FREE sources of nitrogen fertilizer for garden soil

Finding natural sources of nitrogen for your garden is an easy thing to do. After years of failed gardening attempts, I sent a soil test to my closest testing lab. It turned out that I was in need of nitrogen! Since I wanted to keep my gardens organic, I found 10 ways to add a natural source of nitrogen for plants using organic material only.

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How to add natural sources of nitrogen to your backyard garden in 10 easy ways every growing season.

The best decision I ever made was sending a soil test to the UF Extension Soil Testing Lab. Receiving a complete soil test to find the levels of NPK (nitrogen, phosphorus and potassium) in your growing soil is crucial for the longevity of the soil and to grow healthy crops.

I had such a hard time growing edible crops. Once I learned that my gardens needed a nitrogen boost, my plant growth took off!

Whether you’re a beginning gardener or a seasoned gardener, your soil needs fertilizing. And if you’re planning to garden for the long haul then it’s best to utilize organic nutrients.

Nitrogen fixation and why nitrogen is important

“The act of breaking apart the two atoms in a nitrogen molecule is called “nitrogen fixation”. Plants get the nitrogen that they need from the soil, where it has already been fixed by bacteria and archaea.”

– Dr. Christopher S. Baird

Nitrogen deficiency in plants decreases photosynthesis, affecting the plant’s productivity. Plants also need nitrogen to produce chlorophyll, the basis of photosynthesis. 

I am still learning to understand this whole process and instead of acting like I know everything, please visit this great link to read more about this process. Here’s an excerpt from the article:

“There are many ways that nature gets nitrogen into the soil.  Lightning strikes, rainfall, cut greens, fresh poop, fallen ripe fruit, all help.  Most of all, there are soil bacteria which can transform atmospheric nitrogen into fixed nitrogen: inorganic compounds that are usable by plants.”

– Diane Cynthis Beeler of Finch Frolic Garden Permaculture

What I can say, with confidence, is I do know that we don’t need chemical fertilizers for the health of your plants. The air and soil have a symbiotic relationship that existed long before humans planted a garden, and nitrogen plays a vital role in that relationship. And if we don’t nurture that relationship, it will only take more work and more money to grow organic crops. 

Golf courses, for example, are an unfortunate use of space. They will likely never be able to be reused for organic growers due to the high levels of commercial fertilizer and weed killer utilized to produce such beautiful green grass. So much chemical has been dumped on the ground and soaked up by the soil that the microorganisms that work so hard to provide healthy soil have likely all been reduced to nothing.

Nitrogen deficiency in plants

Before we move on, it’s important to note that some soil might have too much nitrogen. So just because mine was deficient in the amount of nitrogen, it doesn’t mean yours is. 

Consider purchasing a soil test kit to figure out exactly what your NPK ratio is, and what your garden beds need, for the best results. Also, learn the signs of a nitrogen deficiency in garden plants. You don’t have to see the plant roots to know if you have healthy plants.

Healthy, green plants are what you often want in your garden. The top signs of a nitrogen deficiency are:

• Slow growth (small leaves when they should be larger)
• Excessive leaf drop
• Yellow leaves 
• And, in my case, low yields

Alternatively, you can have too much nitrogen, as well. For example, if you have a healthy balance of nitrogen and still add nitrogen to your gardens. The signs of an over-abundance of nitrogen (over-fertilization) are:

• Actively/rapidly growing plants producing little-to-no fruit/vegetable production or flower formation
• “Burnt” leaves (brown, gray or yellow)
• Cupped leaves, or even abnormally thick leaves
• Wilted plants that might even die from nitrogen shock

Enough of sad stuff, though. Let’s finally move on to how you can incorporate organic nitrogen sources to feed your vegetable plants this season.

Bone meal and blood meal

Bone meal and blood meal are great, natural ways to meet your nitrogen needs and also add phosphorus source to your garden beds. You can buy bags of organic bone and blood meal at most garden centers.

You can also make your own bone and blood meals. I plan to use this recipe by Salt in My Coffee called “How to Make Bone Meal”. 

Recently I read about feather meal, which is made from poultry feathers by grinding and drying them. The internet claims that feather meal is slow release, as opposed to blood meal which is a fast-release source of organic nitrogen fertilizer. Both are thought to have high nitrogen levels and a good option for organic soils. The jury is out on whether feather meal provides nitrogen in a usable form, though.

Always do your research before incorporating practices on your homestead, folks.

Planting beans

Did you know different crops give and take certain things to and from the soil it’s planted in? Utilizing a crop rotation of nitrogen-fixing plants is one of the best ways to add essential nutrients and yield a healthy soil.

By planting beans, the crop will act as a host plant and add small amounts of their own nitrogen to the crops around them. This makes beans a great planting companion for strong nitrogen feeders such as broccoli or cabbage. And you can utilize the plant material in your compost pile at the end of the season.

Once I started learning and reading about gardening I just thought that was the coolest thing! That’s why companion gardening is so important and can boost your gardening game BIG TIME. 

I’ve enjoyed companion gardening in each previous year I’ve practiced, and feel like it’s a best choice and best practice for every home garden.

Want to keep track of your harvest with my free homesteading PDFs and join the flock?

Cover crops

Incorporating into your routine garden planting planning can be one of the most beneficial ways to add a good source of nitrogen, naturally. 

Planting cover crops is an age old gardening practice. As early as the 1900s, vineyards used cover crops to add nitrogen, improve water penetration by promoting healthy soil aeration and reduce erosion. These are all reasons to utilize them in our home gardens, too!

If you fight sandy soils, cover crops are a great way to create nutrient-rich soil by tilling the crop back into the soil after the season was over. 

Or if you’re a no-till type of gardener, let the cover crop grow and complete its season and compost in place. This increases the presence of organic matter and improves soil fertility. Hot tip: it’s even healthy to do this with grass clippings! Not all crop residues are bad to leave.

Cover crops can also help fight weeds, and are still often used in orchards to act as a weed barrier and prevent erosion around fruit trees, thus promoting hydration for the crop.

If you have livestock, consider growing cover crops such as cow beans, wheat, field peas or clover. Radishes can even be planted as a cover crop! If you have the square feet to spare, plant these crops early enough in the season so your livestock (cows, goats, etc.) can graze on fresh, leafy vegetables and grains before the soil temperatures drop. 

I think the versatility of a cover crop is vastly under-appreciated. 

Coffee grounds

If your house is like my house then you also have an abundance of coffee grounds! Coffee grounds can be a great addition to your nitrogen cycle.

Coffee grounds don’t immediately add nitrogen to your soil, though. Instead, they slowly break down adding organic matter and nitrogen to your soil slowly.

Although adding organic matter to your soil can help with drainage, aeration, and water retention sometimes composting coffee grounds can be a better use of the source.

You can mix coffee grounds directly into the soil when planting or compost them – gardener’s choice.

Leaves for mulch

Leaves also act as a good source of nitrogen for plants, provide aeration and can be used for mulch! Mulching is great because it helps with surface water retention, keeping your soil cool, prolonging the life of your soil and so much more.

It’s easy to deal with mulch when you’ve used leaves because at the end of the season, you can just mix the leaves into the soil! Presto! A good nitrogen source AND organic matter, all at once.

I once tried mulching with this stuff called “EZ Mulch”. I will NEVER do it again because I’m pretty sure there’s some type of chemical on that stuff. It was slimy when wet, got very matted and didn’t let plants grow through and just caused issues. 

10/10 do not recommend. 

Compost tea

If you’re already composting, then this one is easy. Soak a bucket full of compost in water and strain the liquid (the tea) to utilize as a liquid fertilizer. No special water supplies required!

Compost teas are most often a concentrated liquid, so you will likely want to dilute it before adding it to your gardens.

Aged chicken manure

I know I already mentioned Salt in my Coffee but I’m going to do it again. Anna wrote a great article about the Deep Litter Composting Method called “Chicken Manure Compost in 18 days”.

Chicken manure is a type of manure that contains high levels of nitrogen. It can be one of the best and most natural sources you can find. You do have to let it age because it can “burn” your plants if you don’t. That’s when Anna’s method comes in handy.

Out of all the animal manure I have dealt with so far, poultry manure has been the highest in nitrogen. It was a good thing I read about it prior to utilizing it. I had big plans to add the manure to my gardens and it would’ve fried them completely.

Fish emulsion

You can buy liquid fish emulsion or fish meal at your local Tractor Supply or garden stores. Due to its superior levels of nitrogen, you’ll want to dilute it so you avoid burning your crops. The Spruce has a great guide on making your own organic fish emulsion fertilizer and what to look for.

I use SUPERthrive in my gardens as a plant nutrient and find it starts working in a very short time. SUPERthrive is a very strong fish emulsion fertilizer, packed with amino acids, sure to boost your edibles. I’ve used this liquid fertilizer on my cut and come again vegetable gardens. It would be a great addition to any victory garden.

Rabbit manure

Getting access to rabbit manure might be a little tricky if you don’t have rabbits. If you know someone who does have rabbits, though, it could be easy and free!

Unlike chicken manure, rabbit manure can be added right to the gardens since it isn’t hot. If you add the manure directly to your gardens, it will act as a slow release organic fertilizer. Additionally, it’ll assist in supporting the roots of the plant all season by adding just enough nitrogen.

Adding nitrogen to your backyard gardens in 10 natural ways

There are loads of other ways to add nitrogen-rich fertilizers to your gardens in a natural form. The good news is that these natural sources of nitrogen are easily accessible. And they won’t waste loads of fossil fuels getting to your backyard.

And if for some reason you don’t have access to these specific options, don’t worry. There are other more out-of-the-box options like human urine (not kidding). Urine is a high-nitrogen fertilizer, but the best way to use it is heavily diluted. Talk about organic fertilizers!

If you are still purchase fertilizer from the store, it’s always a good idea to find an organic fertilizer. And remember, the first number always represents the nitrogen ratio (NPK). 

No matter what method of gardening you’re using, these nitrogen sources can be used to boost plant growth all season. Let me know if you have any questions, comments, concerns, tips, tricks or what have you. I’d love to hear it!

More on gardening:

• New to vegetable gardening?
• Best vegetables for raised garden beds
• How to plant a vegetable garden