Today, Ethan Walter discusses nutrient deficiencies: what they are, how to identify them, and how to treat them.

A nutrient deficiency occurs when a plant is not getting enough of a nutrient for the normal plant functions. Common deficiencies are N, P, K, (three of the macronutrients), and Ca, Mg, and Fe.

In previous videos like this one (https://youtu.be/jaZ_x-sgLO4), you learned that nutrients are measured in water with a number called EC. EC is a very useful number, but it doesn’t tell you what *ratio* of one nutrient to another is. If you have the wrong ratio of one nutrient to another, you could be reading the EC as sufficient, when a certain nutrient is actually too low.

Deficiencies are identified by their symptoms. Some common deficiencies are chlorosis, necrosis, and stunted growth. The pattern that those symptoms occur in are important. Pay attention to where symptoms occur, whether it’s on new or old growth, and what combinations symptoms occur in.

Plant nutrients are categorized as either mobile…