Deficiency and excess of Calcium in cannabis plants
Calcium and cannabis
Calcium is a very important secondary nutrient given the large amount of this element that the plant needs during its entire life cycle. From the very beginning, and already in the seed germination stage, calcium takes direct part in root development and protein synthesis. It’s absorbed by the roots in the form of Ca++ ion.
It also gives support to other elements that, when combined, participate in different metabolic processes such as the creation of vitamins - in this case, vitamin B12. These vitamins will join and form part of the cellular walls of the plant tissues, making them stronger to attacks from pathogens, and keeping their cells active and vital.
The role of calcium in cannabis plants
- Calcium is necessary for the growth of the cell walls of the root system
- It ‘s an immobile element
- It enhances the decomposition process of organic matter, improving nutrient uptake by the plant
- It acts as bridge between humus and nutrients
Calcium is an element easily found in the soil, so due its high availability for the plants we usually don't find imbalances of this component except in very acidic soils.
Deficiencies can normally be more present in hydroponic crops due to the use of inert substrates (coco-coir, clay pebbles, rock wool, mapito...) or when we don't use substrate, as is the case of aeroponic systems.
In these cases, we must check that the calcium intake of cannabis plants is correct to prevent deficiencies in the early stages. Many of the fertilisers that we can find on the market have calcium, but sometimes it isn’t enough to avoid deficiencies, particularly if you are using reverse osmosis water, which doesn’t contain nutrients.
In this case (RO) you will have to prepare the nutrient solution in a different way: before adding any other fertiliser, pour two parts of calcium per one of magnesium until reaching an EC value from 0.0 to 0.3-0.4.
Visible symptoms of calcium deficiency in cannabis plants
- The youngest leaves of the plant are the first to be visibly affected
- The growth of the upper part of the plant is slowed down
- The root system is also affected, what reduces nutrient uptake
- As the deficiency progresses, the youngest leaves turn yellowish and become deformed
- Bud development is seriously reduced
To control the calcium deficiency we can perform foliar applications of Ca with a Ph of 7.2 directly on the affected leaves. We can also add calcium and magnesium to the nutrient solution, increasing the initial EC value in 0.2 points during about five days.
Calcium excess in cannabis plants
The excess of calcium is difficult to detect and causes a lock-out of various nutrients such as potassium, magnesium, manganese and iron. In different hydroponic growing systems, and when there is calcium excess in the tank it comes in contact with the sulphur of the nutrient solution, this calcium precipitates and remains on the bottom of the tank.
In this circumstance, you will have to change the nutrient solution of the tank.
Calcium is an element that is directly related to the transpiration of plants. This transpiration control comes, in essence, from the roots and the stomata, which are located on the leaves. It can happen that the stomata are closed by an excess of heat, causing a superficial burn which could be confused with a symptom of calcium deficiency.
It should also be noted that, with a deficiency of this element, plants are always more susceptible to heat stress given that calcium contributes in the protein creation, which make plants more resistant to high temperatures.
How to supply cannabis plants with calcium
As we have already mentioned, if you are using osmosis water for watering your plants you should add calcium and magnesium before adding fertilisers to the nutrient solution. Since osmosis water doesn’t contain any nutrients, your initial EC value will always be 0.0.
Fertilisers for marijuana plants already contain the necessary micro-elements for the life of the plant, but there are nutrients such as calcium or magnesium which should be present in higher concentrations - especially at the early stages - to ensure that marijuana plants have everything they need to develop properly.
Tap water with an EC range of 0.3-0.4 is perfect, since this EC level is suitable to make the mix with fertilisers and ensure right amounts of Ca and Mg in the nutrient solution. It should be noted that, depending on the grown strain, it may be necessary to add extra calcium and magnesium during the flowering stage to prevent deficiencies from the 4th - 5th week, when plants are in full bloom.
In this case, this extra supply is important so, on the one hand, plants can reduce any kind of stress during the entire crop, and on the other hand we'll harvest the best possible quality and quantity of buds. For these cases you can use Aptus Regulator during the entire crop, reducing the water needs of the plant to up to a 30% while making them more resistant to dehydration caused by high temperatures or periods of drought.
Identifying calcium deficiency in cannabis plants
Example of the condition of a plant with calcium deficiency