Why You Should Be Using Calcium and Magnesium Supplements

Are Calcium & Magnesium the Most Underrated Plant Supplements?

Calcium/Magnesium supplements are often referred to as calmag, calmag has a wide range of benefits from improving general plant health to correcting nutrient deficiency's. 

Calmag supplements are a crucial part of any nutrient regimen, especially in countries that have low EC/Soft water with low levels of calcium present. 

Low EC water is also known as soft water, the majority of New Zealand uses soft water the EC value usually sits at between 0.2EC-0.4EC. When the EC of your water is below 0.4EC we recommended using calmag products to help your plants absorb nutrients and to prevent deficiencies.

Another use case for calmag is when using Coco Coir as a substrate, Coco has a much higher calcium demand than soil or other substrates, you will need to ensure you have enough calmag present to avoid deficiencies. When growing in coco coir, It is recommended to always use a calmag supplement, or at minimum, a fertiliser that is high in calcium & magnesium if you want optimum plant health.

Calcium and Magnesium are a crucial part of any plants diet, almost all plants will see some sort of health benefits from using a calmag supplement. Calcium can improve your plants cell structure, stress resistance, internal nutrient/water transport and overall growth patterns. Magnesium is also crucial to help your plants photosynthesize at higher rates, it will improve fruit quality and taste and it will support energy transfer and enzyme activation within a plant. 

While nitrogen, phosphorus, and potassium often steal the spotlight, calcium & magnesium are just as vital for strong, resilient, and productive plants. Whether you’re growing vegetables, fruit trees, hedges, or houseplants, supplementing with CalMag can mean the difference between average growth and exceptional results.

Here are some crops that will benefit from calmag supplements:

Vegetable Garden

Tomatoes & Peppers - Prevents blossom end rot

Leafy Greens (lettuce, spinach, kale) - reduces tip burn & supports strong leaf growth

Cabbage, Broccoli, Cauliflower (brassicas) - prevents leaf edge necrosis & boosts head formation

Root crops (carrots, beets, potatoes) - Improves root development, firmness, and storage life

Trees, Fruit Trees & Hedges

Citrus (oranges, lemons, mandarins) - Helps fruit set & reduces fruit drop

Apples & Pears - Improves storage quality

Stone Fruit (plums, peaches, cherries) - Better fruit firmness, shelf life, and flavour

Avocados - Improves skin quality and reduces fruit drop

Hedges & Ornamentals - Encourages strong stems and greener, healthier foliage

House Plants

Tropical foliage (Monstera, Philodendron, Calathea, Ficus, Peace Lily, etc.) - Keeps leaves greener, prevents yellowing, improves overall vigour

Succulents & Cacti - Prevents thin or weak growth, supports water/nutrient balance

Flowering houseplants (African Violets, Orchids, Anthuriums) - Improves bloom longevity and intensity

Product Recommendations

We have a range of calcium and magnesium supplements

From Floraflex's Calmag to Bio Diesels Marine CaMg+ there are many options to meet your specific plants requirements.

Bio Diesels Marine CaMg+ is perfect for plants that require high nitrogen because of the added nitrogen and calcium (8-0-0 npk ratio). Marine Calmag is great as a foliar spray, deficiency corrector or even as a vegetive booster 

Floraflex's Calmag, Flairforms CMX, Green Planet Procal & ISN Rejuvenator - are ideal for plants that require less nitrogen while still maintaining calcium and magnesium intake