Canna - Fe Iron Plus

A single-element iron supplement for vegetative growth and flowering, added directly to the reservoir and stable within normal pH margins.

With iron the pH matters more than the dose

Of all the nutrients, iron is the most pH-sensitive, which makes it the element where feeding more most often fixes nothing.

Free iron in water oxidises and precipitates as rust-brown iron hydroxide as soon as the pH climbs. Above roughly 6.5 that happens fast, and above 7 there is practically no freely available iron left. The iron is still in your pot, just in a form the root can do nothing with. Adding more simply means more precipitate.

That is why an iron product uses chelated iron. A chelate is a molecule that wraps around the iron ion and shields it, so it cannot oxidise and stays in solution at pH values where free iron gave up long ago. That is also what CANNA mean by stable within normal pH margins: the bottle is built to keep working across the range you actually grow in.

So the practical order is the same as with phosphorus. If you see iron symptoms, measure your pH first and correct it. If you are above 6.5 that is almost certainly your cause, and feeding more is wasted.

Where an iron deficiency shows

Iron is not relocated within the plant. That means symptoms appear in the youngest leaves while old leaf keeps looking fine, just as with calcium.

The picture is characteristic: young leaves going yellow to almost white while the veins stay sharply green. That fine green vein pattern on a pale leaf is the clearest way to tell it from magnesium, where the yellowing sits low down instead.

The plant needs iron to produce chlorophyll and as part of a range of enzymes. It is not in the chlorophyll molecule itself, but without iron the molecule does not get made, and that is why a deficiency looks so bleached.

In use

This bottle may be added directly to the reservoir. Of the seven CANNA single-element fertilisers it is one of only two with no mixing restriction, which makes handling simpler than with the rest of the range.

For use in both vegetative growth and flowering, in soil, coco and all hydroponic systems.

Technical Specifications:

• Type: single-element iron supplement, liquid
• Manufacturer: CANNA
• Action: chelated iron, stable within normal pH margins
• Phase: vegetative and flowering
• Substrate: soil, coco and all hydroponic systems
• Mixing: may be added directly to the reservoir
• Volume: 1 litre
• Packaging: 100% recyclable polyethylene, free of PVC and cadmium

Frequently asked questions

I am feeding iron and still see yellowing.
Look at your pH. Above roughly 6.5 iron precipitates and stops being available, however much you add.

How do I tell it from a magnesium deficiency?
Iron shows in the youngest leaf with sharply green veins on a pale background. Magnesium starts low down.

What is chelated iron?
Iron wrapped and shielded by a molecule so it cannot oxidise, keeping it in solution at pH values where free iron has already precipitated.

Can it just go in with my other feed?
This one may be added directly to the reservoir. That is not true of most of the other bottles in this range.

Will existing yellow leaf recover?
Barely. Iron is not relocated within the plant, so judge the result on the new growth.