Plagron CalMag Pro | Calcium & Magnesium Supplement

Plagron CalMag Pro – Calcium & Magnesium Supplement

£7.99

Size 500ml 1 Litre 5 Litres 20 Litres Syringe Only

Type: Mineral
Mineral feeds are dissolved minerals your plant can use straight away. They're fast-acting and precise, but it is possible to overdo them, so stick to the dose.

The Most Overlooked Ingredient in Your Watering Can

Here's an odd truth: the purer your water, the hungrier your plants can get. Rainwater, filtered water, reverse osmosis (RO) water and soft tap water are wonderfully clean, and almost completely empty of calcium and magnesium. Plants notice. Rusty brown spots, yellowing between the leaf veins, weak or twisted new growth: plenty of "mystery" problems are simply a plant quietly asking for minerals its water never gave it.

Plagron CalMag Pro puts them back. It's a concentrated liquid calcium and magnesium supplement, blended in a balanced ratio so the two minerals don't compete with each other for uptake. One millilitre per litre turns empty water into the perfect base for whatever you feed next.

Why It Works

Stronger plants from the inside: calcium builds sturdy cell walls, helping stems carry heavier leaves, flowers and fruit.
Greener leaves: magnesium sits at the very heart of chlorophyll, keeping foliage deep green and photosynthesis humming.
Better roots, better uptake: supports root development and helps plants absorb the rest of their nutrients.
Tougher against stress: well-built cell walls stand up better to stress and disease.
Made for LED lighting: plants under LEDs transpire less, so they naturally draw up less calcium. CalMag Pro closes the gap.
A tiny dose goes a long way: at 1ml per litre, a single 500ml bottle treats up to 500 litres of water.

For Houseplant Lovers

Watering with rainwater, a filter jug or softened tap water is a kind thing to do for fussy plants like Calathea, Maranta, ferns and Alocasia, but it leaves their water mineral-free. The same goes for anyone growing under an LED grow light. Add CalMag Pro to your watering can at 1ml per litre and your plants get the calcium and magnesium they'd been missing, without you changing anything else.

One exception: carnivorous plants such as Venus flytraps and Sarracenia need genuinely mineral-free water, so leave CalMag Pro out of their can.

For Growers

CalMag Pro is a base supplement for RO and soft water in soil, coco and hydro, and can be used at every watering. It's typically used to lift the starting EC of RO or soft water (usually to around 0.3–0.4) before your base nutrients go in.

Pairs with: Plagron Coco A&B. You'll get 10% off the A&B when you buy the two together.
Dose: a maximum of 1ml per litre of water (1:1000).

Rose's Pro-Tip: Shake the bottle, then add CalMag Pro to your water first and stir before adding anything else. Mixing concentrated nutrients straight into each other can make them lock up and drop out of solution. Minerals first, base feed second, extras last.

Which Size?

500ml: treats up to 500 litres of water, ideal for a houseplant collection
1 Litre: treats up to 1,000 litres, the everyday grower's size
5 Litres: treats up to 5,000 litres, great value for larger setups
20 Litres: treats up to 20,000 litres, the lowest price per litre for big grows
Syringe Only: for measuring that 1ml dose accurately