Fertilizer Basics

When it comes to fertilizers there’s a lot of sometimes confusing options and information. Make the right choice and you can eat fresh from your garden all season long. Make the wrong choice and it could hinder more than help. 

Also...what do those numbers mean on the front of the fertilizer? 

Let’s break it all down… 

What is fertilizer? 

A supplement that contains essential nutrients for desirable plant growth. 

These nutrients include Macroelements (means your plant needs more of them for growing success) and Microelements (your plant needs less of these and often microelements are found naturally in most environments that your plants will be growing anyhow). 

The three main elements (macroelements) that plants need for optimal growth are represented on the front of the fertilizer box, known as NPK, and are shown in this order: Nitrogen (in this example it is a 4), Phosphorous(6), and Potassium(2). 

So what this means is, in 100lbs of this organic fertilizer, 4lbs are nitrogen, 6lbs are phosphorous, and 2lbs are potassium. Think of it like percentages, and the rest of the mix is innocuous material that helps distribute the active ingredients. 

So, how do I choose the right one? 

Well, we think of those three numbers as “Up, Down, All-Around” so the Nitrogen (4, “up”) helps with leaf development, the Phosphorous (6, “down”) helps the roots and blooms of your plants, and the Potassium (2, “all-around”) helps with cell structure and disease/pest resistance. So, if you point to the numbers “4,6,2” it reads “up, down, all-around”. 

Example: You can see the image above of Down-To-Earth Organic fertilizer has a tomato on it and that’s because this fertilizer has a higher phosphorous content for roots and blooms (6) because we want lots of blooms on tomatoes to yield more fruit. Does this mean this only works on tomatoes? No, because this is an “all purpose” fertilizer, so it also works on any other vegetable or fruit where we want to encourage blooms. 

Example: Maybe you’re a leafy greens lover? Encouraging blooms on leafy greens isn’t the best idea, so what number would we want to be a bit higher? You got it, the nitrogen, or that first number. If you need something very high in nitrogen, City Grange also carries the Down-To-Earth Organic Blood Meal Fertilizer with a makeup of 12-0-0 so you know that you are supplementing nitrogen to encourage your spinach and lettuces to produce more leaves. 

Organic vs. Synthetic fertilizers

We encourage organic fertilizers because it means all the elements in that fertilizer were sourced naturally or from formerly living matter and will be slowly broken down by organisms in your soil to be available to your plants. That’s how most fertilizer in nature is made, from decomposing material. In fact, compost itself is a nitrogen-rich slow-release fertilizer. 

Synthetic fertilizers, on the other hand, are meant to be readily available by the plant immediately and do not need to be broken down further. This may require more frequent fertilization due to fertilizer leaching through the soil when you water. This also means if you over-fertilize your plants you run the risk of burning the roots and doing damage or otherwise throwing off the nutrient balance of the soil and possibly harming the life in the soil as well. This is where it becomes even more important to read the labels on your fertilizers and use only the amount as instructed on your fertilizer of choice. 

Neither Organic or Synthetic are necessarily better or worse for your plants, but we encourage organic fertilizers both because it’s a bit easier to control slow-release organic fertilizers and mitigating environmental risk. 

Those are the basics of fertilizer. As with anything gardening, there’s much more to learn but this should be a good start.