Hy-pro - Cal-Mag

A supplement of calcium, magnesium and micro-elements, dosed at 1 to 2 ml per litre. Added to the water before the base nutrients go in.

Why growers suddenly needed Cal-Mag once LED arrived

Cal-Mag was a fringe product for twenty years and now appears in almost every schedule. That is not because plants changed but because the lamp did, and the mechanism behind it is worth understanding.

Calcium moves through the plant differently from most elements. It travels upward with the water stream, root to leaf, and that stream is driven by transpiration: the leaf gives off water vapour and in doing so pulls fresh water, with dissolved calcium, up behind it. No transpiration means no transport.

A sodium lamp radiated a good part of its energy as heat, straight onto the leaf surface. That leaf ran warm, transpired hard and drew calcium up as a matter of course. LED is far more efficient and gives off considerably less radiant heat. The leaf stays cooler, transpires less, and the calcium stream upward slows down.

The result is a deficiency that is not in the tank but in the transport. You can have calcium in abundance in your feed and still see the symptoms, and feeding harder will not help.

What else you can do about it

Topping up is one side of it; keeping transpiration going is the other, and the second costs nothing.

Do not let humidity climb too high in flowering; in damp air the leaf has nowhere to put its water and transport stalls. Keep air moving across the canopy, because a leaf in still air sits in its own layer of moisture. And do not let the gap between leaf and room temperature get too small: under LED that gap is naturally narrower than you were used to under sodium.

Skip those and part of your Cal-Mag stays in the tank instead of reaching the leaf.

Dosing

Add 1 to 2 ml per litre of water, according to need. Mix it thoroughly through the water first, before adding your regular base nutrients: that way it dissolves fully and you avoid local concentrations that could react with your feed.

For use in both the vegetative and flowering phases, and safe alongside all common hydro and soil systems. Besides calcium and magnesium it supplies micro-elements, which are equally absent when growing on soft water.

Available sizes

Technical Specifications:

• Type: calcium and magnesium supplement with micro-elements
• Manufacturer: Hy-Pro
• Dose: 1 to 2 ml per litre of water, according to need
• Order: mix thoroughly through the water first, then the base nutrients
• Phase: vegetative and flowering
• Application: all common hydro and soil systems
• Intended for: soft water and grows under LED

Frequently asked questions

Why do I need Cal-Mag under LED and not under sodium?
Calcium travels with the transpiration stream. LED gives off less radiant heat, the leaf stays cooler and transpires less, so less calcium gets pulled upward.

I already feed Cal-Mag and still see symptoms.
Then look at transport rather than dose. High humidity and still air suppress transpiration and with it the calcium stream.

Why does it go in before the base nutrients?
So it dissolves fully and no local concentrations form that could react with your feed.

How does it differ from a bottle without micro-elements?
Besides calcium and magnesium this one supplies micro-elements, which are also missing when growing on soft water.

Can I feed it all cycle?
Yes, it is intended for both the vegetative and flowering phases.