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How to Make Nitrogen Fertilizer

By Sarah Metzker Erdemir ; Updated September 21, 2017

Nitrogen is a crucial component of plant growth. It supports photosynthesis and protein formation, making plants greener and stronger, which increases fruit and flower production. Synthetic nitrogen fertilizer is one way to supply your plants with nitrogen, but these often contain harmful chemicals and can actually overfeed your plants and cause them to burn. Making your own nitrogen fertilizer at home insures your plants get the amount of nitrogen they need, and it’s healthier for your soil and your family.

Use compost to fertilize your garden. Compost is not just a growth medium. It’s a natural, slow-release fertilizer. Compost is full of beneficial microorganisms and fungi that break down the soil into nutrients that can be absorbed by the plants. These microorganisms also break down nitrogen in the air and deliver it to plants’ roots.

Plant a cover crop in the fall to fix atmospheric nitrogen into the soil. Legumes like clover, vetch and rye absorb large amounts of nitrogen and can act as a type of green compost. When you till them under in the spring, cover crops decompose and release nitrogen that can be taken up by other plants. Cover crops have the added advantage of protecting your topsoil from washing away in heavy winter rains.

Grow worms to produce nitrogen-rich fertilizer from worm castings. Worms eat soil, and their waste is full of nutrients that feed the soil and can be absorbed by plants. Commercial worm bins are available in garden stores to grow worms indoors, and many garden stores sell worms by the pound that you can put into your garden.

Make a compost tea or worm casting tea to water your plants with or to use as a foliar spray. Fertilizer teas deliver nitrogen to your plants in a form that they can absorb immediately. Plants can also take nitrogen through their leaves, and fertilizer teas protect leaves from harmful mold and bacteria by supporting beneficial microbial growth.

Mix compost and water in a large bucket to make compost tea. Use a 1 to 4 ratio of water to compost. Any compost works, such as well-decomposed kitchen scraps and yard trash or old cow or chicken manure. Let the compost steep in the water for a week, stirring it a few times a day. Strain out the solid matter, and use the tea as soon as possible.

Dilute compost tea with a 1 to 10 ratio of tea to water. There is so much nitrogen in compost tea that it can burn roots and leaves if it’s too strong. Water plants regularly with the compost tea mixture, or spray it directly onto leaves every couple of weeks.

Make worm casting tea by mixing a few handfuls of worm castings and 1 tbsp. of molasses into a large bucket of water. Put an aquarium pump in the water to agitate and oxygenate it. Let it mix for a day, and then apply it to plants as soon as possible. It is not necessary to dilute worm casting tea, and it can be used as a foliar spray or to water plants and give them an immediate boost.


Things You Will Need

  • Compost
  • Clover seeds
  • Vetch seeds
  • Rye seeds
  • Worms
  • Worm bin
  • Compost tea
  • Worm casting tea
  • Large bucket
  • Water
  • Compost
  • Spray bottle
  • Worm castings
  • Molasses
  • Aquarium pump