Fertilizer is a fantastic tool for adding essential nutrients to the soil of your garden, lawn, or potted plants. A quick soil test can let you know which nutrients your soil lacks and steer you towards which type of fertilizer is right for you. However, when it comes to nitrogen, things are even easier.
Fertilizer is great for adding nitrogen to soil. Most all-purpose fertilizers are comprised of nitrogen, phosphorus, and potassium. Both synthetic and organic fertilizers can effectively provide nitrogen to nutrient-deficient soil.
The rest of this article will explain how fertilizer adds nitrogen to your soil, why your soil needs nitrogen, and alternative suggestions for increasing the nitrogen levels in your soil. I will also share some tips for detecting nitrogen levels in your soil before applying fertilizer.
How Does Fertilizer Add Nitrogen to Soil?
Fertilizer is made of three main components; nitrogen (N), phosphorus (P), and potassium (K). Each type of fertilizer is labeled with an N-P-K score, indicating the percentage of each nutrient that is present in the fertilizer.
Some fertilizers have a balanced N-P-K score, with the exact same percentage of each component. Others have varying levels of each nutrient depending on the purpose of the fertilizer.
Before fertilizing your plants, you should always conduct a soil test. A soil test will determine the pH level of your soil and will give you a good idea of what nutrients are either lacking or in excess in your soil.
If you discover that your soil is in need of nitrogen, adding fertilizer is the easiest way to provide that nutrient and increase the productivity of your soil.
After applying fertilizer, the nutrients soak into the soil as water is added, whether it be through a sprinkler system, watering can, or natural rainfall. As the fertilizer sinks in, the roots absorb it and move the nutrients through the plant.
Fertilizers come in two basic formulas:
- Synthetic fertilizers
- Organic fertilizers
Using Synthetic Fertilizers to Add Nitrogen
Synthetic fertilizers use chemical compounds to create high levels of nitrogen. The combination of ammonium and nitrate makes the nitrogen react quickly, providing your soil with the nutrient it needs almost immediately.
This type of fertilizer is relatively common due to its quick reaction time. Because the nitrogen reaches the plant so rapidly, the positive effects of the fertilizer are apparent much more quickly than an organic fertilizer.
That being said, it is essential to note that high nitrogen levels can be unhealthy for animals and people if consumed. If you live on a well-water property, it’s best to keep large amounts of nitrogen out of your soil to avoid the risk of contaminating your water source.
Using Organic Fertilizers to Add Nitrogen
Organic fertilizers are an excellent option for delivering nitrogen to your soil, although they are admittedly much slower-acting than synthetic fertilizers.
Organic fertilizers are made up of animal and plant waste, providing naturally occurring nitrogen without the need for potentially harmful chemical additives. These types of fertilizers can take several weeks or longer to break down enough to effectively reach the roots of your plants. But once it does, it will result in incredibly luscious healthy growth.
Why Does Soil Need Nitrogen?
Nitrogen is one of the key nutrients necessary for healthy plant growth. When nitrogen is lacking in the soil, it can cause low production, weak growth, and even complete failure to thrive.
On the other hand, excess levels of nitrogen can lead to overgrowth and soil toxicity. Because of these reasons, it is vital to maintain a healthy, balanced level of nitrogen in your soil.
Nitrogen is a bit of a shape-shifter, constantly changing form in the soil to support the plants that grow within it. As it moves through the plant, nitrogen gives the ability to create protein and amino acids, and it also assists the plant in creating new cells. Without nitrogen, it is impossible to complete the process of photosynthesis.
As it moves through the nitrogen cycle, the primary forms that nitrogen takes on are:
- Organic nitrogen: Organic nitrogen that lives naturally in the soil is converted to inorganic nitrogen as bacteria digest the organic matter.
- Inorganic nitrogen (NH4+-N): As bacteria grows in the soil, usually due to increases in heat and changes in water levels, inorganic nitrogen increases.
- Ammonium-N: This form of nitrogen is incredibly useful to plants, as it does not move downward, away from the roots, but upward, being soaked up and absorbed by the plant.
If you want a more thorough list of things that can add nitrogen to your soil, you can read my article on the topic: 10 Things That Add Nitrogen to Soil
What Types of Plants Need Nitrogen?
When considering adding nitrogen to your soil, it is essential to evaluate the purpose of the soil. While all plants need nitrogen to grow, different types of plants require different amounts of it.
A helpful way to group plants in terms of nitrogen requirements is by looking at their purpose. Let’s look at how nitrogen requirements vary for lawns, gardens, and potted plants:
- Lawns: Grass needs high nitrogen levels to thrive, much higher than flowers or vegetable gardens. When fertilizing this type of area, a nitrogen-high fertilizer will be most effective.
- Gardens: Flowers, fruits, and vegetables need nitrogen, but not as much as lawns need. A well-balanced fertilizer that contains nitrogen, but not in excess, is the best choice for your garden.
- Potted Plants: Potted plants don’t require as much nitrogen as grass. However, since the soil is in a contained, controlled environment, it may need more nutrient support.
Increasing Nitrogen Levels Without Fertilizer
If you’re not interested in applying a store-bought fertilizer to your property, there are other ways to increase nitrogen levels in your lawn, garden, or other plants.
To support healthy nitrogen levels in your soil, you can:
- Make your own organic compost. Utilize your compost heap and mix some of that organic compost with the soil!
- Sprinkle used coffee grounds on your soil. Save the coffee grounds from your morning coffee and sprinkle them over your garden’s soil. Water will help mix the grounds in and release nitrogen into the soil.
- Water with old fish tank water. Don’t toss the water after cleaning your fish tank! Fish manure contains high levels of nitrogen that can be very beneficial for your soil.
- Create mulch using leaves or grass clippings. Save your grass clippings and raked leaves, and lay them in thin layers at the base of your plants.
- Add wood ash to the soil. After cleaning out the fireplace, you can reuse the wood ash and put a fine layer over the top of the soil. Rainwater will mix it in, providing extra nitrogen where needed.
Making your own fertilizer is one of the easiest ways to add nitrogen to your soil without using harmful chemical additives. It gives you an environmentally-friendly way to reuse your food, yard, and animal waste! You can read more about building your own compost heap in my other article: How to Compost With and Without a Bin (Ultimate Guide)
Organic compost has naturally occurring, healthy levels of nitrogen that, when mixed with the soil, provide excellent support to your plants.
Detecting Nitrogen Levels in Your Soil
Before you apply fertilizer to your soil, it is important to determine nutrient deficiencies and potential overabundance by conducting a soil test. This will help you discover exactly which nutrients your soil needs and the amount necessary to improve soil health.
If you do not have a soil test readily available or choose not to use one, there are some other signs you can look out for that indicate nitrogen deficiencies.
Some of the most obvious signs that your soil is lacking nitrogen are:
- Yellowing or pale green leaves and foliage: When nitrogen is lacking, it directly affects the plants’ ability to create chlorophyll, the chemical responsible for the beautiful green coloring in your leaves. If your plant’s leaves turn from green to yellow, there’s a good chance you have low levels of nitrogen.
- Slow or stunted growth: If your plants are growing extremely slowly or have stopped growing altogether, your plants might be having difficulty creating new cells due to a lack of nitrogen.
- Low productivity in fruit and vegetable gardens: Fruit and vegetable growers need protein to grow healthy levels of produce. Low levels of nitrogen decrease the availability of protein in the soil.
- Lack of new buds or blooming flowers: If your plant stopped blooming or producing new buds, it may be struggling with low protein levels, which can stem from the reduced availability of nitrogen.
Fertilizer is a great way to add nitrogen to nutrient-deficient soil. An at-home soil test can determine the nitrogen levels in your soil, giving you insight into how much nitrogen needs to be added for healthy plant growth.
There are several other ways to add nitrogen to your soil without the use of store-bought fertilizer. You can use organic materials that you probably have sitting around your house.
Nitrogen is essential for healthy plant growth and should be monitored for balanced, robust growth.