Fertilizing Basics - really basic

Goeie more mense!

Right, so lets talk about fertilisers. Fertilising is one of the most important parts of lawn maintenance. You need to fertilise to keep your lawns healthy. Most of you reading this have probably gone past the point of reading the label on your garden center fert and applying at that rate. You want to know more. Well, this article will tell you more but only a little. However, you need to know all of this before you can understand more, so here we go.

Most of you are aware of the common GRANULAR FERTILISERS out there. That's what you find at your local hardware store or garden center. Those little granules are called Pearls if under 2mm, and granules if between 2-4mm, for those who care. These are great for providing you with your MACRO NUTRIENTS. Some may contain SECONDARY MACRO NUTRIENTS and even MICRO NUTRIENTS and in some cases they contain other stuff that helps with the organisms in your soil too. Granular ferts are often SLOW RELEASE, which means that they slowly release the nutrients over a longer period of time than some liquid fertilisers. Granular ferts offer you a high volume of the macro nutrients vs most liquid ferts. No, that doesn't mean they're better necessarily.

You then get LIQUID FERTILISERS. Some are in a powder form so we should technically call them SOLUBLE fertilisers. These are usually in concentrated forms which you need to dilute with water before application, some are already diluted and some are soluble powders or granules. Don't try to dissolve regular GRANULAR FERTILISERS in water because you will struggle to do so in the first place and you will probably damage your sprayers.  Liquid fertilisers are perfect for when you need immediate effect from fertiliser applications or where you want to spoon feed your lawn. They are mainly quick release, however there are now many liquid ferts that are also slow release. Amazing isn't it.  

So which one do you use? Well, it essentially doesn't matter. They both feed your lawn with the required nutrients. It could also boil down to your own personal preference. For example, I prefer to spoon feed my lawn with liquid fertilisers because I then know exactly what has gone where in my yard. However, for those who want to fertilise by hand and not use any extra tools, granular fertilisers might be best for you. So, you might be thinking then that a combination of the two is then the right idea...well that's also not necessarily true. You need to read your lawn and understand what it's asking you for. And, you need to know what adding different fertiliser elements do to your lawn and how your lawn will react to them and how you can use this to your advantage.

Ideally, get a soil test done before adding fertilisers, especially if you are not sure of what to do. Email me if you need a soil test done, or if you need help understanding fertilisers. 

So lets start with what is in fertilisers?

Well, if you have ever gone shopping at your local hardware store or garden centre you would certainly have noticed that some fertilisers say that they are for lawns and some are for general garden maintenance etc. Furthermore, you would have noticed the three numbers separated by semi-colons (:) as well as another number in brackets preceding them. So it might look something like this 7:1:3 (15).

Now in the image above you see a additional bit of info afterwards. We'll get into that in a bit.
So what do these first three number mean?

      7        :           1          :        3
Nitrogen : Phosphates : Potassium
       N     :          P         :        K

These are the MACRO elements. They are the main elements that plants need to survive. They need these in larger quantities, hence the term MACRO. And, they are:

Nitrogen - This helps your lawn to grow and promotes a green lawn. Adding this to your lawn will increase growth and greening up of the plant. So its good to have lots of Nitrogen? No, too much nitrogen will cause your leaf to become too lush and plant will become easy to damage or become infected with diseases. This is besides having to fight off excessive growth.  

Phosphorus - This helps roots to establish which is vital to the success of new lawns but is also fundamental in plant growth in general. This is where most people make mistakes. You do not need a huge amount of phosphorous, just some/enough. Too much and you're inducing unnecessary growth or wasting product and you're probably adding to pollution in waterways etc. You also induce growth in areas where you may not want it, like weeds. Too much phosphorous can also hinder the plants ability to uptake nutrients and therefore kill the plant. So when you go to your local garden center and the salesman says buy 2:3:2 for your lawn, you should move on to another store. 232 is a starter fertiliser and you don't need that much phosphorous for an established lawn. Just enough for the Nitrogen and other elements to leverage off of.

Potassium - This helps your lawn to become stronger and to help it withstand various stresses. It is particularly helpful with heat and cold stresses and a main characteristic is that it builds overall strength. High-traffic areas will therefore benefit. Again, too much is not a good thing.

So what do the first three numbers on my fertiliser product mean in the order that they are shown in. Well, that's just the ratio of the amount of each of those macro elements that are in that specific formulation. The first represents N Nitrogen, the middle number represents P Phosphorus, and the last represents K Potassium.

This leads us to the numbers in brackets. In the case above it is (15). This is percentage that these macro nutrients take up out of the entire bags contents. In other words this is indicates that 15% of this bag contains purely NPK. The rest of the bag consists of other elements and process materials to complete the product. That's for the more advanced blog.

In the case above there is another number being C(18) this means that 18% of this product is Carbon. Carbon is vital to plant health and every ounce of life as we know it. SR stands for slow release.

So what does this all mean? Well, it simply means that there is a reasonable amount of Nitrogen, a small amount of Phosphorus and a moderate amount of Potassium in this mix. The added carbon in the above case simply means that the plants ability to take up these nutrients will be a little easier than products that don't contain Carbon. This does not necessarily mean that other manufacturers don't have other stuff in them that helps the plants ability to take up the nutrients easier either! Just that this one uses Carbon for that task.  

So how do I know what the weight of each of the macro nutrients in that bag are?
The formula to calculate how much of each macro nutrient you get in each bag is as follows:

Lets use the example below of another popular option in lawn care. 5:1:5(36).
5 : 1 : 5 (36)
5 + 1 + 5 = 11
(36) ÷ 11 = 3.3%
5 x 3,3% = 16,5% N (NITROGEN)
1 x 3,3% = 3,3% P (PHOSPHATES)
5 x 3,3% = 16,5% K (POTASSIUM)
So in a 50kg bag there is 8.25KG of Nitrogen, 1.65KG of Phosphates and 8.25KG of Potassium.
Makes sense, right?

You may also have noticed that somewhere along the way I chopped and changed the word 'phosphorus' to 'phosphate'. They are essentially one in the same but phosphorus is the actual element that the plants need and phosphates are a compound which the clever humans making fertilisers use to help you get phosphorus levels up in your lawn.  

What are the MICRO NUTRIENTS then?
calcium, magnesium, sulphur, manganese , Boron, Copper, Iron, Chloride, Manganese, Molybdenum, Zinc etc
Micro nutrients are called that because your lawn only needs a little of each of these, but they are all critical in your overall plant health. There are lots of other goodies in fertilisers but that for the advanced blog.

So, even I am getting tired of writing this now. Here's the short and sweet summary of how to use your fert.
Firstly, you need to know what your grass is doing and what you want it to do. If you want to increase growth, you need Nitrogen. However, Nitrogen needs Phosphate but not too much or you'll hinder the Nitrogens performance or even kill the plant.  If you are really worried that your ability to read your lawn is not great, then you need to get a soil test done to see what you have enough or too much of.

So, that's it for this one. If you came here for a short answer to your fert questions, Use a balanced fert such as 2:3:2 or 5:3:4 to establish your new lawn or as your first fert application coming out of winter. If you have an established lawn and you just want to keep it going nicely, use 4:1:2 blend and you'll be fine in most circumstances. 

Thanks for reading all of this and please don't hesitate to contact me should you have any questions.

Cheers, Trav.