Fertilizers That Can Replace Urea (2024)

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Urea fertilizer for grass and plants is a water-soluble compound that contains carbon, hydrogen and nitrogen. It has long been used in agricultural fertilizers, and occurs naturally as a urinary waste product from protein metabolism in humans and many animals, notes PubChem. For use as a fertilizer, it is manufactured from processed ammonia. The main plant nutrient in urea is nitrogen, which plants need to produce healthy green foliage. You can choose from a variety of alternative synthetic and organic fertilizers that are high in nitrogen content.

Garden plants, crops and lawn grasses cannot acquire elemental nitrogen directly from the environment. Because of this, they have formed mutually beneficial relationships with soil microbes. These microbes in the soil convert atmospheric nitrogen into forms that plant roots can take up and use to produce proteins for growth, metabolism and reproduction. If there is an imbalance anywhere in this system, plants may not be able to acquire the nitrogen they need to remain healthy and productive.

Urea contains 46 percent nitrogen, and this is converted by soil microbes before being made available to plant roots when applied as a fertilizer. However, the nitrogen in urea can easily volatilize, escaping into the atmosphere before plants can use it.

Ammonium nitrate fertilizer is sometimes used in lieu of or combined with urea to compensate for volatile losses because the form of nitrogen it contains is readily available for plant uptake. Ammonium sulfate is an alternate source of nitrogen content that also provides beneficial sulfur compounds to the soil.

Potassium nitrate, a specialty fertilizer, is high in both nitrogen and potassium may also be a good alternative nitrogen fertilizer. These fertilizers act quickly once applied to gardens or lawns, and are readily broken down in the natural environment, notes Ohio State University. Therefore, they require repeated applications during the growing season.

Many organic fertilizers contain high amounts of nitrogen, and, most often, other minerals and nutrients too. Those that contribute nitrogen to soil in significant quantities include most composted manures; field hays; legume hay; and meals of blood, cottonseed, fish and feathers.

These can be used as soil amendments or applied as top dressings for nitrogen supplementation. Rotating crops and planting members of the legume family — including beans, alfalfa, some clovers and peanuts — then tilling these in as "green manures" on a regular basis also helps build soil nitrogen content.

Many commercially sold synthetic and organic fertilizers contain a mix of nitrogen components along with phosphorus and potassium. These are the three main nutrients required by plants, represented on fertilizer labels as the NPK ratio. The nitrogen in these products can come from a variety of natural, organic or chemical sources, including urea. Read labels carefully if you want to avoid using urea.

Although plants require adequate amounts of nitrogen for growth, too much of it can be harmful to plant health. Many sources of nitrogen acidify soils over time. If used in excess, nitrogen fertilizers can lower soil pH below the healthy range for most plants. Also, if too much nitrogen is released into the plants' environment too quickly, they can experience what is often called "plant burn." Always follow label instructions for the application of fertilizers, and test your soil regularly for correct pH and mineral content.