Cal-Mag Deficiency During Flowering And How To Supplement

Last Updated on October 26, 2022 by Sam

If you start to notice cal-mag deficiency during flowering you’ll need to act fast to save your plant’s bloom. During flowering, plants need more magnesium and calcium because of bud production. This is a key productive stage in a plant’s life that requires lots of nutrients to sustain the bloom stage. Calcium and Magnesium are two of the most important secondary nutrients. They are a little less important than the primary nutrients – N, P, K).

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These two minerals through secondary are vital to the biological processes in a plant. Let’s see what each mineral does.

Calcium Benefits to Plants Magnesium Benefits to Plants
Gives cell wall more rigidity Assists in enzyme production
Allows plants to have a strong structure and shape Helps plants make chlorophyll
Makes cell walls healthy Helps plants grow into  full maturity
Helps the healthy cell wall to regulate the proper transfer of other nutrients Assists in the absorption and transport of essential nutrients like phosphorous and iron.
It is vital for cell division and formation in plants  
Activates specific enzymes in plants  
Helps transport the organic molecules in plants  
Highly essential for the development of healthy fruit structure  

Signs Of Cal-Mag Deficiency During Flowering

It is not easy to detect Cal-Mag deficiency in the early stages of a plant. Thus, it is important to act as soon as you detect the first sign. First signs appear in the lower leaves of the plant. The tips of the leaves curl upwards and turn brown. The brown spots increase in size and number starting from the lower to the top part of the plant. The youngest leaves on the top part of the plant also get brown spots with discoloration of veins.

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How To Supplement Cal-Mag Deficiency During Flowering

Water is one of the essential requirements for all plants. Did you know water is one of the supplements for these secondary nutrients – calcium and magnesium? Natural water contains abundant calcium and magnesium as dissolved minerals. Plants should be able to get these two nutrients in plenty from the soil/water itself. Tap water also contains these two secondary minerals. You don’t have to worry about using natural water only. Soft water has a low pH with minimal minerals in it.

If you live in an area with low pH, you will have to look for Cal-Mag supplements for your plants. Hard water contains high concentrations of calcium and magnesium. Using this water means you don’t need to add any Calcium or Magnesium supplements. Treated water requires Cal and Mag supplements addition. Because the distillation process removes the good minerals from the water.

How Much Calcium And Magnesium Should You Use?

You can make a homemade cal-mag supplement using Epsom salts (Magnesium sulfate) and Calcium nitrate. Mix 2 parts calcium to 1 part magnesium. You will need 6g Calcium Nitrate and 4.5g Epsom salts per gallon of water. In specific situations, you might need to adjust the nutrient levels to fit your type of deficiency. If you buy a pre-mixed cal-mag supplement, you will get the right recommended mixture. Stick to those levels for the best results. Remember, excess use of these supplements can be bad for your plants!


How do you fix Cal-Mag deficiency in flowers?

Calcium is important for the development of new flower buds. Magnesium is also needed to make a healthy flower. If you don't correct it, you will get sickly flowers.

Calcium is one of the most important minerals for plant growth. Calcium helps the plant to grow and bloom. Calcium deficiency will affect the formation of cell walls and cause the flowers to be weak and deformed and cause the plant to grow slowly and may even die. The easiest way to correct Calcium deficiency is to use a Calcium rich fertilizer. You can find Calcium enriched fertilizers at any local nursery or garden center.

Magnesium is an important element for the development of new flower buds. Magnesium deficiency will cause the blooms to have a pale, sickly appearance. Magnesium deficiency will also cause the plant to grow slowly and may even die. The easiest way to correct Magnesium deficiency is to use a Magnesium enriched fertilizer. This will help the plant to get the Magnesium it needs. You can find Magnesium enriched fertilizers at any local nursery or garden center.

How do you add Cal-Mag to plants?

Cal-Mag is a liquid that will raise the pH of your soil. To apply Cal-Mag to your plants, mist them thoroughly with water. Apply 1/4 teaspoon of Cal-Mag per gallon of water. Mist again after 24 hours.
Repeat this process once a week for a month. Cal-Mag is a combination of calcium and magnesium. It can be used on any type of plant except some species of mint. Cal-Mag is particularly useful in preventing stress and disease and in improving the health of plants. The amount of Cal-Mag used should not be more than 1/4 teaspoon per gallon of water. If you use too much, it will cause burns or discoloration.

Can I mix Cal-Mag with nutrients?

You can add nutrients (Vitamin D, Iron, etc.) to a pre-made calcium-magnesium supplement.

Can you use too much Cal-Mag?

Yes, it's possible to over apply. I don't know the exact amount that's bad but it's definitely possible. It won't hurt plants as long as they're not in a nutrient-poor soil or a high pH soil. The more Cal-Mag you use the more of the other nutrients will be left in the soil. If you use Cal-Mag and then fertilizer, it's recommended to add fertilizer at least 24 hours after applying Cal-Mag.

What are the symptoms of calcium deficiency in plants?

Calcium is an essential macronutrient for plant growth and development. It is involved in a number of physiological processes including cell division, wall construction, seed germination and fruit ripening. Plants can also acquire calcium from the soil, but most of it is absorbed by the root system. Calcium is stored in the leaves and stems as chlorophyll helps to bind calcium to photosynthetic pigments.

The symptoms of calcium deficiency vary depending on the species of plant. Some plants will show no visible symptoms of calcium deficiency while others may display stunted growth and reduced biomass. In some plants, the leaves may appear yellow or have a bronze coloration. This is due to the loss of chlorophyll which binds calcium to photosynthetic pigments. The roots may also appear yellow. In other plants, the leaves may appear withered, curling at the edges. In some cases, calcium deficiency may cause the plant to produce abnormal growths, such as leaf or flower buds, or the formation of leafy shoots.


In most cases, these two supplements can be easily available in water and soil. But in exceptional cases, supplements are required. Cal-Mag supplements are available to buy. But you need to pay attention to the labels. Get something that consists of cal and mag only. Be sure to get a supplement that does not contain other nutrients. Supplements that contain nitrogen and other nutrients bring a risk of over-feeding. This is dangerous to your plants!