Nitrogen is one of three critical elements in fertiliser. But why do plants need nitrogen?
Plants use nitrogen to make their leaves, stems and branches. So generally, the more leafy a plant is, the more nitrogen it needs. Plants that are lacking nitrogen have pale leaves, a lot paler than a plant of the same species that is doing well. They can also have saggy stems.
More than 3/4 of the earth’s atmosphere is nitrogen, so why don’t all plants get enough nitrogen? Because, unfortunately, most plants cannot access nitrogen from the air. In the wild, plants get their nitrogen through their roots. Nitrogen is in the soil from the decomposition of organic material like animal droppings and fallen branches. Worms and fungus and other living creatures in the soil eat the organic material and excrete it as inorganic nutrients. That’s why seeing worms in your soil is a great thing.
Plants in pots and plants in soil that doesn’t have access to the earth needs you to add nitrogen to them in the form of fertiliser.