Plagron CalMag Pro bottles in multiple sizes on a white background

Plagron CalMag Pro 500 ml bottle on a white background

Plagron CalMag Pro 1 L bottle on a white background

Plagron CalMag Pro

Calcium + magnesium support
For soft, RO or demineralised water
Supplement only

A mineral CalMag supplement for soft water, RO water, coco and high-demand indoor growing. Plagron CalMag Pro helps correct calcium and magnesium levels before deficiency symptoms become a pattern. Use it when the water or substrate genuinely calls for extra Ca/Mg.

Quick facts

Type: CalMag supplement
Substrates: Soil / potting mix, Coco, Hydro, and Passive semi-hydro
Dosage: 0.5-1 ml/L
Frequency: As needed for soft water
Skill level: Intermediate
pH/EC: Recommended

€12,00

VAT included · plus

Please note: Most fertilizers ship separately from plants. A separate shipping fee may apply, and the final cost is calculated at checkout by order weight. Free shipping does not apply.

Size:

500 ml 1 L 5 L 10 L

Variant

4.6/5 store rating · 20,000+ customers served

Tracked shipping

Plagron CalMag Pro is used when calcium and magnesium support is missing from the water or base plan. It is a targeted supplement for coco, hydro, soft water and strong growth.

Background mineral balance

The product fits cases where water hardness, inert media or fast growth point to calcium and magnesium demand. It supports the base nutrient by making Ca/Mg availability more reliable.

Use beside the main feed

CalMag Pro belongs next to Terra, Cocos or Hydro nutrition, not in place of them. It is best chosen from water hardness, EC context or clear deficiency patterns.

Is it right for your plant?

Substrate Soil / potting mixCocoHydroPassive semi-hydro
Best for Water-grown plantsCoco-grown plantsPlants under grow lights
Helps with Water correctionMineral balanceRegular feeding
Choose another product for complete base feedinghard-water correction

Plagron CalMag Pro is a strong fit for coco, hydro, semi-hydro and soft-water feeding. It suits LED-grown foliage plants and fast-growing houseplants showing real Ca/Mg demand.

In naturally hard water, use it only when deficiency signs and water hardness point in that direction.

What's inside:

NPK Ratio: NPK 5-0-0 + 5.7% CaO + 3.3% MgO
Nutrient basis: Calcium/magnesium supplement

Plagron CalMag Pro is a calcium and magnesium supplement with nitrogen. It is used to correct the mineral background around the base feed.

The formula is NPK 5-0-0 with 5.7% CaO and 3.3% MgO. Treat it as water or medium support, not as harmless extra fertilizer.

How to use it

Use Plagron CalMag Pro up to 1 ml/L when starting water is low in calcium and magnesium. With RO water, around 0.75 ml/L can bring the starting EC toward 0.4 before base nutrients are added.

Add CalMag first, then mix the main feed and check the final solution.

➜ A few notes before measuring, mixing or applying :

Overuse can lock out other nutrients, so avoid treating it as harmless extra food. Check EC when combining with A+B feeds or concentrated base fertilizers.

Clean measuring tools because CalMag residues can crystallise.

Plagron CalMag Pro

€12,00

Frequently Asked Questions about Plagron CalMag Pro

When should I use Plagron CalMag Pro?

Use it when starting water is low in calcium and magnesium, especially with RO water, coco, hydro, semi-hydro or soft-water feeding.

Is Plagron CalMag Pro a complete fertilizer?

No. It is a calcium-magnesium supplement with NPK 5-0-0, not a full base feed. The nitrogen contribution should still be counted in the total feeding plan.

How should I mix Plagron CalMag Pro?

Add CalMag first, then mix the main fertilizer and check the final solution. With RO water, about 0.75 ml/L can bring the starting EC toward 0.4.

Close-up of hands measuring liquid houseplant fertilizer - Liquid fertilizer lets you control dosage and timing — ideal for semi-hydro setups and fast growers.

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