Soil that is too heavy in nitrogen can cause plants to suffer as much as soil with less nitrogen.
With patience, knowledge, and a keen eye, reducing nitrogen in your garden soil is possible.
How to neutralize nitrogen in soil?
First, I limit nitrogen-based fertilizer and use mulch or organic compost instead. Growing nitrogen-fixing plants can also help, as well as soaking the soil with water, hydrating lime, adding organic materials, or not doing and adding anything.
How to Neutralize Nitrogen in Soil: Seven Methods
Adding nitrogen to the soil is easy. However, plants get easily damaged by too excessive nitrogen in the soil.
Removing nitrogen from the soil is more complicated than adding it in (hence tip #7 below).
There are many methods to reduce nitrogen in the soil, but none of them is fast-acting, so I know I must be patient to see any of these methods work.
1. Add nitrogen-loving elements to the soil
These can be inorganic or organic. For example, sometimes, I add fine woodchips or sawdust to the soil.
Carbon in woodchips or sawdust loves nitrogen, and it will help to soak up excess nitrogen.
Alternatively, grow nitrogen-loving plants in the affected area. To remove soil nitrogen, it must bind to another substance.
As a seasoned gardener, I know many things I can grow that will bind to nitrogen.
Every plant can use nitrogen, but some plants, such as tomatoes, squash, broccoli, cabbage, spinach, and others, thrive on it, so I know I can grow these plants even in soil containing lots of nitrogen.
Although the plants I list will grow in nitrogen-saturated areas, they will probably not produce any flowers or fruits.
That doesn’t matter to me since I do not intend to eat the plants, but use them only as sponges for soil nitrogen.
I often soak the soil in water to help push nitrogen away from–or, where not possible, deeper into–the earth. This leaves less of the nitrogen to affect my plants.
3. Do Nothing
This might seem counterintuitive.
But if my plants are already producing lots of leaves, sometimes I consider leaving them alone to continue absorbing the excess nitrogen to repair the soil in readiness for my next crop of plants.
4. Use Mulch
‘Mulching’ refers to spreading mulch on the ground. Mulch is any substance that is laid on the ground to increase the ground’s fertility.
Mulch can either be organic (e.g., straw, wood chips, or fall leaves), or inorganic (e.g., rocks, black plastic, etc.).
Mulch can cause problems for gardeners who use it in excess. This can be a frustrating problem for the inexperienced, but I find I can turn it into a benefit.
To draw out excess nitrogen, I apply mulch to the soil. This works best with inexpensive (hurray!) dyed mulch.
Scrap woods make up the most affordable dyed mulch because this type of mulch absorbs plenty of nitrogen as it breaks down. As mentioned above, I also use sawdust as mulch.
5. Mix Hydrated Lime to the Soil
For sandy soil, add 4 ounces (about 113 grams) per square yard (or about 0.8 meters); for clay soil, add 12 ounces (about 1.4 kilograms).
6. Mix Organic Materials to the Soil
It is possible to decrease soil acidity and deal with excess nitrogen by adding organic materials like crushed marble, oyster shell, bone meal, or hardwood ash.
7. Not Adding Excessive Nitrogen, to Begin with
As said earlier, plants will not produce fruit or flowers if there is excess nitrogen in the soil.
It is possible to reduce the amount of nitrogen in the soil, but it is probably the best strategy of all is to not add too much in the first place.
I am always careful to first test the soil before adding any nitrogen fertilizers, whether chemical or organic.
The Effects of Excess Nitrogen in the Soil
Knowing what to look for, I can visually identify the fallout from high nitrogen levels in the soil by looking closely at plants.
These are some of the typical effects of having too much nitrogen in soil:
Plants redirect much of their energy into producing foliage.
Limited Growth of Flowers
Flowers are the reproductive organs through which plants produce fruits and vegetables.
Excess soil nitrogen results in more green leaves but fewer fruits and vegetables.
When a plant focuses all its energy on creating new leaves, there is little or nothing left for growing roots.
Stunted roots damage the plant’s health since the plant cannot draw sufficient nutrients or water from the soil.
The edges of leaves will look wilted, eventually turning yellow, then brown. Ultimately, the plant will die.
How to be Certain There’s Too Much Nitrogen in the Soil
It is possible to get good visual signs that there’s too much nitrogen in the soil, but when in doubt, I always perform an acidity/alkalinity soil test, which is the only way to be certain.
This is an excellent soil test kit; I find it invaluable for ensuring that soil is healthy. It is inexpensive, efficient, and does the job without fuss or bother.
Frequently Asked Questions about How to Neutralize Nitrogen in Soil
What’s the best time to plant after neutralizing excess nitrogen?
Fall is the best time to replant after neutralizing excess nitrogen if the climate permits the growth of the new plants during winter. If that isn’t an option, plant them early in spring.
How long will it take to repair excess nitrogen in the soil?
When trying to increase the soil’s pH, be patient. It takes time for nitrogen-neutralizing compounds to have a noticeable effect, certainly weeks rather than days.
Plants need nitrogen to produce healthy green leaves and new shoots, but too much nitrogen will harm them.
Always conduct acidity tests to ensure that soil has the appropriate amount of nitrogen. If it doesn’t, apply fertilizer or mulch as needed.
Marcel runs the place around here. He has a deep passion for houseplants & gardening and is constantly on the lookout for yet another special plant to add to his arsenal of houseplants, succulents & cacti.
Marcel is also the founder of Iseli International Commerce, a sole proprietorship company that publishes a variety of websites and online magazines.