If you’ve been dealing with plants for a while, maybe today’s song sounds like Chinese. Do not worry; I’ll explain it simply so that everyone understands it. What is this about iron chlorosis? In other words, it is nothing more than the yellowing of the leaves caused by an iron deficiency.
In the case that you are a regular reader of the blog, this matter will not be a novelty for you. We have already touched it before, specifically when talking about acidophilic species and also highlighting the essential nutrients for plants. By the way, two readings highly recommended understanding better what we are going to talk about.
Need for minerals in plants
As a summary for the newcomers, it is worth noting that, in addition to water, light and carbon dioxide and oxygen from the air, all vegetables require at least 13 minerals to survive. In the absence of any of them, the plant would begin to show signs of deterioration.
Nitrogen, phosphorus, and potassium are the most demanded by plants – by themselves, they account for almost three-quarters of the total requirement in minerals – and along with calcium, magnesium, and sulfur (also numerous), form the macronutrients of the plants. For this reason, they are considered basic and indispensable in the composition of many fertilizers. You could interpret from this that others are less important, but you would incur an error.
Symptoms of lack of iron
Not to be less required, the lack of a micronutrient will go unnoticed. The plant will manifest it, of course, from the first moment. In the case of iron, the initial symptoms will appear in the young leaves, evidencing a notable loss of intensity in the coloration. Its green will turn little by little too yellow, in all the limb except for its nerves that will remain green. It is also frequent its arbitrariness, appearing in some branches and others not.
The most similar symptoms are those caused by the lack of magnesium and also by the lack of manganese. However in magnesium, as with nitrogen, they would be shown earlier in old leaves.
It will be with manganese that you will have more difficulty discerning. As in the case of iron, the signs will be noticed first in the young leaves, although here they will also keep green strips surrounding the nerves. That will be the subtle difference. To top it all, there are often several shortcomings at the same time, complicating everything.
Why there is a lack of iron
The iron deprivation in the plant is not usually due to a real absence in the soil since it is required in minimal quantities. The most common is that, for some reason, it is blocked and can not be assimilated by the roots.
The usual cause of the blockage is an inappropriate substrate pH (too high for the plant). If the support that holds it has a basic pH (above 7) it will surely be affected. Iron will then have problems to dissolve in the water.
The fork between 6.5 and 7 (neutral pH) is preferred by most species. It is the range where all the nutrients are correctly assimilated.
This rule is altered, however, in acidophilic plants, with a preference for soils with low pH. If you grow for example Japanese maples, heather, hydrangeas, rhododendrons, azaleas, gardenias or camellias, these should range between 4.5 and 6 or else they will suffer from ferric chlorosis. Others, such as citrus, without requiring such a low pH, also like a slightly acid soil. Do you want some orange, lemon or mandarin healthy? Well, it uses a 6.5 environment substrate.
How to find out the pH of the substrate? You have some gadgets at your fingertips, which will give you an approximate orientation. The most affordable and easy to use are these meters to puncture the floor or the usual test strips that indicate a color code.
Water and fertilizer can also raise the pH
Repeated irrigation with heavy waters (with an excess of mineral salts) will also be an inconvenience for delicate species. If the tap water contains too much lime, better use other options (rainwater, mineral or distilled), or it will end up alkalizing the substrate. Another alternative is to lower the pH, adding a few drops of lemon juice or vinegar.
For the same reason, in the acidophilic plants, the usual fertilizers with high concentrations of salts are not suitable. You must manage other special ones for them: fertilizers for acidophilic plants.
How to solve ferric chlorosis
So far you have seen how to identify iron chlorosis, distinguishing it from the others, and how to make it so that it does not appear in your plants. With a bit of luck, it will be enough, and you will only end this article out of curiosity. But, if you had identified the symptoms, nothing happens. You will see that the world is not over either. Next, I explain how to solve them.
In such a situation, the fertilizers with habitual formulas will not work, since it is not a question of simply adding iron. With the disadvantage of an alkaline substrate, the mineral would not reach the plant. You must use iron chelate, as an emergency measure. Of course, later you’ll have to take care of the problem. The mode of application of the iron chelate will vary depending on its arrangement and concentration. There is to spray directly on the leaves, to dilute in irrigation water or presented in granules (to spread on the substrate). You decide which one is most comfortable for you, but follow the manufacturer’s instructions.