Calcium,
Phosphorus,
Nitrogen,
Potassium,
Sulphur,
Magnesium and
Iron are the primary nutrients that plants need. If you come up against a deficiency in one of the elements in your plant(s), you are in some serious trouble. Brown spots, yellow spots, burned leaves and leaves falling off are just some examples. And if you don’t come up with a solution quickly, your beloved plant(s) may pass the point of no return.
The CANNA Deficiency Guide is a great help. It gives you a bit of background information about each nutrient, explains the symptoms, development and reasons for a deficiency, and provides you with a solution at the end.