How to Add Nitrogen to Soil in Any Season

how to add nitrogen to soil

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Project Overview
  • Working Time: 1 - 3 hrs
  • Total Time: 1 - 3 hrs
  • Skill Level: Beginner
  • Estimated Cost: $0-20

At times the location we choose for our plants is less than ideal, and we need to amend the soil by adding in some extra nitrogen or fixing the location in other ways. This can be done quickly and easily, or it can be done in a process that takes months but fixes the nitrogen quite dependably.

Why Does Soil Need Nitrogen?

Soil needs nitrogen because it is invaluable to plants; it's what makes them grow. It's the N of the famous big three: NPK, Nitrogen, Potassium, and Phosphorus. Nitrogen allows plants to produce the protein and amino acids they need to thrive. Without this, a plant's growth can be slow or die outright.

Here are several ways to quickly and easily add nitrogen to soil and check that our pH is in the right place, so that you don’t cause any new issues when you solve one.

Why Perform a Soil Test First

Before you add nitrogen to your soil, you need to determine how nitrogen will affect the pH of your soil. This can be done through a soil test (see step one).

Each plant has the perfect pH zone that it prefers when it comes to soil, and your local soil may not fit the bill for the plant you are trying to grow. Sometimes the pH of the soil is perfect, but the soil is just not rich enough. The natural inclination is to add organics, but in doing so, you will lower the pH. To make sure that you do not kill your plants this way, it's a good idea to ensure that your pH is not already low; if it is, then along with your nitrogen, you can add an amendment to raise the alkalinity of your soil to compensate for a drop in pH when the nitrogen is added.

What You'll Need

Equipment / Tools

  • Trowel
  • Small rake
  • Gloves


Fall Amendments

  • Old coffee grounds
  • Compost/manure
  • Leaf mulch
  • Straw

Spring Amendments

  • Blood meal
  • Feather meal

In Season Amendments

  • Fish emulsion


Adding nitrogen to your soil is relatively easy; the only thing that changes is what you should add and when you should add it.

Certain materials will not be bioavailable for use by the plants until they are broken down into the soil. So if you need a boost of nitrogen immediately for your peppers, it will not do you any good to put straw down on your soil, as the plants will not get any nitrogen tied up in the straw until it breaks down. Instead, you would want to choose a product that makes nitrogen available immediately.

White Is Bioavailable?

Bioavailable is a descriptor of the availability of a substance to be absorbed and readily used by an organism.

How to Add Nitrogen to Soil

  1. Test the pH of Your Soil

    To test your soil, grab a soil pH test kit, make one yourself, or contact a nearby Extension Office to coordinate a test. You shouldn’t add nitrogen to your soil without determining what the current levels are.

  2. Determine the Amendment to Add

    With the results of the pH test kit, you can figure out what amendment to add. The best soil amendment to use for nitrogen depends on when you want to add the amendment and how fast you need nitrogen to reach the plant. The amendment you use also affects when you should apply it.

  3. For Amending in Growing Season

    For plants that need an immediate nitrogen boost, you will want to use an immediately bioavailable material. A great product for this purpose is a fish emulsion which can be store-bought or homemade.

    Applying the fish emulsion is done either as a soil drench or as a spray. Unfortunately, the product does have a smell, as you can imagine. You will need to reapply often, but it will get the job done.

  4. For Amending in Spring

    When starting the season or just providing some ongoing feeding, it is best to choose a dry product that can be mixed into the soil that will release and absorb slowly. Blood and feather meal are ideal candidates for this job, which provide long-lasting slow releasing readily bioavailable nitrogen.

    Adding these to the soil is easy:

    • Use your trowel to scoop some from a container and use the rake to gently mix the meal with soil until the two are well blended
    • Water the area until the soil is damp.
    • Reapply the meal every two to three months through the season, remembering to check your soil's pH.
  5. For Amending in Fall

    When your garden has gone fallow, and you are preparing for the following spring, it is time to add amendments that are not immediately bioavailable and will benefit from the fall, winter, and early spring months to break down and diffuse, and be absorbed into the soil.

    Examples of these amendments would be coffee, tea, compost, manure, straw, leaf, and grass clippings.

    Adding these to your garden can be as easy as broadcasting the material over your garden beds and letting nature take its course or spreading the material evenly into the soil and raking it as needed.


    Besides adding organics, you can also increase nitrogen levels in your soil with commercial fertilizers, cover crops, and nitrogen-fixing plants.

  • What is the fastest way to add nitrogen to soil?

    The fastest way to add nitrogen to soil is by using a fertilizer with a high nitrogen content in the NPK formulation. There are a few fertilizers formulated for feeding lawns on the market that have ratings of 9-0-0.

  • Does Epsom salt increase nitrogen in soil?

    Epsom salt does not increase nitrogen in soil. Epsom salt has a nutrient value of 0-0-0, which means it provides zero macro-nutritional value to your plants.

  • Does coffee provide nitrogen to soil?

    Coffee can provide nitrogen to soil, but not in the right away. It takes a good bit of time for coffee's nitrogen to become bioavailable in the soil for plants to use. The coffee first needs to be broken done by the soil, then its nutrients will be made usable in the soil by the plants after many months.

Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Understanding Nitrogen in Soils. UMN Extension.