Types of Fertilizer

Different Types of Fertilizers and Their Environmental Impact

October 4, 2021  |  Annuals, Fertilizer, Lawns, Perennials
A hand sprinkles fertilizer on soil.

Fertilizers for Your Garden


Gardeners often complain that they can’t keep their plants alive or that they are cursed with the “touch of death.” 


While it is true that some plants do die despite our best efforts, the truth is that most plants meet their demise from improper soil nutrition. If you hope to avoid becoming the Grim Reaper of plants, you must make proper use of fertilizers.  


There are several different kinds of fertilizers, and each has its own purpose, effects, and drawbacks. 


In this post, we will go over the different kinds of fertilizers, and their impact on the environment.  


Controlled-Release Fertilizers 


Controlled-release fertilizers, one of the most common types of fertilizers, provide a slow and steady release of nutrients to your plants to dole out nutrients over an extended period.  

Perfect for the gardener who wants to watch the fruits of their labor without too much work!
The main benefit is that gardeners do not have to fertilize their crops as often and controlled-release fertilizers prevent nutrients like nitrogen from leaking into groundwater.  
Nitrogen leakage has an extremely negative impact on the environment, especially on marine wildlife. Nitrogen runoff is the cause of untamed algal blooms in the great lakes and the so-called “dead zone” in the Gulf of Mexico.
Controlled-release fertilizers contain 15% or more slow-release nitrogen, causing them to work for an extended period. 


Organic Fertilizers 


Organic fertilizers are materials derived from plants and animals, most commonly manure. Urine and fish emulsions are also used.  
Organic materials should be put into the soil before fertilizing then gardeners should add more after planting to yield maximum effect. After planting, fertilizer should be placed beside the row of plants, not directly around. 

Just be careful when walking through your garden afterwards that you don't pick up any manure on your shoes! 
Organic fertilizers provide quick availability of nitrogen, which is extremely important when growing vegetables.  
Gardeners can supplement organics with inorganic fertilizers for quick feeding. 
Fish emulsions are an alternative to mammal waste and are low in phosphorus and high in nitrogen. They are intended to be mixed with water and then sprinkled directly on plants every two to three weeks.  
When surveying types of manure, be sure to examine the nitrogen-phosphorus-potassium ratio. This will help you determine which type of manure is best for your plants.  
When storing your manure, you must keep it in a sealed container. If you can smell it, not only will your friends avoid coming to your house, but you are allowing important nutrients to escape into the atmosphere.

Inorganic Fertilizers 


Inorganic fertilizers are either mined from the earth or synthesized from non-organic materials.  


Nutrients are immediately available to plants for most inorganics, however, some are designed for slow release.


For larger landscapes, use a slow-release formula to allow plants to take up nutrients as they are gradually released.  


Dry Fertilizer 


Dry fertilizers are artificially produced and there are many different applications.  


When scattering in a garden, use one pound per every 100 square feet, or 100 feet of a row before planting. After planting, side-dress dry fertilizer two to three inches to the side of each plant, and one to two inches below the seed or plant row. 


Ensure that you do not apply dry fertilizer to recently watered plants but do water after your application.  


It is of great importance that you do not overuse dry fertilizers. Dry fertilizers can easily run off into groundwater with drastic environmental consequences. 


Either measure out your dry fertilizer and use the proper amount or the Knollwood Garden Center team will hunt you down. Kidding! But seriously, don't overuse this stuff, it can be very harmful for the local environment. 


Water-Soluble Fertilizer 


Water-soluble fertilizers are meant to be used for a quick boost to vegetable growth. They will come in either crystal or liquid form and can be applied as frequently as once per week.  
Water-soluble fertilizers are easy to distribute using a sprinkling can, especially for container plant growth. 
Foliar feeding is a technique used for water-soluble fertilizers where plants are sprayed with diluted liquid fertilizers. However, foliar feeding should be used more sparingly, based on the instructions from your provider. Foliar feeding can be used to provide a special boost of micronutrients like iron, manganese, or zinc.
Water-solubles are easy to use, just make sure you don't accidentally drop the crystals in your swimming pool.  

Environmental Impact 


Until the 20th-century, man-made fertilizer was non-existent, and therefore the impact of fertilizer on the environment was non-existent. However, in the early 20th-century, a method called the Haber-Bosch process allowed scientists to synthesize nitrogen and therefore make artificial fertilizers.  


Since the Haber-Bosch breakthrough, levels of man-made nitrogen levels in the environment have skyrocketed.  


Synthesized fertilizers are the worst for the environment and are especially damaging to marine life, so be careful when you use them. This isn't like IKEA furniture, you actually need to read the instructions on the package.  


Concerted conservation efforts and low tillage are important to producing nature-positive results.  


According to the Centre of Ecology and Hydrology in the United Kingdom, 80% of nitrogen is wasted and leaked into the environment. Ouch!


Because of this, it is of the utmost importance that farmers and gardeners are mindful of the amounts of fertilizers they are using and what types of fertilizers. Always opt for natural fertilizers, like manure, whenever possible.  


In addition, farmers and gardeners who grow plants on a larger scale should mix nitrogen-fixing crops, such as legumes, into their crop rotation to pull nitrogen from the air and mix it into the soil.  


If you are looking to use fertilizer in your garden, reach out to Knollwood Garden Center. We have the expertise and experience to guide you towards the most effective and environmentally friendly fertilizers that will work for you.