Mills Calmag

Mills Nutrients CalMag | Calcium & Magnesium Supplement for Plants

Mills Nutrients CalMag is a premium calcium and magnesium supplement designed to prevent and correct deficiencies in two of the most critical secondary macronutrients in plant nutrition. Whether you're growing in a soft water area, using reverse osmosis (RO) filtered water, or simply pushing your plants hard during peak flower, CalMag is an essential addition to any serious grower's nutrient toolkit.

Who Needs Mills CalMag?

CalMag is particularly important for growers in soft water regions where tap water has a starting EC below 0.3, and for those using RO filtration systems that strip minerals from the water supply. Coco coir growers also benefit significantly, as coco naturally demands higher levels of calcium and magnesium compared to soil or hydroponic growing.

Even in hard water areas, heavily boosting phosphorus and potassium during peak flowering can trigger calcium and magnesium lockout — a common issue that CalMag directly resolves, restoring nutrient availability and bringing plants back to full health quickly.

Note: If you're already using Mills Basis A&B Soft Water, you may not need CalMag — the Basis SW formula already accounts for the lower calcium and magnesium levels found in soft water and RO supplies.

How Mills CalMag Works

Calcium is fundamental to plant structure and function. It reinforces individual cell walls for stronger, more resilient plants, and activates key enzymes that act as biocatalysts — accelerating the chemical reactions that drive healthy growth. Calcium deficiency leads to stunted growth, increased stress, and greater vulnerability to pests, diseases, and environmental fluctuations.

Magnesium is a core building block of chlorophyll — the green pigment responsible for capturing light energy during photosynthesis. Optimised photosynthesis directly translates to faster growth rates, better energy efficiency, and plants that consistently reach their full genetic potential. Without sufficient magnesium, chlorophyll production suffers, leading to yellowing leaves and reduced vigour.

Key Benefits of Mills Nutrients CalMag:

• Boosts calcium and magnesium levels in your nutrient solution quickly and effectively
• Prevents and treats calcium and magnesium deficiencies across all growth stages
• Ideal for soft water growers and those using reverse osmosis filtration
• Essential for coco coir growers where calcium and magnesium demand is naturally higher
• Counters nutrient lockout caused by high phosphorus and potassium use during peak flower
• Strengthens cell walls for tougher, more stress-resistant plants
• Increases photosynthesis rates to support faster, healthier growth
• Compatible with all growing media and nutrient systems