Category Archives: Feeding Lawns


By   October 19, 2015

Mulching is feeding and it’s one of the most beneficial things that you can do for your lawn (and gardens too, we’ll cover gardens later). Lawngrass roots soak up moisture and nutrients for growth. The moisture is easy to replace by watering, but the nutrients are either native to the soil or provided by fertilizer. If you rake or bag up your lawn clippings, these nutrients are lost. Mulch them back into the lawn and the nutrients are recycled.

Mulching mower underside

Mulching mower underside

It’s estimated that mulching can reduce your need for feeding up to 30%. And it’s easy to do, probably a lot easier than raking or bagging. Grass clippings work their way down to the soil layer where, with adequate moisture, they are quickly reduced to mulch by native bacteria and fungi. If you’re lucky enough to have a healthy earthworm population, they’ll help spread the remaining mulch throughout your topsoil layers. This is a double plus as the mixed in mulch will loosen hard caked soils and help retain water.

Earthworm in grass

Earthworms are nature’s mulchers

Earthworms are present in just about any healthy lawn or garden area that hasn’t been treated with harsh chemicals. Although most pesticides don’t outright kill earthworms, many can decrease the population as they reduce general health and reproduction. High nitrogen fertilizers fall into the same category, which is why I recommend half strength fertilizer applications and avoiding most lawn treatment companies.

Most power mowers have mulcher attachments. These usually include special chopper blades and plates that cover the discharge chute. Grass clippings are chewed up to small pieces that easily sift down to the lower levels of the grass.

Some may confuse mulched grass with thatch. Thatch is when the living parts of grass plants build up too thick. Then these extra stems, roots, and leaves weave themselves into a mat that blocks our air, water, and nutrients. Thatch doesn’t break down as it’s still alive. Mulch is dead and will break down easily.

When not to mulch:

There are a few situations where mulching may not be beneficial.  If your lawn is diseased, it’s best to rake up and dispose of the clippings to prevent the spread of the disease.  The same after fungicide applications.  Mulching after fungicide application may not only spread the fungus, but the fungicide might prevent clippings from composting to mulch.

It’s also difficult to mulch lawn clippings when it’s cut wet or heavily overgrown. Mulched grass clippings tend to stick together in clumps and look terrible.  If too thick, these clumps can block out sun and water from the grass below.  If you have a lot of these clumps, try letting them dry for a while and then running the mower over them again.  It’s time to get out the rake or bagger if that doesn’t work.  Then, as long as you haven’t used weed killer or harsh chemicals, use it to mulch your gardens.


By   October 13, 2015

Fertilizer components are labeled on the package with a 3 number series indicating the percentage of Nitrogen, Potassium, and Phosphate (abbreviated N-P-K) that is contained by weight. So a 10 pound bag of 20-5-5 contains 2 pounds 10 pounds x 20%) of Nitrogen, and ½ pound each of Phosphate and Potassium. Note that this only adds up to 3 pounds, the rest is just mixed stone dust or salt.

Pre 1900 ad for bonemeal fertilizer

Pre 1900 ad for bonemeal fertilizer

You might notice that some of the newer fertilizer bags are a lot lighter than they used to be. Manufacturers refine out more of this stone and miscellaneous junk, then mix the nutrients with a light weight filler to help it spread better. This cuts down the shipping costs and makes it easier to spread. It also makes it possible to make the fertilizer much more concentrated, but this carries some bad along with the good.

Too much Nitrogen at once can harm your lawn…that’s what happens when grass dies in spots burn from animals pee or that get too much fertilizer at once. At the same time, Nitrogen dissolves in water and can be washed away by rain, so the fertilizer manufacturers created a timed release form of Nitrogen. It adds to the cost, but is well worth the added expense. Look for the label to say that some of the Nitrogen is insoluble or timed release.

Analysis panel from Homestead Bonemeal

Analysis panel from Homestead Bonemeal

Phosphate and Potassium are rock products, so by nature they are slow release and don’t easily wash away, but they are natural salts and too much can dry out and burn any type of plants.

We’ll talk about how much to use on another page, but my proofreader wants me to mention trace elements. All living things need an assortment of minerals, everything from Iron to Magnesium, and Sodium to Copper. I get my trace minerals every day from a vitamin tablet, but your lawn can probably get all that it needs from unsupplemented soil and it’s not a serious concern.

These illustrations are from a pre 1900 publication.  Bonemeal has long been used as a fertilizer.  As the name implies, its made from crushed bones.  Bonemeal is more suited for gardens than lawns.  The most common lawn fertilizer from that time was manure.  It was sometimes spread manually on lawns, but more often it was left naturally as animals grazed.


By   October 12, 2015

For most US lawns, the most beneficial additive that can be applied isn’t fertilizer, it’s lime. Most homeowners know that it’s needed, but few know the importance of when, why, and how much.

Global variation in soil pH.

Global variation in soil pH. Red = acidic soil. Yellow = neutral soil. Blue = alkaline soil. Black = no data. Chart by Ninjatacoshell (Own work) [CC BY-SA 3.0 or GFDL], via Wikimedia Commons

As you can see from the chart, just about all of the regions in the US where grass is commonly grown are natively acidic.  The blue areas are mostly arid desert and we can’t use the term “easy lawns” there.

Lime is applied to the soil to increase the soil pH. pH, a measure of the soil’s acidity or alkalinity, and can directly influence the vigor and quality of the home lawn. When the pH is below 7.0, the soil is said to be acidic; when above 7.0, it is alkaline.

When the pH drops below 6.0, the chemical reactions that supply some of the lawn’s nutrients can’t happen. It’s a form of malnutrition, the food might be there, but your lawn just can’t use it. Low pH limits your lawn’s ability to use nitrogen, phosphorus, potassium, sulfur, calcium, magnesium and molybdenum is restricted. The result is that your good looking fine grass’ growth is stunted and less desirable varieties or weeds or moss are able to take over.

Overly high pH can be just as bad. Alkali soil over pH 8.0 limits your lawns ability to use nitrogen, phosphorus, iron, manganese, boron, copper and zinc. Either way, too high or too low, and your lawn will start to show a loss of color, vigor, and tolerance for drought, heat, and stress.

Most soils tend to be acidic. Heavy rainfall and long time cultivation, combined with the type of soils left behind by the ice age, tend to leach the neutralizing minerals out of the ground. Of course, acid rain doesn’t help, and decomposing leaves add to the acid levels.

Fortunately, acidic soil is easy and moderately inexpensive to fix. Limestone is  very common and it acts just like a giant Tums tablet when it’s applied to your law. It neutralizes acid and provides calcium and trace minerals at the same time.

Before you start, a soil test can tell you how much you will need. Don’t be surprised, it’s going to seem like a lot, but lime is inexpensive and, aside from carrying it home, it goes on easily. Your test will indicate how many pounds of pure calcium carbonate you will need per 1000 square feet. Since different types of limestone have slightly different contents, you’ll have to do a simple calculation. Use the table at the bottom of the page to determine how much you will need.

Lime can go on any time of the year when the ground isn’t frozen or the grass isn’t parched or wilted. It’s a good idea to water after application to wash it off the grass blades and before it blows away.


Lime Materials And Their Characteristics 

Material Calcium carbonate equivalent Rate of pH change Max. recommended rate of application Other comments
Burned Lime 180 Fast 10 Hazardous, difficult to apply
Dolomitic Limestone 70-95 Slow 50 Also a source of magnesium
Ground limestone 70-95 Slow 50
Hydrated Lime 140 Fast 20 Hazardous, difficult to apply
Pelletized Limestone 70-95 Fast 50 Easy to apply, more expensive than other sources

All values are approximate and vary by product.

How Often to Fertilize

By   October 8, 2015

Now for the secret formula…how often to fertilize. The answer is simple and not what you would expect. The amount that you need is…just enough and not more!

Professional landscapers have charts that measure the optimum amount of each nutrient for each type of soil condition and grass species. The results are spectacular. Grass grows lush, full, and bright green. At the same time, it may need to be cut 2 or 3 times a week and the forced growth makes it highly susceptible to bugs, lawn diseases, and errors.

For our easy lawn care, we’re going to modify our how often to fertilize schedule by the 60% rule. We’re going to lighten way up on the feedings, cutting our fertilizer usage way down from the professional care level, reducing cutting and maintenance substantially, and ending up with a healthier lawn.

For most lawns, 2 or 3 feedings a year are enough, but the timing will surprise you.

  • If you can only feed your lawn once a year, use a good quality lawn fertilizer around Labor Day. Fall is the best growing season, and an application at this time will help the grass strengthen and the roots grow right up until the ground freezes.

  • A second feeding in the Spring will help your lawn green up earlier. This is also a good time to apply a pre-emergent weed and crabgrass preventer. This is covered in more detail later, a pre-emergent stops weed seeds from growing.

Timing two feedings this way will keep your grass growing and healthy through most of the growing season and allow your lawn to rest a bit during the stressful summer dry times.

The next step up on the lawn care ladder adds another feeding late Fall, just about Halloween. Once again, use a high quality fertilizer made for Fall use. Fall fertilizer generally has a bit less Nitrogen and more Potassium and Phosphate for less top growth and more root growth.

Unless you have an automatic watering system, avoid late Spring feedings. Your grass needs water to live and forcing growth with fertilizer might result in depleting the plant’s stores and weakening or killing your grass.

Soil Ph

By   October 8, 2015

Inexpensive soil testing kits are available at most garden shops and state agricultural extension offices. Theoretically, they can tell you exactly how much of each nutrient that you need to add and when to add it.

Even without a test, I can tell you with 95% certainty what you need here in the Northeast. Since Nitrogen is water soluble and gets consumed quickly in a lawn, chances are very high that unless you have fertilized in the last few weeks, your lawn needs lots of Nitrogen. Phosphate and Potassium don’t get used up as quickly, but established lawns have usually used up most of the supply.

Ph is Important

The test that is important, though, is pH. Here’s where you get to throw around technical terms and act like a scientist. pH is an abbreviation for the potential of hydrogen, or simply a measurement of the amount of acidity or alkalinity in a substance. It’s important because everything that goes on inside the cells of grass plants is chemistry based, and some chemicals just don’t work right if things don’t have the right amount of acid.

Without getting too technical, pH is measured from 0 to 14, with 0 being the ultimate alkaline level, 14 is the strongest acid, and neutral is in the middle at 7. Not surprisingly, grass likes it best around soil Ph of 7.

Here in New England, our combination of soil type, water, and our types of trees make everything acid. Fortunately, there’s an easy and inexpensive way to fix your soil’s pH. It’s the equivalent of giving your lawn a big Tums…ground up Limestone is available from most garden shops and discount stores. It goes on easily, starts working quickly, and lasts a long time.

The bad news is that it sometimes takes a lot of limestone to correct neglected soil, it may take a while to penetrate down to the lower levels of your lawn’s roots, and needs to be reapplied every few years.

Limestone is generally available in two forms, ground to a powder and pelletized. The ground limestone is the least expensive and, up until a few years ago, was the most popular. It’s a fine powder and needs to be applied with a drop-type spreader. Many a gardener has found that, as they work up a sweat pushing the spreader, the fine powder that blows around sticks to their moist skin and they end up looking something like Casper the ghost.

Pelletized limestone eliminates this problem. It’s formed into small pellets that spread easier, don’t blow around, and can be applied much quicker with a broadcast spreader.

An important note…limestone is generally safe. After all, it’s added to food as a source of calcium, but it’s never good to expose your skin to large amounts of the low pH material, and getting the dust in your eyes or nose can cause irritation.

High Ph

It’s unusual but some in some locations the soil might be too alkaline, the opposite problem that most of us face.  It’s unusual in the major grass growing zones, so if you soil tests as heavily alkaline retest to be sure.  Some plants and shrubs like their Ph to be heavily acid.  Blueberries are the most common acid lovers although many of the evergreen foundation plants will prefer slight acid.  Hydrangeas will tell you if they need more acid.  Above Ph 5.5 soil Ph or so and their flowers will be pink, below 5.5 and the flowers are blue. Aluminum sulfate is the most common chemical used to bring the Soil Ph down.

Soil Testing

By   October 8, 2015

Soil testing is an inexpensive service that can save a lot of time, trouble, and money. Primarily designed for farmers, your lawn can benefit from the same professional analysis. For just a few dollars, a test lab can tell you exactly what’s missing from your soil and take the guesswork out.

Soil Testing Kits

Reports vary, but most soil testing results will include:

  • A pH measurement. Soil pH is a measure of how acidic or alkaline your soil is, which affects nutrient availability. The pH scale ranges from 0 to 14, with 7 as neutral. Numbers less than 7 indicate an acid condition, while numbers greater than 7 indicate an alkaline soil. Most grasses like the pH to be close to neutral, but New England soils, ran, and native plants tend to push the pH towards the acid range.
  • Primary nutrients. These are the N, P, K basics that are listed on the fertilizer bag. N, P, and K stands for Nitrogen (N), phosphorus (P) and potassium (K) which are needed in fairly large quantities compared to the other nutrients.
    Secondary nutrients: Calcium (Ca), magnesium (Mg) and sulfur (S) are secondary nutrients which are required by grass in lesser quantities than the primary nutrients. Zinc (Zn) and manganese (Mn) are micronutrients which are required by plants in very small amounts.
Typical soil testing kit

Typical soil testing kit

For a good soil testing, you need to take a good sample….the test won’t be accurate if you happen to pick a spot that your dog watered last night. Using a trowel, take 4” deep slices or cores from 6 to 10 locations. To get a good sample, mix several samples from different location together in a clean bucket or sample bag (plastic, not paper). Make sure that everything is super-clean, and don’t use your hands.

For lawns, the most important test is pH. If you get the pH in to the recommended range, existing nutrients from the soil will become available to you lawn and your primary nutrients will be much more effective. Lawns are heavy feeders, so expect your test to almost always show deficiencies of the basic N, P, K nutrients.