How to Increase Nitrogen in your Garden Soil: Natural Methods
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Can you increase nitrogen levels in your garden naturally? Yes! If you are looking to create a thriving vegetable garden, you need to make sure that your soil has enough nitrogen. Nitrogen is an essential nutrient for plant growth and development. Without it, many plants will not thrive. Increasing nitrogen levels in your garden can be especially helpful for certain types of plants, though you must proceed with caution in some areas of your garden. In this article, we explain the benefits of nitrogen for plants and provide some tips on how to tell if you have enough nitrogen in your soil. Then, we provide suggestions on how to introduce more nitrogen into your garden if necessary, using natural methods.
What is Nitrogen?
Nitrogen is a key nutrient for plant growth. It is found in the atmosphere and is essential for the formation of chlorophyll, the molecule that helps plants convert sunlight into energy. Nitrogen is also involved in the development of other important plant molecules, including proteins and DNA.
Nitrogen is also a major component of the soil. It is found in organic matter, such as dead leaves and twigs, and it is released into the soil when these materials decompose. Nitrogen is also present in some minerals, such as limestone.
Why do Vegetable Plants Need Nitrogen?
Nitrogen plays a vital role in plant growth and development. As we mentioned, it is necessary for the production of chlorophyll, which allows plants to convert sunlight into energy. In addition, nitrogen aids in the creation of proteins in the plant. These are essential for cell growth and development. Finally, nitrogen is necessary for the production of enzymes. Enzymes are responsible for many biochemical reactions that take place in the plant, including the breakdown of nutrients and the synthesis of new compounds.
Nitrogen levels in your soil can easily be depleted by run-off or by heavy growing.
How Much Nitrogen Does a Vegetable Garden Need?
The amount of nitrogen that your garden needs will vary depending on the type of plants you are growing. In general, plants that are harvested above the soil for their greens (not their fruits or roots) thrive with healthy amounts of nitrogen – think leafy greens like kale, chard, spinach, and lettuce. The areas of your garden in which you will grow these types of vegetables should be especially nitrogen-rich.
In contrast, vegetables that are harvested for roots or fruits (carrots, potatoes, tomatoes, eggplant, etc.) may struggle if nitrogen levels are too high. However, most gardens will thrive with around 40 parts per million (ppm) of nitrogen.
Soil Testing for Nitrogen
The best way to tell if your soil has enough nitrogen is to test it. You can purchase a soil test kit from your local nursery or gardening store, online, or from a University Extension Office. These kits will usually come with instructions on how to take a sample of your soil and send it to a lab for testing. The results of the test will tell you the levels of nitrogen and other nutrients in your soil.
(For more information on soil testing options, see our article on the topic here).
If your soil test shows that there is not enough nitrogen in your garden, don’t worry! There are several ways to introduce more nitrogen into the soil.
Increasing Nitrogen in your Soil Naturally
While it is possible to increase nitrogen levels in your soil using commercial applications of fertilizer, we prefer to address nitrogen deficiency naturally.
There are a few ways to increase the nitrogen in your garden naturally.
Add organic matter, such as compost or composted manure, to your soil
Compost, or composted manure, will release nitrogen into the soil as the materials it contains decompose. A high-quality organic compost from a garden center is a good choice, or you can make your own compost throughout the year at home with food and yard scraps.
Compost should be added by spreading a layer on top of the soil and then tilling it in, or by working it into the top few inches of the soil with a shovel or rake. It can also be added to the hole you dig when you plant vegetables or incorporated into a sheet mulch garden bed when you create it.
Grow Nitrogen-Rich Cover Crops
You can also grow cover crops, such as alfalfa or clover, in your garden to increase nitrogen levels naturally. Cover crops are plants that are grown specifically to improve the quality of the soil. They are often used in agricultural fields, but they can also be used in home gardens. After a cover crop has been allowed to grow for a few months, it is then chopped and turned into the soil, where it will decompose and release nitrogen. This is a great choice between seasons.
Grow Nitrogen-Fixing Crops
Another way to increase nitrogen in your garden is to plant nitrogen-fixing plants that have a symbiotic relationship with bacteria in the soil. The bacteria live on the roots of the plants and convert nitrogen gas into a form of nitrogen that can be used by plants. Some examples of nitrogen-fixing plants include legumes, such as peas, beans. You can use plant rotation in your garden and put these plants in where nitrogen-depleting plants had been placed previously (this is why crop rotation is so important!).
Spread Grass Clippings
Grass clippings from your lawn are an excellent source of nitrogen as long as they have not been treated with any chemicals. As an added bonus, grass clippings can serve as mulch early in the season when spread over the surface of the garden between plants. The nitrogen will leech as the grass decomposes.
Use Natural Fertilizers or Garden Amendments
While the above methods are perhaps the most “organic” means for increasing nitrogen in your garden, you can also add specific components to your soil to increase nitrogen. We prefer to avoid commercial fertilizers that often contain more than we need, but other more simple options include:
- Mixing Coffee Grounds into your soil (they decompose gradually and also create some space for aeration in the garden)
- Adding fish emulsion (a nitrogen-rich natural fertilizer that also contains other beneficial nutrients)
When should you NOT add Nitrogen to the Soil?
It is possible to add too much nitrogen to your soil. This can happen if you use too much fertilizer or allow animal manure to sit in one spot for too long without incorporating it into the soil. Nitrogen can also accummulate in the soil if you do not rotate your crops annually.
Too much nitrogen in the soil can cause problems such as:
-vegetables with large leaves but little fruit or root development (do not use nitrogen-heavy fertilizer with your tomatoes, for example, especially later in the season when you want plants to focus on fruit growth)
-runoff into waterways
If you suspect your soil is high in nitrogen, stop adding amendments that contain nitrogen and plant vegetables that will absorb it instead (like leafy greens ). This will help bring levels back down over time, and is safer than trying to add chemicals to balance out the nitrogen. You can also have your soil tested again to see if the levels have changed.
With a little effort, you can easily increase the nitrogen levels in your garden soil and create a lush, healthy environment for your plants to thrive! By using natural methods, you can avoid the potential risks associated with commercial fertilizers.