11 Natural Nitrogen Sources All Gardeners Need to Know

Nitrogen is a vital part of our soil’s health, and if you suspect a deficiency, try adding some of these natural nitrogen sources.

Understanding the complexity of your garden soil is something that takes time for gardeners; I finally began to study all the nutrients that plants need. Two years ago, many of my plants began to experience stunted growth and yellowing leaves. I spent days researching what was wrong with my plants – they need some natural nitrogen sources.

One of the most common gardening mistakes that newbies make is not amending their soil each year. You assume that since you added fertilizer two years ago everything is fine.


Plants deplete the soil every year, and all plants give and take nutrients differently. Nitrogen is one of the most essential nutrients, and without this important one, your plants won’t grow.

If you’re like me, using chemical anything in your garden is a big no-no. I prefer to use cheap fertilizers that I have around the house or natural ones from the store. If you suspect that your plants need nitrogen, here are a few natural nitrogen sources that you can use to fix the problem.


Why is Nitrogen Important in Garden Soil?

Every plant requires three main nutrients – nitrogen, phosphorus, and potassium. It’s typically abbreviated NPK, and without these, your plants won’t be able to grow. Each nutrient plays a unique role in the growth and development of the plant.

So, why do plants need nitrogen?

Nitrogen is needed for plants to grow and make themselves. If your plants don’t have access to nitrogen, they’ll be unable to make proteins, amino acids, and DNA, which is why a nitrogen deficiency causes stunted growth. Your plant is unable to make their plant cells.

If your plants or soil have a nitrogen deficiency, it’s fixable, and there are two general routes that gardeners use to fix the issue. You can either use organic or non-organic nitrogen sources, added to the soil.

I prefer to use natural nitrogen sources rather than non-organic, chemical fertilizers.

Signs of a Nitrogen Deficiency

You can see how these leaves are gradually turning yellow, one of the many symptoms of a nitrogen deficiency.

Plants need nitrogen, so they’ll be quick to tell you if they have a deficiency. Most signs appear early in the growing season, and if caught early, you’ll be able to fix the problem. Your plants will survive.

Some signs of a nitrogen deficiency include:

  • Stunted growth
  • Small leaves
  • The lowers leaves turn yellow first and might fall off the plant.
  • Yellowing gradually creeps up the plants, causing more leaves to turn yellow and fall off the plant.
  • The flowers are smaller than average and might die faster.
  • If the plant produces fruits, they’ll be small and low quality.

How Do You Know if Your Plants Need Nitrogen

While all of these signs point to a nitrogen deficiency, they aren’t unique to this problem. Yellowing leaves are a sign of many different issues, so gardeners have to use their investigative skills to figure out what is the real problem.

Testing your soil is the best way to know if your soil lacks nitrogen, and I highly suggest that you test before adding more nitrogen purposefully. Too much or too little nitrogen is damaging; you can burn plants if you add too much.

So, how can you test your soil to figure out if you need more nitrogen?

  1. Use a professional test that sends soil samples to a lab. Your county extension office should offer this for around $20, and considering they are highly accurate, it’s a great garden investment.
  2. Use a test kit at home. These tests aren’t as accurate, but if you want to test rapidly throughout the gardening season, it is most practical. I like these Rapitest Test Kits by Luster Leaf; there are 40 tests in one kit!

11 Natural Nitrogen Sources

1. Alfalfa Meal

If you check out your local garden store, they should sell bags of alfalfa meal for you to buy. Alfalfa meal is rich in nitrogen (not as much as blood meal listed below), and it’s a great choice for gardeners.

Make sure you follow the instructions on the package when applying it to your garden. Typically, you add it to the soil surface and water deeply to encourage it reaching your plants’ roots.

2. Bone & Blood Meal

If you visit any local garden store, you’ll be able to find bone meal and blood meal. These fertilizers are great ways to add nitrogen and phosphorus to your garden plants.

Not only can you buy bone and blood meal, but you also can make your own. You can save bones up and make bone broth or meal to feed to your plants. Both are high in nitrogen and need to be applied appropriately to your plants.

Using blood meal is one of the quickest ways to add nitrogen to your garden soil. It’s rich in nitrogen, and when you add it to the soil surface around your plants and water deeply, your plants receive a great boost fast.

Are there downsides to using blood or bone meal? YES!

The biggest problem is that blood and bone meal smell. It attracts animals to your garden, even large ones like bears, if they’re in your region, so if that’s a worry for you, alfalfa meal is a good alternative.

3. Coffee Grounds

Coffee grounds may be used in the garden fresh or composted, and it contains around 5% nitrogen by weight. Now, if you’re only making a cup here or there, you might not feel like you have enough coffee grounds to make a difference in the nitrogen levels in your soil.

Here’s an idea.

Ask local coffee shops to save coffee grounds for a day or two. Many will do so if you tell them you’re a local gardener looking to amend your soil. I always love this gardening on a budget tip!

4. Cover Crops

Sometimes called green manure, planting cover crops in your garden is a great way to add more nitrogen to your soil. Typically, you plant cover crops as part of your crop rotation, but you also might plant cover crops at the end of the growing season. Options include alfalfa, clover, peas, and other legumes.

Growing cover crops improves your soil simply by growing in the soil. Then, till the cover crops into the ground at the end of the growing season, so it decomposes in the soil, adding more nutrients.

5. Fish Emulsion

Fish emulsion is another natural nitrogen source. Stores sell liquid fish emulsion, but you have to dilute it because the nitrogen level is so high that it’ll burn your plants. You also can try to make your own fish emulsion as well.

Not only does fish emulsion contain nitrogen, but it also has tons of other vitamins and trace minerals that your plants need to thrive. If you look at a bottle of fish emulsion, most have an NPK ratio of 5:1:1, and it also lists other micronutrients that your plants need like:

  • Calcium
  • Sodium
  • Chlorine
  • Sulfur
  • Magnesium

6. Grass Clippings

Do you have grass that you cut weekly? If so, you have a free, natural nitrogen source! When composted, grass contains 3% nitrogen by weight, and it’s so easy to use even if you don’t compost it.

Grass clippings work as a mulch as well, gradually decomposing into the soil. This is a much slower way to add nitrogen to your soil, but if you’re working to make your soil better, in general, this is a free method.

7. Human Urine

No lie, this is pretty gross, but human urine is one of the best natural nitrogen sources. It also contains trace minerals that help your plants grow. In general, urine contains 5% nitrogen by weight, but it has to be diluted before applying it to your plants. Dilute the urine using the ratio of 5 parts water to 1 part urine.

8. Leaves

If you have trees in your backyard, you have another one of the best natural nitrogen sources – leaves! Leaves are versatile in the garden; you might be surprised by what you can do with fall leaves. They work for adding nitrogen to your plants, improving aeration, and acting as an organic mulch.

You can mix fall leaves into your soil at the end of the gardening season, and by the time spring arrives, they decomposed and added nitrogen to your soil – score!

9. Manure

Manure from rabbits, cows, horses, goats, sheep, and chickens is one of my favorite natural nitrogen sources – probably because I have chickens! It tends to be very high in nitrogen, ranging from 4-9% nitrogen by weight.

It’s essential to mention that manure must be aged and composted before using in your garden except for rabbit manure. These materials are so high in nitrogen that they’ll burn your plants if you forget to compost and age them.

Chicken manure is actually the highest in nitrogen out of all the animal manures, so make sure you compost that.

10. Manure Tea

If you have animal manure, you can make manure tea, which is a fast way to give your plants a nitrogen boost. You cannot use cat or dog manure, but all you have to do is add manure into a bucket and fill it with water. Let it soak, and then the water becomes the manure tea.

Use manure tea to water your garden and give them a boost. You can dilute it further if you want to give smaller boosts, perhaps to all of your garden plants.

11. Planting Beans

If you’re looking for a natural way to add nitrogen to the soil slowly, consider planting beans. Everyone knows that plants absorb nutrients in the soil, but many have no idea that plants also give certain nutrients to the soil. When you’re planting beans, you’re adding nitrogen to the soil without any work or fertilizers.

That’s why beans are a great companion plant for broccoli, cabbage, or any plants that require a lot of nitrogen. So, try growing green beans everywhere and see what happens!

Fix Your Nitrogen Problems

Finding natural sources of nitrogen isn’t as hard as you might think. Mother Nature provides us with everything that we could need if you know where you look and how to use it to fix a nutrient deficiency in your garden.

Similar Posts


  1. The nitrogen legumes generate is mostly for themselves. Unless you leave the beans which is where the nutrients are concentrated on the vine and compost the entire plant, you are not adding anything to your soil. Sorry to burst this common myth. Check it out for yourself at gardenmyths.com . It’s very humbling and enlightening.

Leave a Reply

Your email address will not be published. Required fields are marked *