Category Archives: Fertilizer

Proper Liming of Turf

Hi Folks.

I get many questions about the proper Liming of a lawn all the time. The questions vary, but these are often the most popular.

Should I lime my yard?

How often should I lime my lawn?

How much Lime should I put down?

Whats the difference between powdered lime and pellets?

When is the best time to lime?

Will lime kill moss? (I answered that one in my last post)

I have found 2 links to answer these questions . I will add some finer points to liming later, but these links should answer most of you questions.

12 questions about liming from Ohio state

more detailed Liming information from Ontario Ag dept.

One last thing. From these articles, you will understand that all lime isn’t equal. The magic number is usually the CCE (calcium carbonate equivelent) .

CCE of 100 means that the lime you are buying potent lime. It is a measure of against pure calcium carbonate.

The less the CCE, the less liming power the lime has. You will then need more lime to do the same job. Its not that lower CCE liming materials are bad, they just will require more. I have seen Lime sold at Big Box retailers with a CCE as low as 48%. It will take you twice as much of this lime to what a 100% Lime material will do.

Spend you money wisely. Sometimes the 3 for 11.95 deal at the garden center isn’t such a good deal after all.

In my next post, I will detail how to calculate these numbers if you are applying lime from a soil test recommendation. Happy Liming

Basic Fertilizer Math

I have been asked to recommend a good fertilizer for late fall (for example) in New England . I suggested a product 32-3-6 with 30%CRN 2%FE . I was told “I don’t want to use that high of a number in the Fall”

What he was referring to is the 32 . The nitrogen. I then realized how many people don’t understand some basic fertilizer math . I know it because I use it daily, but others may not. Some may be basic, so bear with me if you know this stuff. So, here goes….

32-3-6 what’s that? Those 3 numbers on a fertilizer bag represent N-P-K.
Nitrogen , Phosphorous, and Potassium. N-P-K …

Each number represents the percentage of the contents of the bag.

N = 32% of the contents
P = 3% of the contents
K= 6% of the content

The rest is micro nutrients and fillers. From here on out I will use N,P & K to represent each nutrient instead of typing the whole word

In this instance it will be a 50 lb bag of 32-3-6 straight fertilizer containing:
.32 x50 =16 # N
.03 x50 = 1.5 # P
.06 x50 = 3 # K

Most commercial fertilizers and retail products have a setting for your spreader on the bag. Some will break it down for different #’s of N, but most are derived from 1# N per 1000 sq ft. That’s what most everyone is trying to achieve .

In this instance at 1#N per 1000 sq ft and 16 #s of total N in the entire bag, you will get about 16,000 sq ft from this product at the recommended rate which is usually defaulted to 1 # N per 1000 sq ft.

Most cool season grasses require about 4 lbs of N annually per 1000 sq ft. Never put it down at once!! That’s why you fertilize 4-5 times a year to replace the N that the plant uses in abundance. At about 1 lb of N per 1000 sq ft each time you fertilize, with 4 -5 fertilizer applications ,you get your annual requirement of 4lbs.

Here is the key to the whole story. This customer walked out with 20-1-5 instead of the 32-3-6. Nothing wrong with that at all, because the 20-1-5 is a fine product.

He asked how far it goes . I said 10,000 sq ft . He bought it.

The part that most people don’t realize is the recommended setting on the bag of the 20-1-5 fertilizer for his spreader was derived from 1lb N per 1000 sq ft ,so he gets 10,000 sq ft from that 50# bag.

The 32-3-6 goes down at the same 1lb N per 1000 (the exact same rate) , but he will get 16,000 sq ft from the same 50# bag as opposed to 10,000.
He didn’t want a “high number”, but is getting the same amount of Nitrogen on the lawn. As a matter of fact , the 32-3-6 was probably a better deal because what he was getting was 16,000 for a certain price, or 10,000 sq ft for a little lower price.

Combination products are a bit different. These are weed & feeds, crabgrass preventers with fertilizer, etc. Those recommended settings or rates are based on the amount of whatever active ingredient is on the fertilizer, like weed control or insecticides. In this instance , delivering the right amount of active ingredient per 1000 sq ft is more important than lbs of N per K.
Most combo products usually put down less than a lb of N per 1000 sq ft because of this. Usually 3/4 -1 lb per 1000 . This is where they get a recommended setting for these products in stead of with a straight fertilizer.

Retail products are a bit different from what I see. A bag will have 26-3-9 on it, and the bag says “covers 15,000 sq ft” . Any manufacturer can label whatever they want on a bag for coverage, but in this case if this fert is in a 50 lb bag , you probably should get about 13,000 sq ft instead of the 15,000 it claims.

One last nifty tip. As long as you are looking a 50 lb bag of fertilizer (most professional fertilizers are sold this way), you can simply take the N content (we will use 32 here ) and divide it in half for 16 . You get 16,000 sq ft at 1# N per 1000. It must be a 50lb , and it must be straight fertilizer .

If you can grasp these basic concepts, you understand more than most, even some lawncare folks

Cool Season Turf fertilizing strategies

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Most lawn grasses grown in New England — Kentucky bluegrass, perennial ryegrass and fescues — are cool-season grasses. They grow best in spring and fall.

The roots of cool-season grasses grow best between 55 F and 65 F. Shoots grow best between 67 F and 75 F. In early spring, even before the grass starts to green up, the roots break dormancy and begin growing.
The combination of long days, cool temperatures and usually adequate moisture produces a flush of growth in the spring. This sometimes makes it challenging just to keep up with mowing. In a normal year, 60 percent of grass growth comes during 6 weeks in spring.

Spring is a good time to get the lawn off to a good start, but over fertilizing a healthy lawn at this time just promotes excessive top-growth (and mowing chores) at the expense of root growth. This lush, succulent growth encouraged by early spring fertilization makes the plant more susceptible to insects and diseases. Plants with smaller roots are also more vulnerable to drought later in the season.

As temperatures warm during summer, growth slows down and lawns require mowing less frequently. This is known as summer dormancy. Roots can be damaged when temperatures are above 85 F. During this “summer slump,” warm-season weeds such as crabgrass and spurge can thrive because they are more competitive in warm weather.

The combination of warm temperatures and lack of moisture can cause cool-season grasses to go dormant and turn brown during dry summers. This is a very natural occurrence with cool season grasses. In most cases, the grasses haven’t died. They will green up and grow again in fall when cool weather returns and soil moisture is replenished.

Fall is the best time to fertilize lawns because the nutrients primarily support root growth. They help the plants build up reserves to get through the winter and green up in spring.

An ideal time to apply your last application, (commonly called a winterizer application) is about 2 weeks after your last mowing when the lawn goes into winter dormancy. Apply 1 pound of nitrogen per 1,000 square feet. This is one of the only times I would recommend an immediately available nitrogen source (quick release nitrogen).

Don’t over fertilize, and avoid early spring applications.

Just like people, lawns need a balanced diet, too. If you feed them too much, too little or the wrong kind of fertilizer, they won’t be healthy. With lawns, when you fertilize is just as critical.

Be sure to test your soil and adjust pH, if needed. Lawns should have a slightly acid pH, between 6.0 and 7.0. If your soil tests fall outside of this range, follow instructions for adding lime or sulfur to bring pH into this range. Rarely will you have to apply sulfur in New England as soils tend to be acidic.

Focus on fall. If phosphorus and potassium levels are adequate in the soil, nitrogen (N) is the most important nutrient for grass growth. Understanding how grass grows is important when making decisions about how much and when to apply nitrogen fertilizer.

For lawns properly fertilized the previous fall, a full application of fertilizer (1# N per 1000 sq ft) can sometimes be put off as late as Memorial Day.

Research shows that early spring applications do not really enhance spring green-up compared with late-fall applications, and the risk for later problems like disease, is far greater.

Applying a low analysis organic fertilizer, or a product like Solu-cal is a much better choice in the spring. Neither will promote excess top-growth (or clippings), and both will greatly benefit the turf and the soil. Using these products in early spring will actually help reduce summer stress and disease pressure later on.

At least 50-60 percent of the nitrogen applied to New England lawns should come between the middle of August and November for healthy green turf in spring.

Lawns that did not receive fall fertilizer applications or have suffered from winter injury may benefit from earlier spring nitrogen applications. But wait until soil temperatures have warmed to at least 55 F before applying.

Water it in. Water your lawn with a quarter to a half inch after spreading fertilizer to get the material into the ground where it can be used by plants.

Consider the source. If you are using synthetic lawn fertilizers throughout the season, use products that contain at least 40% total slow-release nitrogen. Slow-release N becomes available to the plant over a period of time depending on soil moisture, temperature and microbial activity.

Their are many different slow release N choices. The cheapest (and least consistent) is Sulfur coated urea or SCU. Other types (and more predictable) are polymers, methylene ureas and IBDU . These types tend to last longer and release more predictably. The balance of the Nitrogen in the bag is water soluble nitrogen, which is readily available for plant uptake.

In addition to supplying N over a longer period of time, slow-release nitrogen sources have a lower risk of burning plants and a lower potential to leach out of the soil. The tradeoff is that higher quality slow-release N is usually a little more expensive. The few extra pennies up front will save you much more later on. Don’t trip over a dollar, trying to save a nickel.

Natural organic fertilizers supply nitrogen in complex organic forms that are not immediately available to plants. Most require warm, moist soils for microbial activity to release the N over a period of time. Natural organic fertilizers are well-suited for applications during warm summer months when the potential for burning plants with higher-salt synthetic fertilizers is higher.

Lawns grown on mostly sandy soils should rely more on higher quality slow-release nitrogen to reduce the possibility of N leaching out of the root zone. Incorporating high quality organic fertilizers not only provides the turf essential nutrients, but the soil also. If you fertilize with a “ground up” approach, the turf will benefit greatly.

Consider different needs. High-traffic areas usually require more fertilizer than low-traffic areas. Different species of grass have different needs, too. Kentucky bluegrass, for example, requires more nitrogen than fine leaf fescues.

If bluegrass doesn’t get enough N, it is less competitive against weeds and pests. If fine leaf fescues (which normally grow slowly) get too much N, they produce lush, weak growth that is susceptible to pests.

Apply with care. The whole idea is to get the right product on the lawn at the right time. Lawn care is all about timing. I can probably be more successful using low quality products at the right time, than using the highest quality products at the wrong time. Neither is an ideal situation and should be avoided. If you can scrape by using low quality fertilizers at the right time, imagine what can happen when you use high quality products.