5 Steps to a Great Lawn pt 2 Fertilize!

If a little gets you good results, then more will get you even more, right? Wrong. If you think this way, forget everything you know, because my friend, you already know nothing. Fertilizing is consistently an area where people throw everything out of whack with their good intentions but a complete and total lack of understanding of how plants work with nutrients. My neighbor uses this stuff and his lawn looks great is the mentality. Really? What kind of grass does he have? How much is he watering? Does she mow every other day? How was the soil amended before planting? Do you have the same amount of sunlight or shade? 750 varieties of bluegrass alone and counting, are you sure the lawns are the same? The monkey see monkey do way of doing things is usually a fools game, so let’s cover a few simple basics about fertilizer to help you make the best plan for YOUR turf.

N-P-K Nitrogen-Phosphorus-Potassium. These are those three numbers in great big type on the face of every bag or box of fertilizer produced. It’s known as the guaranteed analysis and it represents, by weight, the percentage of each of those elements in a given fertilizer. Those three elements are known as the primary nutrients and along with micronutrients, compose the food that all plants must have to do their thing. So let’s say you have a ten pound box of a fertilizer that shows an analysis of 24-10-8. So actual pounds of the nutrients becomes 2.4 lbs of Nitrogen(10 lbs total, X 24%) 1 lbs of Phosphorus (10 lbs total, X 10%) and .8 lbs of Potassium(10 lbs total, X 8%) in that box. Why do you care? Simple. Every plant has a known nutrient need for optimum plant health. Don’t provide enough, the plant dies. Over provide and the plant takes on undesirable characteristics (like growing a hundred miles an hour) or can be burnt down by the fertilizer. For most turf managers, N (nitrogen), is the primary concern. P & K become issues to be dealt with that are more specific to local soil conditions along with iron and the micronutrients. So why N? Nitrogen fuels vegetative growth, leaf and stem, this means the grass blade in a turf. Phosphorus stimulates bloom, fruiting and seed production, not such a big concern for grass, while Potassium helps root development, a critical function, but naturally available in most soils, therefore not necessary, under most conditions, to needing a lot of supplementing.

So let’s focus on the N for the time being and discuss what it can do for or to you. Different turf grasses have different N needs, generally ranging from 1 lb of actual N per season to 5, 6 or even 7 lbs per 1000 sq. ft. per growing season for the hungriest of turfs. Since bluegrass is far and away the most prevalent turf out there, we’ll use it as an example. It’s basic needs are 2.5 lbs of actual N per growing season. So we go out there at the start of the season and toss down that amount and we’re all set, right? No. That’s the needs for the entire season and just as we can’t sit down and eat 8 months of food at a time, neither can your plants. In fact, applying heavy loads of fert is one of the fastest ways to damage or even kill your lawn that there is. A lawn can burn out in three days doing this sort of thing to it. So we want to spread out our feedings over the season, small amounts that the plants can utilize a little at a time throughout the season. So how much and when? Well with the above example, let’s say we have an 8 month growing season and during that time, we want to put that 2.5 lbs down. If you live in an area of high temp summers and a cooler spring and fall, you will get two premium growth times when the temps are in the 60-80 degree range and you will get the best results when concentrating heavier feedings during this time. So instead of 8 equal, monthly feedings, you may want to put 30% of your fert down in the spring, 30% down in the fall and the remaining 40% spread over maintenance feedings throughout the summer. So this puts you at a .75 lbs of actual N per 1000 sq. feet for your fall and spring applications and .33 lbs. Per 1000 applications 3 times throughout the summer every month and a half or so for maintaining the minimal requirements. Another point to consider is that nitrogen is a naturally occurring element that has been provided by Mother Nature for eons, long before we got into the act. Rainfall, especially when a lot of electrical activity is present (lightning), provides atmospheric nitrogen an avenue to your plants and soil. The reason you see a brief flush of growth each time a summer storm rolls through. If a lot of rain falls in your area each summer, you may not need to supplement anywhere near as much as those in other, drier areas. Reservoir water form snow pack generally does not have the N content that summer rainfall will have due to the lack of lightning in most winter storms, so consider your water source while considering your N needs.

So how does our example compare with what you’ve been doing or been having done to your turf? Have you been over shooting the N requirements for your turf? Have you been using a lawn service that is applying 1.25-1.5 lbs 5 or 6 times per season?(6.25-9 lbs per growing season!). It’s easy to tell, combined with overwatering, your lawn may need to be mowed every three days, even in the heat. The lawn may get long and scraggly looking as the blades outstrip the roots ability to provide for the plants. Certain fungus or plant diseases and excessive thatch can be triggered by excess N, especially in humid areas. You may even see a limey/yellowing of the turf where the turf is being pushed to it’s absolute limits of leaf growth (nitrogen induced chlorosis). Why? Maintaining the turf becomes a fight, it’s not going to get the color and density you are looking for and by pushing N levels in this way, you put yourself closer and closer to the burn point. So where does higher N levels come into play? Recovering damaged turf areas or making up for poor soil or water conditions low in naturally occurring N. Even in these situations, I would not suggest exceeding 120% of the known turf variety needs.

Ratios- So now you know the role the N is playing in N-P-K and what your possible goals are for the actual lbs of that, but what about the P & K? Well, this is where local information becomes key. Knowing what your local soil is poor in is the only way to know what you’ll need to supplement. This can be done with a soil test by a qualified lab or obtained from your local soil conservancy district or university agricultural extension. Remember that soil testing is specific to your site and the other information is a bit more generalized. I would suggest the general information first then soil testing if there is a problem with what SHOULD be the proper ratios. Flat ratios, like 10-10-10, or 18-18-18 are generally for potted plant materials in small amounts and not for established turf. Your ending ratios, depending on the soil in your area, will be higher in N, low in P and possibly mid-numbers on the K. It’s not uncommon in the west to see ratios that go 8-1-2 and that would translate out into products like 32-4-8 or 24-3-6 or something along these lines. The biggest difference between products with higher or lower percentages will be the number of lbs you’ll have to apply to hit you actual N or P-K goals. If you are aiming at.72 lbs of actual N, for instance, 3 lbs of the 24 formula will get you there in an easy to measure quantity. Of course, unless you know how to blend your own fertilizer, you will be at the mercy of what is locally available, but having an idea of total, actual lbs that you are after will be critical in knowing exactly how much you want to put down at a given time.

Iron & Micronutrients- Iron is a vital mineral in plant health and in many soils, there is quite a bit naturally occurring. The problem becomes availability when soil PH gets too far beyond 7 (neutral), iron can be tied up in the soil and not available for plant use. In these cases, we must supplement iron to provide this nutrient that functions as a conduit, if you will, for all other nutrient uptake. Iron is what will be greatly responsible for dark green color as it enables the plants to efficiently utilize the rest of the primary and secondary micronutrient profile. Iron in fertilizers generally will fall in a 1-6% makeup and must be kept off cement surfaces to avoid rust staining those surfaces. Iron seems to act as the nutrient “conduit” if you will, allowing efficient uptake of other elements through the root system. You can see how a deficiency might cripple the rest of your fert program. The other elements (16 in all) include things like copper, manganese, zinc, magnesium, boron, etc. and are generally represented in trace amounts, as far as their needs in turf goes, already available in the soil. In rare cases, their can be deficiencies that need to be addressed and many fine, specialty fertilizers can be used in these cases.

Agronomy is the study of plant and soil relationships and how nutrients play a role in plant behavior. The field is ever expanding and already seemingly endless and what we know today, may be proved inaccurate tomorrow. The point of this lesson is to give you a background for tools you can use, readily available, today and what the effects are when used or misused in certain circumstances. Combine this knowledge with the other four aspects I’ll put here and soon you’ll be grabbing that sweet turf that you hardly seem to be spending any time at all maintaining, just like a pro would!