Potassium deficiency guide
It is necessary for all activities having to do with water transport and the opening and closing of the stomas. Potassium takes care of the strength and the quality of the plant and controls countless other processes such as the carbohydrate system.
About potassium in short
What is it and what does it do?
- Potassium takes care of the strength and the quality of the plant.
- Controls countless other processes such as the carbohydrate system.
What do you see?
- Dead edges of the leaves.
- What can you do?
- In case the EC in the substrate or soil is high, you can rinse it with clean water.
- Add potassium yourself.
Symptoms of a deficiency
Evaporation is reduced if there is a shortage of potassium. A consequence is that the temperature in the leaves will increase and the cells will burn. This occurs mostly on the edges of the leaves, where normally, evaporation is highest.
Development of a deficiency
- Tips of the younger leaves show grey edges.
- Leaves turn yellow from the edge in the direction of the veins and rusty-coloured dead spots appear in the leaves.
- The tips of the leaves curl up radically and whole sections of the leaves begin to rot. The leaves keep on curling and ultimately fall off.
- An extreme shortage produces meagre, unhealthy-looking plants with strongly reduced flowering.
Reasons for a deficiency
- Too little, or the wrong type of fertiliser.
- Growing in potassium-fixed soils.
- An excess of sodium (kitchen salt) in the root environment, as sodium slows down potassium intake.
Solutions for a deficiency
- In case the EC in the substrate or soil is high, you can rinse with water.
- Add potassium yourself, either in inorganic form: dissolve 5 – 10 grams of potassium nitrate in 10 litres of water. In acidic soils, you can add potassium bicarbonate or potassium hydroxide (5ml in 10 litres of water).
- Add potassium in organic form: add a water solution of wood ash, chicken manure or slurry of manure (be careful not to burn the roots). Extracts of the grape family also contain a lot of potassium.
For your information
Potassium is absorbed quickly and easily by the plant. In a hydroponic system results get visible within several days. Potassium supplementation by leaf fertilization is not recommended.
Too much potassium will cause salt damage, calcium and magnesium deficiencies and acidification of the root environment!