High-strength CAL-MAG for fast-growing, heavy-feeding plants. ✅ Chelated Calcium & Magnesium for rapid absorption ✅ Helps prevent blossom en
Every healthy plant needs calcium and magnesium — two of the most important yet often overlooked nutrients in gardening. That’s where Cal-Mag comes in. A Cal-Mag supplement provides a precise balance of calcium (Ca) and magnesium (Mg) to strengthen cell walls, improve nutrient uptake, and enhance chlorophyll production.
If your plants show signs of yellowing leaves, weak stems, or poor fruit quality, they may be suffering from a Cal-Mag deficiency. Adding the right supplement quickly restores strength and resilience.
What Is Cal-Mag and Why Do Plants Need It?
Cal-Mag combines calcium and magnesium in a chelated, highly available form that plants can absorb instantly. These nutrients perform critical functions:
Calcium (Ca): Strengthens cell walls and promotes root and shoot development.
Magnesium (Mg): A key component of chlorophyll, helping plants convert light into energy.
Without them, plants can’t properly absorb other nutrients, especially nitrogen and potassium.
The CompleteGrow Cal-Mag Hydroponic Nutrients Fertiliser provides both elements in the correct ratios for optimal uptake — suitable for soil, coco, and hydroponic systems.
Signs of Cal-Mag Deficiency
Recognising early deficiency symptoms helps prevent long-term damage:
Yellow or brown spots between leaf veins (magnesium deficiency)
Curling or distorted new growth (calcium deficiency)
Slow growth or weak stems
Poor fruit set and blossom end rot (especially in tomatoes and peppers)
Adding CompleteGrow Cal-Mag Nutrients corrects these issues quickly. The formula is chelates-based, ensuring calcium and magnesium remain soluble and available to the roots.
How to Use Cal-Mag for Plants
Application rates:
Mix 2–4mL per litre of water for general feeding.
Apply every 2–3 weeks or as needed when symptoms appear.
Safe for use in hydroponics, soil, or foliar sprays.
When to apply:
During rapid growth (spring–summer) to support structure and photosynthesis.
When using RO (reverse osmosis) or soft water systems, which often lack calcium and magnesium.
During fruiting and flowering to strengthen cell walls and prevent nutrient lockout.
Compatible with all CompleteGrow NPK fertilisers such as:
NPK 20-20-20 All Purpose Liquid Fertiliser
NPK 4-18-38 + Calcium & Magnesium
Benefits of Using Cal-Mag Fertiliser
Improves nutrient absorption and uptake efficiency.
Prevents calcium and magnesium deficiencies.
Strengthens cell structure for healthier, more resilient plants.
Enhances fruit quality, size, and shelf life.
Boosts overall photosynthesis and plant metabolism.
Regular use of CompleteGrow Cal-Mag ensures your plants remain strong, green, and balanced — especially in demanding growing conditions.
FAQs About Cal-Mag for Plants
What is Cal-Mag used for? To supplement calcium and magnesium, improving plant structure, nutrient uptake, and overall health.
How do I know if my plants need Cal-Mag? Look for leaf yellowing, brown spots, curling, or weak growth — all classic signs of deficiency.
Can I mix Cal-Mag with other fertilisers? Yes. It blends well with most liquid and hydroponic nutrient formulas, including CompleteGrow NPK products.
Is Cal-Mag safe for hydroponics? Absolutely. The CompleteGrow Cal-Mag Fertiliser is designed specifically for hydroponic and soilless systems.
Where can I buy Cal-Mag in Australia? Right here: CompleteGrow Cal-Mag Hydroponic Nutrients Fertiliser.
Final Thoughts
Cal-Mag is one of the simplest ways to keep plants healthy and nutrient-balanced. From leafy greens to fruiting vegetables and hydroponic setups, it prevents deficiencies and promotes strong, vigorous growth.
For reliable results, choose CompleteGrow Cal-Mag Hydroponic Nutrients Fertiliser — made in Australia, formulated for performance, and trusted by growers who want greener, stronger, longer-lasting plants.












