How to Add Nitrogen to Your Plants Naturally

Apply several inches of compost to your garden. Maintain a compost pile of grass clippings, leaves and vegetable and fruit food waste, for example, and mix into your garden bed or apply it on top as a mulch. The compost naturally adds nitrogen as well as phosphorus, potassium and other nutrients to your plants. Add new compost every year to keep up a good supply of nitrogen and because it releases the most nitrogen the first year.

Apply a thin layer, up to 1/4 inch thick, of used coffee grounds to your garden. You can mulch directly on top of the coffee grounds, if desired. Coffee grounds are high in nitrogen. They can also be added to the compost pile if you have one.

Use grass clippings as a mulch. Grass clippings are high in nitrogen and while they can be added to the compost pile, if you don't have one, add them directly to the garden. Apply dry clippings only, and only up to 1 inch at a time to prevent foul odors, which are caused by excessive heat if the clippings are piled up too high.

Add several inches of manure to the garden. Manure releases nitrogen into the soil as it breaks down, but the process is slow. Poultry and rabbit manure contain some the highest nitrogen content among the different manure types. Apply manure as you would compost, mixing it into the soil or applying it around your plants like a mulch. Replenish yearly.