Potassium deficiency in marijuana plants
What is potassium deficiency?
Potassium deficiency happens when marijuana plants do not get enough potassium in their nutrition. This is a major flaw, as potassium, along with nitrogen and phosphorus, are the key ingredients in their food, known by the acronym NPK.
For plants to develop well, whether they are marijuana plants or not, they need a correct balance of NPK, as well as others such as calcium, iron and manganese. Both deficiency and excess of these nutrients is detrimental to the crop, as they affect all the vital cycles of the plant, from growth to flowering.
In the case of potassium, this deficiency is rather typical for soil and outdoor crops. On the other hand, it is very rare to find it when growing hydroponics.
What are the consequences of potassium deficiency on the crop?
Both potassium deficiency and potassium excess in marijuana cultivation have detrimental consequences for the plants. This is because Potassium is essential for water to irrigate the entire plant and regulate the temperature, also to breathe and transpire, and for the enzymes that produce photosynthesis to be activated.
It also plays a key role in allowing the stems to grow strong and to generate resistance to disease, drought and temperature changes. A potassium deficient plant is a weak plant.
Finally, potassium is essential in yet another process: bud development. This is why it is in the flowering stage that plants need potassium the most. Potassium is responsible for the accumulation of carbohydrates, which play an important role in the plant’s productive capacity.
How to recognise potassium deficiency in Cannabis plants?
The sooner you recognise the deficiency, the sooner you can take measures to remedy it. Take note of these signs because it is not easy to notice, and in fact at first the plants may look very healthy.
However, the thing to focus on is the tips and edges of the leaves, and especially the lower and larger leaves. If they start to turn brown or darken, this is a bad sign. Remember that potassium deficiency affects temperature regulation and leads to leaf scorch.
If the process continues, rust-coloured necrotic spots start to appear on the leaves after a week, and the spaces between the veins turn yellow or reddish. The veins will also turn reddish, and the leaves, as they die, will first turn yellow and then grey at the end, with the tips curling upwards. These are clear signs of potassium deficiency.
When, on the other hand, there is an excess of potassium, the colour of the leaves changes to a whitish yellow, as if they had become discoloured. However, it is rare to find cases of excess potassium
How can potassium deficiency be fixed?
The safest and most convenient way is to use Canna Terra Professional Soil or other proven soil specifically for marijuana, with the ideal proportions of the different fertilisers recommended for use with this soil, i.e. Terra Vega and Terra Flores. In the event of a deficiency, an NPK corrector can be used for the different phases of the crop.
If instead of a generic product you prefer to personally adjust the amounts of nitrogen, phosphorus and potassium to the optimum values for your particular crop, you can also get the elements separately and administer the precise dosage. A more homemade technique is to use wood ashes, which have a high proportion of potassium.