Zinc is a trace element: plants need only tiny amounts of it. Yet without that small quantity, growth stalls and new leaves develop poorly. Zinc acts as a helper in hundreds of plant enzymes, and keeping it in the right range is part of balanced fertilisation.
What zinc does in plants
- Enzyme activity: zinc is a component or activator of a large number of enzymes involved in energy metabolism and protein building.
- Growth hormones: it is needed to produce auxin, the hormone that controls stem elongation and leaf expansion.
- Protein synthesis: zinc helps maintain the structures in cells where proteins are assembled.
- Membrane protection: it helps protect cell membranes against oxidative damage.
- Stress tolerance: well-supplied plants cope better with heat, light stress and pathogens.
Signs of zinc deficiency
Because zinc is not easily moved inside the plant, symptoms appear on new growth first:
- Small, narrow or distorted new leaves
- Very short gaps between leaves, giving a compressed, rosette-like look
- Pale areas between the veins of young leaves
- Slow or stunted growth at the shoot tips
Too much zinc
Like most trace elements, zinc becomes harmful at high concentrations. Excess zinc can interfere with the uptake of iron and other micronutrients, causing yellowing that looks like iron deficiency. It is also toxic to shrimp and other invertebrates. This is why zinc should come as part of a balanced trace element mix rather than as a separate, high dose.
Factors that affect availability
- High pH reduces the availability of zinc and other trace elements.
- Very high phosphate levels can bind zinc.
- Soft, nutrient-poor water and inert substrates provide little zinc on their own.
Supplying zinc safely
The simplest approach is a complete trace element supplement in which zinc is balanced against iron, manganese, copper and the other micronutrients. LGND Heaven is designed for regular, small doses without build-up, and LGND Avalon combines trace elements with macronutrients. Weekly water changes keep concentrations in check.
