Hello my friend I will say like my colleagues may I give you some explanations which will allow you to increase your knowledge and skills in cannabis grow ๐
Yellowing of the leaves in houseplants or trees and shrubs in the garden can be caused by several factors: excess watering, deficiency, insecure sunlight, temperature variations, drafts ... Simple gestures make it possible to correct this very common appearance defect.
The symptoms are easily identifiable: a part of the leaves has yellow spots that spread quickly and more or less uniformly, then fall, and the vegetation is slowed down. First, rule out a possible disease or parasite: stains rather than yellowing of the entire leaf, yellowing and deformation of leaves, rather evoke a parasite (insect, virus, fungus, bacterium ), and the presence of small insects, fine canvases covering plant organs or mites is easily detected with careful observation of leaves and stems.
Do not worry too much if only a few leaves are yellow, especially if it is old leaves: even for plants with evergreen (ornamental plants, olive, ficus, citrus fruits such as orange or lemon tree, oleander ...), the leaves are constantly renewed and it is normal that the older ones turn yellow.
Causes related to the substrate A deficiency of the substrate frequently causes yellowing of the foliage. This is especially true for potted plants, which are more vulnerable to soil depletion. It can act of a deficiency in:
Iron: we talk about chlorosis. The yellowing, induced by the disappearance of chlorophyll, begins at the edge of the leaves and extends towards the veins, which remain green. All plant species can be reached.
Magnesium: same symptoms as chlorosis.
Potassium: especially for trees and shrubs grown in very calcareous soil, very acidic, or light texture.
Phosphorus: all plants may be concerned, but this type of deficiency is very rare in gardens. It is usually young leaves that turn yellow. One possible cause is the leaching of phosphates in acidic soil or caused by heavy rains. It is mainly heavy soils, clayey or peaty, or formed on a ferruginous crust, which are conducive to phosphorus deficiency.
Nitrogen: all plants. Poor or sandy soil, or limited soil volume (pots) is mostly involved. It can also be a phenomenon of nitrogen hunger, usually transient.
In each of these cases, the solution is to provide a suitable fertilizer or amendment.
Here is my friend a complete answer now you know everything ๐
Good luck for your grow ๐ฑ
May the force be with you ๐ช