Nitrogen – The “N” in the N-P-K and always the first of the three numbers.
Nitrogen is an essential macronutrient for growth, especially the vivid green that is so prized, and species such as grasses (as in your lawn) are voracious users of N, and require heavy feeding throughout the growing season. In commercially manufactured fertilizer, there generally two distinct types of Nitrogen forms.
Nitrate Form – this is the form that is most quickly absorbed and utilized by plants, but because of this ability to be rapidly absorbed, it will also be rapidly leached, or washed through the soil profile. Commonly called a “quick release form”.
Ammonium Form – this is the form that tightly attaches itself, or bonds, to the soil particles, making it much more stable and lasting. Because of this bonding, this form of N moves to the plant root system much more slowly, and serves to feed the plant over a much longer period of time. Yes, it’s also called the “slow release” form.
You actually need both forms of N to keep a lawn lush and green over a growing season, and though it’s possible to achieve this by alternating applications of each, I’ve always found it better to broadcast a blend of the two, thus feeding your grass with a quick boost from the Nitrate form, then following with a more sustained release from the Ammonium form.
Don’t get too hung up on the terms, just make sure your fertilizer is a blend of both.
Understanding The Numbers
Obviously the higher the number, the more of that component in the analysis. A “N’ form widely used in agriculture for example is 46-0-0 or in other words 46% of the weight of fertilizer is pure Nitrogen. Farmers apply “N” in pounds per acre, (or kilo’s per hectare) so they would know that 1,000 lbs of 46-0-0 would contain 460 lbs of actual N. As they always apply a specific amount of “actual N” per acre or hectare, it becomes very easy to figure out how much of the actual product to apply.
You too can make this calculation very easily once you understand the numbers…
Understanding the basics
I think the average homeowner looking for that lush green, healthy lawn really only needs to remember that the Nitrogen component is what brings on the rapid growth and the vivid green color in lawns, but it comes in two forms and you need both. Being a strong growth promoter, it can also be “hot” if you over do it and apply to much, and will actually “burn” the grass. More is better does not necessarily apply here.
Understanding the balance
All plants need a balance of all three elements, as each delivers its own unique component in the building block of growth, so let’s look at the next element, the Phosphorous or “P”…..
Read more at Understanding Lawn Fertilizer – Phosphorus