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Calcium and Magnesium

Calcium and Magnesium

Both Calcium and Magnesium are secondary Macro Nutrients and are required by the plant in quite large amounts. They are taken up slowly by the plants and so an extra supply of these important element will improve overall health and fruit/flowering.

Calcium (ca)

Calcium relies on passive transport in water (does not require the energy to be transported) and so it has limited mobility in the plant. It is transported through the xylem and so is dependent on transpiration - low transpiration rates, cold temperatures and humidity can cause deficiencies.

Calcium has an important structural role and so a continuous supply of Calcium is required for growth. Calcium is responsible for holding together cell walls and new growth suffers from a lack of it, with improper growth and distortion in the new leaves and fruits (leaf tip necrosis, blossom end rot). Bacterial and Fungal diseases take advantage of weak cell wall when there is a deficiency in

Calcium competes with other positively charged ions such as Sodium, Potassium and Magnesium. Therefore, if you use too much Calcium, you could cause deficiencies issues of these nutrients.

Magnesium (Mg)

Magnesium is important in the production of chlorophyll for photosynthesis and capturing light to create energy for the plant to function. Unlike Calcium, the plant can move Magnesium around and take it from older leaves and utilise it within the new leaves. This causes the older leaves to yellow.

Magnesium helps the uptake and transport of nitrogen, phosphorous and sulphur.  Sometimes a deficiency showing in these elements could actually be due to a deficiency in Magnesium.


Although Grow and Bloom nutrients contain enough calcium & magnesium to keep plants healthy, problems can arise when the environmental conditions start causing stress to the plant and an imbalance in nutrient demand.

Particularly in summer, it is difficult to control grow room temperatures and humidity. If plants are showing Calcium deficiency it is important to go back to basics and firstly get the environment under control with consistent temperatures and ventilated with fresh air. Try a foliar application of VitaLink CalMag to help ease plant stress.

VitaLink CalMag can be added to the nutrient solution to ensure a continuous supply of Calcium and Magnesium is available to the plant for healthy growth. If you have not refreshed the nutrient tank since deficiencies have been noticed, do so to correct any imbalance.

It is not advised in very hard water areas to use CalMag as it could cause calcium toxicity – here it should only be added if water has been passed through an RO filter. If concentrations are too high, it may create a lock out of other nutrients.

So how can you control the growing environment better?

Many people underestimate the importance of controlling the growing environment. Check out the RAM website for the perfect products to help with this!

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