PlantMicronutrient.
An essential mineral nutrient needed only in trace amounts, such as iron, manganese, zinc, copper, boron, molybdenum, chlorine and nickel.
What it means for your plants
Deficiencies indoors usually come from high root-zone pH locking nutrients up rather than from absence in the mix. Choose a feed that lists trace elements, and do not add concentrated micronutrients by guesswork, since boron in particular becomes toxic at low levels.
IN PRACTICE
Yellowing between the veins of new leaves on a plant watered with very hard water is a classic sign of iron being unavailable.
Put it into practice
What 10-10-10 or 3-1-2 really means: percent N, P₂O₅ and K₂O by weight, how to convert to elemental nutrients, and why ratio and dilution matter more than size.
NPK numbers explained: what a fertilizer label really tells you
