Dandaweedman

Calcium occurs throughout the entire plant.
It is used for many processes in the plant, however, calcium is most important for the growth process.
It has a regulating effect in the cells and contributes to the stability of the plant.

Calcium is not a very mobile nutrient in plants and it is, therefore, important that a sufficient amount of calcium is always available in the root environment, so that it will be continuously available for absorption by the plant.
In the case of a calcium deficiency, the older, larger leaves will show the first symptoms of deficiency.
It often affects the leaves just above the bottommost leaves just like with a magnesium deficiency.

A calcium deficiency is recognisable at the occurrence of yellow/brown spots,
which are often surrounded by a sharp brown outlined edge.
In addition, the growth is curbed and in serious cases the result of this is a greatly reduced yield.

The yellow/brown spots surrounded by a sharp brown outlined edge that are found on the leaves, are characteristic of a calcium deficiency.
The symptoms of a calcium deficiency often appear quickly, within one or two weeks of the first spots being visible on the older leaves.
The spots usually start as small, light brown specks that increase in size over time.
After about 2 weeks, the older leaves show ever increasing spots and the spots also often appear at the edge of the leaves, like a potassium deficiency.
Be that as it may, the differences between a calcium deficiency and a potassium deficiency are in most cases easily distinguishable.
With a calcium deficiency the spots have a sharp outline and do not start
exclusively at the edge of the leaves.
Lag in development is often already noticeable within a week into deficiency.
The older leaves die off slowly and yellowish spots may appear around the dead spots.
The bloom is also slowed down and the number of pistils remain low. The pistils also turn brown prematurely.

A deficiency can occur by:
- Insufficient or incorrect fertilisation.
- An excessive amount of ammonium, potassium or magnesium int he soil/unsoil mix.

What to do?

If the EC value of the substrate or the soil is too high, it can be easily rinsed out with pure and if necessary acidified water.
If the soil contains insufficient amounts calcium, then it can be applied in the form of dolomite, hydrated calcium sulphate, or lime nitrate.

Be careful with fertilisers containing chloride.

Additional Calcium can be applied through the nutrient solution by means of liquid lime fertilisers such as a calcium nitrate solution.
Acid soil often contains insufficient amounts of lime. Good potting soil and Coco substrates are already limed
Lime, in its free form, can be easily absorbed by the plant.
As lime in the plant is not very mobile, the symptoms will not disappear where it concerns older leaves.
The development, however, from that moment on will take a normal course,
without showing any further deficiency symptoms.

In addition to the problems caused by calcium deficiency in the plant, problems can also arise due to calcium deficiency in the soil.
Calcium deficiency in the soil often goes hand in hand with acidification of the soil.
As a result of the acidification of the root environment, phosphor amongst other elements becomes less available for the plant, while various heavy metals become more available, which can lead to the
poisoning of the plant (for example aluminium, manganese and
nickel).
Too much calcium damages the plant and results in curbed development and dark green plants.
An excess of calcium can further lead to Manganese, Zinc and
Magnesium deficiencies.
In some cases it can also to copper deficiency

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