Using Epsom Salt in Fertigation and Foliar Feeding

Fertigation and foliar feeding demand more from a fertilizer than soil application does. The product must dissolve completely, leave nothing behind in pipes and nozzles, and mix safely with the rest of the nutrient programme.

Why heptahydrate is the standard

Magnesium sulphate heptahydrate dissolves quickly in cold water and is highly soluble, which makes it easy to prepare concentrated stock solutions. That is why most greenhouse, hydroponic and drip-irrigation programmes use it as their magnesium source.

Specifications that matter

• Water-insoluble matter — keep it low. Insolubles settle in tanks and block emitters.
• Purity — a high assay means fewer unknowns in the nutrient solution.
• Heavy metals — important for food crops and for hydroponic systems that recirculate solution.
• Free-flowing crystals — caked material is slow to dissolve and hard to dose.

Mixing with other fertilizers

Magnesium sulphate is compatible with most common fertigation products. The usual caution applies to calcium: mixing concentrated calcium nitrate and sulphates in the same stock tank can form insoluble calcium sulphate. Growers typically keep calcium in a separate stock tank, often called the A tank, and sulphates and phosphates in the B tank.

Foliar sprays

Foliar magnesium is used to correct visible deficiency quickly. Spray in cooler parts of the day, follow local recommendations on concentration, and test on a small area first to check crop tolerance.

Packing for greenhouse buyers

Fertigation customers often prefer 25 kg bags with an inner liner to keep the product dry and free-flowing. We can supply heptahydrate in the crystal size your customers' dosing equipment is set up for.