A quick stroll down the fertilizer aisle at any hardware store is likely to lead to some confusion: synthetic or organic? Liquid or granular? 20-20-20, 5-10-10, 10-5-5, or 5-8-7?
If you have no idea what any of this means, then you’re in the right spot!
Before we dig into what fertilizer may best suit your lawn, let’s first take a peek at the three most common components of fertilizer. These components represent the fertilizer’s NPK breakdown, which contribute to the health of your lawn in various ways:
- N – Nitrogen – promotes stem and leaf growth and is also responsible for that deep green color.
- P – Phosphorus – is linked to the plants photosynthesis process and encourages healthy root growth.
- K- Potassium – encourages plants’ disease resistance.
While you can eyeball what your grass needs and choose a fertilizer product based on appearance, the safest and most effective course of action is to do a quick soil test to determine what specifically your soil needs. Soil tests have improved drastically over the last decade or so, and for between $10-40, you can get a fairly reliable testing kit that will tell you the nutrient makeup of your lawn and exactly what it needs. In a nutshell, a testing kit will tell you whether your lawn has either depleted, deficient, adequate, sufficient, or a surplus of nitrogen, phosphorus, or potassium.
Synthetic v. Organic
These are very loaded words these days. You might read them and think, “Of course, organic is better.” And you would not be wrong to think that. While organic fertilizer may be preferable if you’re looking to limit certain chemicals (specifically if you plan to eat your plants), organic may not be the most effective.
A lot of it has to do with what you’re growing and what stage of growth it’s in. As a general rule of thumb:
- Synthetic fertilizer is cheaper and will feed plants fast. A pitfall of synthetic, is, well, it’s synthetic. Some chemicals contained in synthetic blends can adversely affect water runoff.
- Organic fertilizer is a little pricier and will feed plants slowly. Organic, as you can imagine, doesn’t harm the environment, and improves the nutrient makeup and structure of the soil—but this takes time.
But you don’t have to feel like you need to pick one or the other. In fact, it’s actually best to have both on deck, depending on what you’re trying to grow. Let’s take a peek at a couple of quick examples.
- Plants in containers: This is a good example where synthetic usually triumphs over organic. Because you’ll likely be less concerned with improving the soil structure and more concerned with the growth of the plant in the short term, synthetic is a good choice for this use case.
- Trees: While you probably don’t need to fertilize the big, productive trees on your property, you may want to fertilize the younger and smaller ones—which is a solid use case for organic, provided the tree is currently healthy. Organic fertilizers often take years (seriously) for the nutrients to completely work their way into the soil, and trees will benefit from this slow absorption much more than, say, a tomato plant getting ready to blossom.
- Veggie garden: If you just planted a vegetable garden for the first time this year you may actually benefit from using both synthetic and organic fertilizer. Organic fertilizer will help contribute to building a healthy soil structure over the long term, whereas synthetic will help contribute to a successful crop this year.
Granular v. Liquid
These words are far less triggering than synthetic and organic. Ah. I finally feel like I can breathe.
- Granular: Because it disintegrates and works its nutrients into the soil over time, granular is what you might call “slow release.” While it’s usually easier to spread over large areas thanks to fertilizer spreaders, it’s often a little trickier to apply to things like potted plants.
- Liquid: As you may have guessed, liquid fertilizer works itself into the soil much quicker than granular seeing as though it doesn’t have to break down. With liquid, however, since it’s difficult to know what you’ve sprayed and what you haven’t, it often leads to uneven coverage (which may mean some plants don’t get fertilized at all.
Hopefully, these tidbits will make the world of fertilizer feel a little less cumbersome. While there can be a good amount of variation, if you use this knowledge and the instructions on the back of the fertilizer bag, you should be in good shape.