Fertilizer Specialties
Foliar Feeding Micronutrients
Foliar feeding micronutrients is a strategic tool in modern fertilization, especially when quick correction of deficiencies is necessary. In both agriculture and horticulture, micronutrients are often limitedly absorbed via the root due to pH, stress, or soil fixation.
Foliar fertilizers then offer a direct route: nutrients are absorbed through the leaf and can be rapidly utilized for chlorophyll formation, enzyme activity, and stress recovery. Therefore, foliar feeding with micronutrients is an essential component within specialty fertilizer programs.
Why micronutrients are so important
Although micronutrients are needed in small amounts, they are crucial for:
- photosynthesis and chlorophyll activity
- enzymatic reactions and metabolism
- flowering, fruit set, and quality
- stress resistance and antioxidant capacity
Deficiencies quickly lead to growth inhibition and yield loss.
When is foliar feeding necessary?
Foliar feeding is mainly used when root uptake is temporarily limited, such as in cases of:
- high pH and calcareous soils (iron chlorosis)
- cold root zones or oxygen deficiency
- salt stress or high EC in substrate
- acute deficiencies during flowering and fruit set
- stress moments after crop protection
Foliar application bypasses these limitations and delivers micronutrients directly to the leaf.
Which micronutrients are applied via foliar feeding?
The most used micronutrients in foliar fertilizers are:
- Iron (Fe) – chlorophyll formation and photosynthesis
- Manganese (Mn) – photosystem II and enzyme activity
- Zinc (Zn) – growth hormones and protein synthesis
- Boron (B) – flowering and fruit set
- Copper (Cu) – stress enzymes and lignin formation
Foliar feeding is often used as a correction and as a preventive quality strategy.
Role of chelates in foliar nutrition
Micronutrients are preferably applied in chelate form, because chelates:
- keep nutrients stable and soluble
- allow faster uptake through the leaf surface
- prevent fixation or precipitation in tank mix
- provide better transport mobility in the plant
Commonly used forms are Fe-EDTA, Mn-EDTA, and Zn-EDTA.
Foliar feeding and photosynthesis recovery
Micronutrients such as Fe and Mn are directly linked to chlorophyll and photosystems. Deficiencies lead to:
- chlorosis and leaf yellowing
- lower photosynthesis efficiency
- reduced sugar production
- growth stagnation and yield loss
Foliar feeding can therefore quickly stabilize photosynthesis and restore growth.
Synergy with biostimulants: fulvic acid and amino acids
In modern formulations, foliar feeding is increasingly combined with biostimulant components. Fulvic acid supports chelation and increases the mobility of micronutrients, making foliar uptake more efficient.
Free amino acids provide a complete profile of all 20 amino acids, essential for enzyme restoration and stress buffering. Amino acids also support the citric acid cycle (Krebs cycle), making ATP available for active nutrient transport and recovery processes.
Foliar feeding in horticulture and specialty crops
In greenhouse crops, foliar feeding is often applied for:
- prevention of blossom-end rot via calcium support
- greener crops through iron chelate
- quick correction during high production pressure
- stress recovery in heat or EC spikes
Foliar micronutrient feeding is also a standard quality strategy in fruit cultivation and arable farming.
Commercial value for buyers and formulators
For sourcing high-quality foliar feeds, important factors include:
- solubility and stability of chelates
- tank mix compatibility
- quick leaf penetration without phytotoxicity
- synergy with biostimulants and specialty blends
From leaf correction to yield and quality
Effective foliar feeding with micronutrients results in:
- quicker recovery from deficiency symptoms
- higher photosynthesis and vitality
- better flowering and fruit quality
- more stable yields and market value
Overview: foliar micronutrient strategy
| Nutrient | Function | Leaf application |
|---|---|---|
| Iron | Chlorophyll formation | Chlorosis correction |
| Manganese | Photosystem II | Photosynthesis recovery |
| Zinc | Hormones and growth | Uniformity |
| Boron | Fruit set | Flower support |