Fertilization with Ferrous Sulfate Heptahydrate

1. Ferrous sulphate heptahydrate should be prepared with suitable water. Ferrous sulphate heptahydrate can easily become the oxide deposit of ferric trivalent in lime alkaline water, which makes it difficult to be cheated by plants. The best choice is rain, snow or cold boiled water. If alkaline water is used as a last resort, 1 g to 2 G potassium dihydrogen phosphate should be added to every 10 liters of water to make it slightly acidic "improved water". Adding 3% vinegar to alkaline water also has better effect.

2. The amount of application should not be too large and the number of times should not be too frequent. According to many years'experience, adding ferrous sulfate heptahydrate into potted soil is suitable for 5 to 7 grams per pot, and 0.2% to 0.5% for irrigation or spraying. If the dosage is too large and the number of topdressing is too frequent, the plant will be poisoned, the root will become grey and black and rot, and the other nutrient elements will be affected by its antagonism.

3. It is very unscientific to mix a large amount of alum solution at one time for long-term repeated use. Because alum oxidizes slowly in water for a long time to form iron trivalent which is not easy to absorb.

4. Inclusion of ferrous sulphate heptahydrate with decomposed organic fertilizer liquor is more effective, because the decomposition products of organic matter have complexation effect on iron, which can increase the solubility of iron.

5. Ferrous sulphate heptahydrate is mixed in alkaline soil and appropriate potassium fertilizer (but not plant ash) is needed when it is used, because potassium is beneficial to the movement of iron in plants and can increase the usefulness of ferrous sulphate.

6. Ferrous sulfate solution should be used to prevent sunshine in hydroponic flowers and trees. Sunlight mapping iron-containing nutrient solution can make iron accumulate in the solution and reduce its usefulness. Therefore, it is advisable to use black cloth (or black paper) to cover containers or to move into indoor shelters.

7. It is inappropriate to apply ammonia nitrogen fertilizer and elements antagonistic to iron at the same time. Ammonia nitrogen (such as ammonium sulfate, ammonium carbonate, ammonium phosphate and urea, etc.) can destroy organic matter and iron complexes in water and soil, and oxidize iron bivalent to trivalent iron which is not easy to absorb. Calcium, magnesium, manganese, copper and other elements have antagonistic effects on iron, which can reduce the usefulness of iron. Therefore, the amount of these elements should be strictly limited. Fertilizers containing these elements should be applied when the application of ferrous sulfate heptahydrate is best different.