Potassium is an element contained in many minerals, in fact it is widespread in many soils of volcanic and alluvial origin. It can also be found contained in the organic substance. The potassium used by plants is therefore soluble, which is free in the circulating solution (water and nutrients) of the soil.
For plants, the supply of Potassium is fundamental for a correct growth as it is a fundamental element of numerous biological processes.
The main function is related to the synthesis of sugars, the formation of aromas, the coloring of the petals, fruits and vegetables.
Not everyone knows that potassium is directly involved in the transpiration of plants because it controls the opening of the leaves stomata (in practice they are like the pores of the skin, from which water vapor escapes). Furthermore, this element regulates the concentration of the sap to make the plants less subject to freezing, improves the lignification of the tissues, strengthens the plants and gives greater resistance to the effects of wind, heat and fungal diseases.
On the houseplants, garden and vegetable garden, the effects of a good potassium fertilization are highlighted by plants rich in fragrant flowers, with intense and brilliant coloring, with robust buds and less sensitive to pathogen attacks.
Nutritional elements Potassium: Potassium deficiency
Plants are not always able to find all the potassium they really need in the substrate, for a series of reasons:
· Due to the exhaustion of the reserves present in the vessel;
· For poor peat substrates and poorly drained;
· Due to excess humidity and low temperatures that limit the activity of radical absorption;
· Due to the presence of high amounts of potassium antagonists, such as magnesium.
In these cases, the plant finds itself in a situation of deficiency of the element that manifests itself with an initial yellowing of the edge of the leaf blade and can also extend inside; subsequently the affected tissues become necrotic and the leaf takes on a shower fold; the buds and the stem are slightly lignified and break easily.
Some plants also have characteristic symptoms, for example in the potato plant the leaves dry up in the margin; in the apple tree small-sized and poorly colored fruits are formed; in tomatoes there is the presence of berries with a non-uniform maturation.
In the floricultural field, the carnation presents a stunted growth with necrosis at the apex of the leaves, in the composites (asters, daisies etc.) short internodes are formed and leaves and flowers of reduced dimensions.
In bulbous plants and in particular in the tulip, the lack of potassium causes chlorosis on the leaves and often occurs in the second year depending on the reserves stored in the bulbs.
In fertilizers, Potassium (chemical symbol K) is found associated with nitrogen and phosphorus, forming the classic NPK fertilizers. On packs, potassium is present in the composition section and is conventionally referred to as potassium oxide (symbol K2O).
The additions of fertilizers with a high potassium content are advisable in the final stages of the plant's vegetative cycle and in autumn and winter, to favor the formation of intensely colored flowers and to increase resistance to cold.
The contribution of the element must be continuous, to allow the complete lignification of the tissues of the stem and of the shoots, above all in the plants with multiple cultivation cycles such as the rose.
Given the sensitivity of the flowering plants to the chlorine ion, it is advisable to avoid potassium with potassium chloride based fertilizers.