Iron is essential for chlorophyll production. Without it, plants cannot convert sunlight into energy (photosynthesis), leading to general weakness, poor flowering, and yellowing of the leaves.
- Soil Type: It is primarily needed in calcareous and alkaline soils (very common in Malta). In these soils, even if iron is present, it remains chemically “locked,” and the roots are unable to absorb it.
- Type of Iron Needed: The most effective product is Chelated Iron (often labeled as EDDHA). Unlike iron sulphate, chelated iron remains available to the plant even in high-calcium (limestone) conditions.
- Dosage: this varies based on the size of the plant, but generally 5–10 grams is recommended for small plants and 20–50 grams for mature trees, dissolved in 10 liters of water. Always check the label for exact proportions.
- Plant Signals (Chlorosis): The typical sign is the yellowing of young leaves, where the leaf blade turns yellow or whitish while the veins remain dark green. In severe cases, the edges of the leaves dry out and the plant stops growing.
Common Plants List:
- Citrus: Lemon, orange, mandarin.
- Acid-loving (Acidophilic): Gardenia, camellia, hydrangea, azalea.
- Ornamentals: Rose, jasmine, bougainvillea, petunia.
- Fruit-bearing: Grapevine, strawberries, kiwi.
Specific Instructions for Pot Application
Reduced Dosage: For plants in medium-sized pots (approx. 30–40 cm diameter), 1–2 grams of chelated iron dissolved in 2 liters of water is sufficient. Do not exceed this; an overdose in a small container can stress the roots.
Frequency: Unlike open ground, iron in pots is quickly “leached” (washed away) by frequent watering. Instead of one large dose, it is more effective to apply iron every 15–20 days throughout the spring.
Water Quality: Tap water in Malta is very hard (high in lime). If you use it to water your pots, it will neutralize the effect of the iron more quickly.
Pro Tip: Use rainwater or let tap water sit in a watering can for 24 hours before adding the iron; this allows some of the lime to settle at the bottom.
Warning – Staining: Chelated iron (which is dark red) stains floors, marble, and terracotta pots permanently.
Pro Tip: Water with extreme care. If any drops fall on balcony tiles or courtyard pavement, rinse immediately with plenty of water before it dries.
