawn care advice.

I went to the garden center but the “kid” did not seem old enough to know what to do. Can you help with my lawn fertilizing dilemma? Allie, Rochester, Minnesota

The Answer on Grass Fertilization

For Allie and so many others questions on fertilizing the lawn become a popular topic during the spring months when lawns start to green up. Let’s start with some basics.

Understand that grasses that make up a lawn exist in tough and unnatural environments. Lawns battle it out with:

  • Mowers
  • Weed-eaters
  • Trees
  • Shrubs
  • Mother Nature’s blazing heat
  • Heavy rains…
  • Lawn Fungus – depending on grass variety
  • Lawn Pests
  • and let’s not mention weed control.

With all this “fighting” the task of providing a complete, balanced diet by applying some form of lawn fertilization to grass is a must. When properly feed (on a fertilizer schedule) and managed a healthy lawn can combat weeds, insects, and diseases. The grass will be full and thick, have strong root growth, good color and grow with vigor.

Essential Food Elements in Fertilizing The Lawn

Let’s take a look at the essential lawn food elements which all plants must take from the soil for proper growth.


These are nitrogen (N), phosphorus (P) and potassium (K), along with numerous other elements needed in much smaller quantities. In most good soils you’ll find the latter elements present. In a commercial fertilizer for grass they exist as impurities or added “trace elements.”

Plants need nitrogen, phosphorus, and potassium in relatively large quantities. It’s why these elements need replacing in the soil in order to “feed” the plants.

It’s around these three elements we find dozens of fertilizer formulas developed. Each type of fertilizer meets a specific crop need or corrects unusual soil deficiencies. (A soil test will show any deficiencies)

Do not let the numbers on the fertilizer label trip you up. Read our article explaining: What is NPK ratio in fertilizer

Reading The Fertilizer Label

Every bag of fertilizer carries a label giving the minimum percentage content of nitrogen (N), phosphorus as phosphoric acid (P2O2) and potassium as potash (K2O).

The percentages are always listed in the same order NPK, and referred to commercially as the “grade.” Thus, a 4-12-4 grade fertilizer contains 4 percent nitrogen, 12 percent phosphoric acid, and 4 percent potash.

A 10-6-4 grade (for use on lawns, golf courses, parks and other areas of well-groomed turf) contains 10 percent nitrogen, 6 percent phosphoric acid, and 4 percent potash.

Because the nitrogen carriers are the most expensive part of fertilizers, the 10-6-4 grade costs more per pound than does the 4-12-4, although each contains 20 units of plant food.

However, to get corresponding quantities of nitrogen (and consequently corresponding shoot and leaf stimulation), only 40% as much fertilizer needs to be bought and applied on lawns when applying 10-6-4 as when using 4-12-4.

Nitrogen, an essential component of leaf production, is of utmost importance in feeding lawns, as mowing is continually removing the leaves. (If lawn clippings do not smother the grass, allow them to remain on the lawn and return needed food and organic matter to the soil.)

Years ago the United States Golf Association Green Section, analyzed grass clippings from specific lawn areas. They found as much as 5 pounds of nitrogen can be removed annually in clippings from 1,000 square feet of turf grass.

The same clippings removed only 2 pounds of phosphoric acid and 1 pound of potash. Also, when nitrogen is in a water soluble form available to plants, it washes out easily from the soil.

Consequently, it has little hold-over effect from one year to the next.

Learn about Balanced 10-10-10 Fertilizer

Two Important Plant & Nitrogen Relationship

Two significant relationships exist between plants and nitrogen. Understanding them may help your planning of more effective and economical lawn fertility program.

First, although nitrogen is essential to good leaf production when added to soils in large amounts, it delays or even prevents flower and fruit production.

This is highly desirable on a lawn but certainly not in the rose garden or corn patch. Therefore, fertilizers for flowers and most vegetable crops carefully avoid an excess of nitrogen.

They are high instead in phosphoric acid, which stimulates flower and fruit production as well as good root growth.

The second significant nitrogen-plant relationship is that nitrogen is available to plants in two water-soluble forms: nitrates (NO3) and ammonia (NH3).

Many crop plants and white clover, as well as most lawn weeds, prefer nitrates, but grass plants thrive on ammonia nitrogen like ammonium nitrate.

Therefore, by applying fertilizer in which at least part of the nitrogen is in the form of ammonia, it is possible to feed the grass and discourage the weeds. But such a program also discourages clover.

So should you want white clover in your lawn, you may have to reseed the clover occasionally if you use ammonia nitrogen over a period of years.

Phosphorus – Second Element In Plant Food

Phosphorus fertilizer, the second element in plant food formulas, grass needs to make good root growth.

Phosphates do not leach out of the soil as does fertilizer nitrogen. On the contrary, at the first point of contact with the soil.

Phosphates are likely to be “fixed” as relatively insoluble calcium, magnesium or iron phosphates by chemical reactions with other salts of these elements. Therefore, a relatively small amount of phosphate applied annually in a fertilizer is usually sufficient to promote excellent grass growth.

Potassium – 3rd Element in Chemical Fertilizers

Potassium (Potash), the third element in chemical fertilizers, is necessary for all plant growth processes.

It is present in most soils, except very sandy ones, in quantities adequate for growth of grass. Therefore, only small amounts of potash, if any, need be present in your fertilizer.

Use A Complete Fertilizer

For most lawns, the best lawn fertilizer applications use what’s called a “Complete Fertilizer.”

A “complete lawn fertilizer” contains all of the 3 major nutrients as discussed above: nitrogen, phosphorus and potassium and displayed as percentages like 12-6-8.

Generally speaking, look for a lawn fertilizer with a 3-1-2 ratio. Grass type, soil conditions, climate, and type of nutrient applied plays a factor. Use the ratio as a “recommendation,” do not get upset if the ratio is not exact.

You may find 4-1-2 ratio like 16-4-8, which would be fine. Remember, nitrogen leaches out faster than the other nutrients – phosphate and potassium. For this reason you will often find nitrogen at 3 to 5 times more than phosphorus and 2 times as much as potassium.

Make Fertilizer Application Before Maximum Growth Season

Making use of these facts and principles, all lawns should be fed preferably with a high-nitrogen fertilizer at the season when grass plants are about to make maximum growth.

In sections where bluegrass, fescues and bent grasses predominate, feed lawns in late summer (before the September equinoctial storms).

These grasses grow best with cool nights and warm days – in spring and fall. Late-summer, early fall applications are generally better than late spring ones, as summer annual weeds and weedy grasses, such as crabgrass, die with the first frost.

This gives well-fed grass all fall and spring to produce a turf sufficiently dense to resist reinvasion the next May by the summer weed annuals. (Exception: In the North, lush autumn growth should not be encouraged by fall fertilizing if trouble is to be expected from snow mold.)

Fertilize Kentucky bluegrass, fescues and bent grass in late winter while the ground is still frozen and you can walk on the the lawn without injury.

This application makes food available for early spring growth during the first warm days.

Fertilizer applied later in spring, however, merely feeds crabgrass and annual weeds, which are all too prone to take over when the turf grasses become semi-dormant during hot summer weather.

Avoid spring feeding of lawns where crabgrass is a problem.

However. in southern states, where Bermuda grass, zoysiaSt Augustine lawns, centipede grass and other subtropical grasses make up the lawn, spring is the time to fertilize.

These grasses make their maximum grow season – hot weather – feed the grass just prior to that new upsurge of growth.

If you overseed in fall with ryegrass for a green winter cover (as may be done with Bermuda grass lawns), apply fertilize along with the ryegrass seed.

We’ve already established the fact that a high-in-nitrogen commercial fertilizer (also true, of course, of organics) is best for lawns. But how much should you use and what about the various grades?

We’ve already established the fact that a high-in-nitrogen commercial fertilizer (also true, of course, of organics) is best for lawns. But how much should you use and what about the various grades?

Feed at least 2 pounds of nitrogen to each 1,000 sq ft of lawn each year, not more than 1 pound in one application. This would mean 20 pounds of a 10-6-4 mixture, 40 pounds of 5-10-5 or 50 pounds of a 4-12-4 grade.

If you use one of the newer high-analysis slow release soluble fertilizers, you’ll of course need to use substantially less, depending on the nitrogen content.

In any case, follow the manufacturer’s directions carefully, and the amount applied at any one time should never be greater than the labeled directions call for.


More On When To Fertilize Your Lawn

TV ads and a fast visit to a garden center in early spring will remind any homeowner – it is time to feed the lawn, the the lawn care program started!

Fertilizing the lawn allows the turf to get a jump-start on weeds, and insects before the demanding summertime heat comes a calling. If your grass is more of a cool-season grass, the lawn may stay green but not grow, during the summer the grass basically goes dormant.

The correct lawn feeding program, right amounts of the right kind of lawn fertilizer, applied regularly at the right time over a period of time can produce lawn renovation miracles.

It gives maximum encouragement to the permanent grasses in your lawn and maximum discouragement to weeds.

Such a lawn fertilization program is particularly effective when accompanied by attention to lawn soil aeration, surface and subsurface drainage, deep subsurface feeding of shade trees and proper year-round maintenance practices (lawn mowing, lawn watering, weed-killing, rolling, etc.).

Feeding Cool-Season Grasses

For cool season grasses, the best time to apply fertilizer is during the early fall. This will provide food for the grass to stay green and grow longer into the late fall cool season.

The grass may not grow much on top but in the soil the root growth can help store up food during the winter and have this food ready for a quick start when the warmer spring temperatures begin to hit.

Feeding Warm-Season Grasses

Warm season grasses come alive almost overnight when spring weather rolls around and hit their prime during mid-summer growing season. At the first sign of the turf starting to green in the spring – give it a good shot of lawn fertilizer by applying a fast-acting nitrogen source. This application makes the lawn green up faster.

Warm season grasses can also gain some benefit of a fall fertilizer application. However, if the yard is not healthy it can give a good feeding to winter weeds. If done too late in the year, cold weather can damage the soft, lush growth. Review the health of your lawn first, then consider fall fertilizing.


How To Apply Fertilizer

When applying fertilizer there are four basic methods:

  • Liquid Fertilizer
  • Spreading Solid Fertilizer by Hand
  • Broadcast Spreader – Hand or Push-Type
  • Drop Spreader

Liquid Fertilizer

Liquid fertilizing has been around for decades. It’s growing in popularity as a simple way to apply with an attached hand-held hose-end sprayer.

Liquid feeding is great for houseplants and flowers, liquid lawn fertilizer can also give quick green to a lawn but the practice does have some downsides when used to fertilize the lawn.

Applying fertilizer evenly is hard to do. The nutrients only hit the surface and do not build the grass as well. Without proper mixing fertilizer can easily burn the grass. Finally, since it acts quickly, fertilizing requires multiple applications which takes lots of time.

Spreading Solid Fertilizer by Hand

For small areas broadcasting fertilizer by reaching in a bucket or bag and “throwing” the fertilizer can be done but in general – not recommended. It is very difficult to get an even distribution. Use this method when no other options exist.

Broadcast Spreader – Hand or Push-Type

For dry fertilizer a broadcast spreader makes easy work of applying and feeding the lawn. The broadcast spreader drops the dry food onto a hopper with whirling wheel which “throws” the fertilizer pellets. The throwing action usually requires several passes for even coverage.

For example, to get even coverage, the first application would be north and south and the next pass would be east and west. Overlaping gives the best coverage.

There are two types of broadcast spreaders, a hand-held (excellent for small lawns) and a push-type, great for large lawns.

Drop Spreader

Drop fertilizer spreaders have been in use for many years, but the broadcast spreader is more popular today. The drop spreader does exactly what the name implies – it drops the fertilizer.

Each pass must overlap just enough so dark uneven green strips do not show where the excess fertilizer is applied. Drop spreaders require more passes to apply the same amount of fertilizer compared to a broadcast spreader.

Fertilizer Application Tips

  • Check and adjust the setting on drop and broadcast fertilizer spreaders that correspond to the rates of application on the fertilizer bag.
  • When applying walk a normal speed
  • Always shut off the spreader when stopping, turning around or changing directions.
  • To avoid corrosion after application always wash or brush the spreader off and allow spreader to dry thoroughly.
  • When applying dry fertilizer, it is always good to wash the fertilizer off the leaves by turning on the sprinkler or irrigation system.

5 Tips To Remember When Applying Lawn Fertilizers


Summary: When applying lawn fertilizer there are a few rules a homeowner should follow for success in their efforts. Below are 5 tips to help when fertilizing your lawn.

  • 1- Never distribute At Any One Time more than 1 pound of nitrogen to 1,000 square Feet of lawn.
  • 2 – Distribute the lawn fertilizer only when lawn foliage is dry. Leaves wet with a thin film of dew will hold the fertilizer and may suffer a serious burn as a result. After applying the fertilizer, water the lawn thoroughly if this is possible. This washes the fertilizer off of all foliage and into the ground, where it becomes available at once to the roots. Immediately before an afternoon shower is an excellent time to fertilize.
  • 3 – For uniform distribution on small lawn areas or where a lawn fertilizer spreader is not available or will not work, divide the total amount to be applied in half. Distribute half walking north and south and the other half walking east and west.
  • 4 – For uniform distribution on an irregularly-shaped lawn area, block off a 10-foot square area and apply one-tenth of the amount needed for 1,000 square feet according to method described above. Then proceed to apply corresponding amounts to remainder of area.
  • 5 – If you apply hydrated lime (not recommended) to your lawn before fertilizing, be sure to allow at least two weeks to elapse between applications of fertilizer and lime. Otherwise you may get a chemical reaction between the lime and the inorganic carriers of nitrogen, losing your nitrogen as a gas into the air and burning your grass.

Chemical Lawn Fertilizer Versus Organic Lawn Fertilizer

The advantages of the organic fertilizer are that the risk of burning the grass is much less than with inorganic (chemical fertilizers ) forms and the nitrogen does not leach away from the soil so rapidly.

The disadvantage of organics is that the nitrogen is not available to the plants immediately upon distribution of fertilizer as is the case when inorganics are used. Organic fertilizers cannot stimulate the grass as rapidly to take advantage of seasonal growing conditions.

If an inorganic fertilizer is your choice, be sure to follow the directions and application rates on the bag.

Final words of advice: Never sow seed (either on a few bare spots or over an entire lawn) without also applying fertilizer. Remember, fertilizer is as important as seed in maintaining established lawns.

JOIN Our FREE Plant Care Newsletter 

By entering your email address you agree to receive a daily email newsletter from Plant Care Today. We'll respect your privacy and unsubscribe at any time.