Nitrogen is a very important nutrient for plant growth. It encourages lush growth of leaves and stems as well as providing a dark green color to the plant. Nitrogen is particularly important for lawns and other plants that are primarily grown for their foliage. Plants lacking in nitrogen will be spindly and yellowish.
Most chemical sources of nitrogen are made from processed fossil fuels; but there are plenty of natural, organic options available that work just as well. Organic sources of nitrogen are a little trickier, since the amounts – and speed of uptake – vary from one type of material to another. However, organic amendments and fertilizers are often much more forgiving than their chemical counterparts, making it harder (though not impossible!) to over apply and damage plants.
Organic sources of nitrogen for your yard and garden include:
Alfalfa Meal: This product contains not only nitrogen, but phosphorus and potassium. Alfalfa meal encourages beneficial microbes and is an excellent organic source of nitrogen.
Animal Manure: The waste from grass eating animals is an excellent source of nitrogen. Make sure the manure is well composted; since raw manure can not only burn your plants, but the nitrogen is more volatile and can leach away. Also, composting at a high temperature for an extended period of time can generate enough heat to kill weed seeds present in the manure.
Blood Meal: Made from the waste of slaughterhouses, blood meal is a potent source of nitrogen than can burn your plants if over applied, especially on young seedlings. Because it’s water-soluble, blood meal can be mixed with water or applied through your irrigation system.
Compost: Organic compost contains all of the nutrients essential for healthy plants, including nitrogen. Although the exact dosage varies depending on what was composted, overall the product is one of the best ways to enrich and improve your soil.
Cottonseed Meal: This organic source is slightly acidic and provides nitrogen in a fairly slow-release form.
Feather Meal: Chicken feather meal is often dried and formed into pellets which make an easy to use granular fertilizer. Feather meal has a moderate release rate, as soil microbes break down the proteins to make the nitrogen available to plant roots.
Fish Emulsion and Fish Meal: These sources of nitrogen are made from the processed waste of the fish oil industry. Fish fertilizer products are very fast acting, especially if applied in liquid form.
Green Manure: Cover crops – such as alfalfa, clover, peas, and other legumes – are able to absorb nitrogen from the air and release it into the soil. Growing these cover crops in your garden improves the soil just by living in it. Tilling cover crops into the ground at the end of the growing season results in a double dose of nutrients and natural compost. If you rotate crops in your vegetable garden, be sure to add green manures to the rotation cycle.
Soybean Meal: Similar to cottonseed meal, soybean meal is a slow release source of nitrogen made from ground soybeans.