Plants need nitrogen to grow: it's a key part of the process they use to derive nutrition from the environment. Unfortunately, most require a source of nitrogen in the soil around them; only a handful (such as legumes like beans and peas) are capable of "fixing" atmospheric nitrogen by binding it so they can use it.  See full article.

  Plants need nitrogen to grow: it's a key part of the process they use to derive nutrition from the environment. Unfortunately, most require a source of nitrogen in the soil around them; only a handful (such as legumes like beans and peas) are capable of "fixing" atmospheric nitrogen by binding it so they can use it.  See full article.