It is a mistake to think that plants only need water to be healthy; Even the carnivorous ones – which are one of those that never have to be fertilized since their roots would burn if they did not have traps that would attract insects, they would not be able to live only with the rains. And it is that without nutrients, no living being could exist, and if we talk about plant beings, they cannot lack some of the most important: calcium and magnesium.
So if you want to know what they use them for and what are the symptoms they show when they are missing, then I will explain it to you .
What are they for?
Plants, to be healthy, need a series of macro and micronutrients. When some are missing, they become very vulnerable to both pests and diseases, as well as inclement weather (cold / heat, droughts, …). Thus, sulfur (S), along with calcium (Ca) and magnesium (Mg) are the three nutrients that, although secondary, are essential for them.
Calcium, in the form of calcium pectate, has the function hold plant cell walls together. Likewise, it is also used for the activation of enzymes and to send coordinating signals for some cellular activities.
What if it is deficient?
Plants can only absorb calcium through their roots (which will absorb it from the substrate / soil) during transpiration, since this is not a mobile element. A) Yes, Anything that slows perspiration, such as low temperatures or high humidity, can cause a deficiency of this nutrient even if the substrate or soil has adequate levels.
The parts that will notice calcium deficiency first are those that perspire little water, such as young leaves, whose edges will become necrotic, and fruits, which will turn yellowish or rot.
Magnesium is essential for many of the enzymes in plant cells to function properly. But without any doubt, their most necessary job for them is to serve as the central atom in the chlorophyll molecule. This is a pigment that makes plants -or the vast majority of them- green, and without it they would not be able to carry out the photosynthesis nor grow.
What if it is deficient?
Unlike calcium, magnesium is a mobile element; so that symptoms will be seen first on older leaveswhich will turn yellow, leaving the nerves well visible. It is not very common (of course, not as common as iron deficiency, which causes iron chlorosis), but in certain crops (Syagrus palms for example) it usually occurs when planted in clay soils.
What to do to avoid problems?
The most important is know the characteristics of the soil we haveor the substrate that we want to use, as well as the needs of the plants themselves. Thus, if we want to cultivate a carob tree (Ceratonia siliqua), we must do it in a soil with a neutral or clayey pH, since if we did it in an acid one, its roots would not have calcium availability.
As this topic can be somewhat complex, I leave you these links that will surely help you :
Anyway, if you have questions, ask.