SKYHIGH CALMAG

Description

SkyHigh CalMag is a professional calcium and magnesium supplement designed to correct and prevent the deficiencies that are among the most common nutritional problems faced by UK indoor growers. Calcium and magnesium are secondary macronutrients that play fundamental roles in plant physiology — calcium in cell wall integrity and enzyme activation, magnesium as the central atom of the chlorophyll molecule and an activator of ATP synthase. When either element is deficient, plant health deteriorates rapidly and yields suffer.

Why CalMag Supplementation Is Essential in Modern Growing

Most UK tap water is relatively soft, particularly in northern England, Scotland, and Wales. Soft water contains low concentrations of dissolved calcium and magnesium. When you use this soft water to mix nutrient solutions, the baseline calcium and magnesium already present in hard water areas is absent — creating an immediate shortfall that base nutrients alone may not fully compensate for. Coco coir growers face an additional challenge. Fresh coco — even well-buffered coco — has a natural affinity for calcium ions through its cation exchange capacity. In the early stages of growing on coco, the medium will absorb calcium from your nutrient solution before it reaches plant roots, creating deficiency symptoms even when your solution calcium concentration appears correct on paper. SkyHigh CalMag prevents both problems. We recommend CalMag supplementation to every coco and soft-water grower at The Horticulture Company, and the difference in plant health is consistently evident.

Dosage and Application

SkyHigh CalMag is used at 1–2ml per litre of nutrient solution throughout the growing cycle. Add it to water before other nutrients, giving it time to dissolve fully before you introduce pH-sensitive nutrient components. It is compatible with all base nutrient brands and all growing media. For coco growers using new substrate, use CalMag at the higher end of the dosage range for the first two to three weeks to fully saturate the medium’s cation exchange capacity before reducing to maintenance dosing.