Fertilizer is defined as any organic or chemical substance that, when applied to the soil or plant foliage, provides nutrients to enhance plant health and productivity.  Both organic and chemical fertilizers provide NPK, i.e., nitrogen, phosphorus, and potassium, the three macronutrients all plants need.  But there are differences between the two types of fertilizer.  In this post, we will learn what those differences are, the advantages or disadvantages of each, and which one is ultimately better.

Organic Fertilizers

Organic fertilizer, also referred to as natural fertilizer, comes from natural sources such as bone meal, animal manure, blood meal, plant waste, fish emulsion, and other living or once-living organisms.  It requires less energy to produce organic fertilizer, so it is more energy efficient to make than chemical fertilizer.  

One of the most important aspects of organic fertilizer is that it works with microbes in the soil to break down the nutrients so plants can utilize them.  Instead of harming the microorganism that improve soil structure and fertility, organic fertilizer benefits the all-important soil web.

Organic fertilizers are not water-soluble, thus, the nutrients are released more slowly. As a result, you may have to add organic granular fertilizer to your soil in advance of when it is needed.

You may notice that organic fertilizers usually have a lower NPK ratio than chemical ones.  In simple terms, this means that they are not as fast-acting as chemical fertilizers.  Nevertheless, they will feed the plants for a longer period of time. 

In addition to providing NPK, organic fertilizers also provided secondary macronutrients such as calcium and magnesium and micronutrients like copper and zinc.  Moreover, they also often contain probiotics, microbes, and mycorrhizae which greatly benefit the soil as well.  Unfortunately, this is usually not the case for chemical fertilizers unless the manufacturer adds organic matter to the final product.

The organic granular fertilizers that I use are Dr. Earth’s Home Grown Organic and Natural Blend and Johnny Appleseed’s Organic’s Climate Gard.  The organic liquid fertilizers I use are Neptune’s Harvest, Lilly Miller’s Alaska Fish Emulsion, and Dr. Earth’s Home Grown Organic Pump and Grow. 

Chemical Fertilizers

Chemical fertilizers, also known as synthetic fertilizers, are used by gardeners, farmers, and large-scale agricultural operations worldwide.  Like organic fertilizers, they can be very effective in improving plant health and productivity.  Because they are water-soluble, they are more readily available to the plant.  This fast action translates into faster plant growth.  However, because they are short-lived, you will most likely have to fertilize more often than you would with an organic fertilizer. 

The ingredients found in synthetic fertilizers are made by chemically processing petroleum into compounds like ammonium nitrate, ammonium phosphate, and potassium sulfate.  These compounds are high in salts and, because they are highly water-soluble, they can leach into surface water and groundwater.  What’s more, salts can be harmful to the soil microorganisms that are necessary for making nutrients accessible to plants.  In addition, chemical fertilizers are more apt to cause plant “burn” from improper application than their natural counterpart.

Chemical fertilizers are typically less expensive than organic fertilizers, however, you may have to apply them more often, which would increase the cost.  In addition, artificially created fertilizers take more energy to produce than organically occurring ones and are, therefore, less energy efficient. 

Synthetic fertilizers often do not contain micronutrients such as copper, boron, iron, etc. found in organic fertilizers.  Thus, if you choose to use chemical fertilizers, it would be helpful to add compost to the soil to add additional nutrients, improve soil texture, and increase the beneficial microorganisms necessary for good soil health.

Organic vs Chemical Fertilizer: Which is Better?

Even though chemical fertilizers tend to be less expensive initially, and they often produce quicker results, organic fertilizers last longer, benefit the soil web, and do not add harmful salts to the soil or to the surface water or groundwater.  Overall, organic fertilizers are better for your garden and the environment.