When it comes to nutrients, N, P&K love the spotlight! It is easy to ignore calcium and magnesium. Don't do this - both are macro nutrients. Without them, the plants will not survive.

 The good news is that it is easy to add calcium and magnesium. A good CalMag will do the trick. In fact, the addition of CalMag is a quick solution to the most common shortcomings, as most CalMag products also contain iron and nitrogen.


 Calcium is key to plant growth and structure! Plants use it to connect cell walls - it thickens the stems and strengthens your structure. This makes it difficult for pests and pathogens to penetrate the walls of plant cells.

A big reason for adding calcium is that it helps prevent other common deficiencies. Why? Calcium is involved in many metabolic processes that affect the absorption of other nutrients, such as nitrogen (N), magnesium (Mg) and potassium (K).

It is well known that calcium helps plants cope with the stress of temperature and humidity. How? Helps the stomach function (small pores on the leaves). These pores are used for gas exchange and transpiration. Lack of calcium can really confuse stomach processes, making it harder for plants to cope with the environment.

Main advantages

  • Prevent other nutrient deficiencies
  • Thickens cell walls
  • Strengthens the structure of plants
  • Balances the absorption of magnesium and potassium
  • Prevents pests
  • Counteracts the withdrawal of calcium in coconut

Causes of deficit

No energy is needed for absorption - plants absorb calcium passively as they absorb water. It is then moved up into the plant by transpiration. If the humidity in your room is not very high and the plants do not absorb or lose water through the leaves, calcium deficiency often occurs.

Calcium deficiency is most common when grown in coconut. Despite all its benefits, coconut is known to retain calcium (Ca) and, in some cases, nitrogen (N).

To make matters worse, coconut also releases potassium (K). Too much of this can lead to calcium deficiency, as the two are chemically similar.

Calcium deficiency can also occur in hydroponic systems. Especially if you use soft or RO water with common essential nutrients. To prevent problems, use a mild aqueous formula that contains more calcium.

As with all nutrients, you can get calcium deficiency through malnutrition or the wrong ratio of nutrients. Adding too much potassium and magnesium and having too much sodium will lead to calcium problems.

Signs of deficiency

Calcium is immobile. Once deposited, it remains where it is. This means that signs of deficiency appear mostly on newer leaves:

  • Necrosis of younger leaves
  • Brown and crunchy growing tips
  • Deformed or bent leaf tips
  • Rusty brown spots on older leaves



You will find magnesium in chlorophyll - green things that absorb light. Plants need it for photosynthesis. So if you have high intensity lighting (600-1000W), you really don't want magnesium deficiency.

Plants also use it when they expend a lot of energy and photosynthesize.

Make sure you have enough magnesium during periods of strong fruiting and rapid growth.

Main advantages

Vital for photosynthesis

Crucial in periods of rapid growth

Low pH can cause magnesium deficiency - it can precipitate from your nutrient solution and be inaccessible to your plants.

Excessive watering can also cause magnesium deficiency. As the medium becomes saturated, the oxygen content decreases, which causes anaerobic conditions — this lowers the pH.

If you notice magnesium deficiency, be aware of what could be causing it. A good fertilizer should have enough magnesium in it - you usually get deficient only if you do not feed the plants enough or if you overdo it with supplements high in potassium, calcium or ammonia nitrogen.

Signs of deficiency

Unlike calcium, magnesium is a mobile nutrient - it can be transported to where it is needed. Disadvantages show more in the middle and older leaves:

Yellow leaf tissue, but veins remain green (early)

Brown rusty stains with burnt spots (later)

From growshop-bg.com we recommend the use of Atami CalMag for all types of systems and plant environments. However, if you already use CANNA products, it would be best for you to get a CANNA CalMag Agent or experiment with their individual bottles. Last but not least, Bloom CalMag is one of the few products on the market that you will never go wrong with.