The ground (or topsoil in pots) has both the function of supporting and providing nourishment to the plant. Its chemical composition is important because many species require a substrate with very particular chemical or physical characteristics (structure, drainage, water retention). If we want our plants to thrive, the topsoil it must be chemically suitable for the species (with the right proportion of elements fertilizers), prepared with care and fertilized properly.
If in the garden to make the ground nature takes care in part, with the natural decomposition of natural substances, also here among the organic fertilizers waste elements, such as pruned branches, weeds or sick plants, must never be included: the heat generated by the decomposition is not in fact sufficient to destroy the spores of any fungi and the seeds of the weeds. Where there are vegetable waste to be eliminated, it is necessary to equip yourself with a composter.
In the pots the problem does not arise and the fertilizer fertilizer must be added to topsoil. One of the things to keep in mind is that the relationship between the nutrients contained in a fertilizer it varies according to the season of administration of the fertilizer itself. For example, in the vegetative and growth phase of a plant there is generally a need for more nitrogen than the other elements (potassium and magnesium are the main ones). In the vegetative phase it is therefore necessary to choose a soil that has a ratio between the elements N (nitrogen), P (phosphorus), K (potassium) of 2-1-1, that is, a double quantity of nitrogen compared to the other elements.
L'nitrogen (N) stimulates the growth of plants and reaches the ground mainly through the rain and wind that drag the nitrogen present in the atmosphere. A beautiful dark green color of the foliage is a sign of the balanced presence of nitrogen. The potassium (K) favors the resistance of plant tissues to frost, drought and parasite attacks. The potassium content in the soil, fertilizers and plants is usually referred to as potassium oxide (K₂O) in which the single element is present at 75 percent.
The magnesium (Mg) is a fundamental element for the green color of the leaves, being one of the constituents of the chlorophyll molecule. Magnesium deficiency occurs starting from the oldest leaves, which have discolored areas usually whitish or yellowish. The sulfur (S) is one of the constituents of amino acids and proteins and therefore enters the composition of plant tissues. Sulfur deficiency occurs in plants with symptoms very similar to nitrogen deficiency, starting with yellowing of the leaves.
The football (Ca) is used in different quantities depending on the type of plant. In fact, there are calcium-loving species (especially legumes) and calcifugal species (all acidophilic species such as azaleas, rhododendrons and ericaceae). The iron (Fe) is together with magnesium one of the main constituents of the chlorophyll molecule. Iron deficiency (chlorosis) is frequently observed in plants grown in calcareous soils.
Another related article of ours that might interest you is: How to do home composting