Do your cannabis plants need Cal-Mag?


What is up everyone welcome back 

As you can probably already tell today we're going to be talking about your plants need for cal-mag. We're going to go over the importance of cal-mag and also if or when it needs to be supplemented.

We'll also look at what a cal-mag deficiency and excess would look like.

Full Grow Guides On Our Youtube Channel

FREE Grow Course How to Grow Weed At Home

Looking for high Quality Seeds? Use code: Hydro10 to Save 10% 

Inside Hydro Nutrient Needle 

Before we get started  if you don’t already go and subscribe to my YouTube channel so you can be  apart of the community. Also, any products being used or talked about in this post will be linked. 


Why Cannabis Plants Need Cal-Mag: Understanding the Importance of Calcium and Magnesium

Cannabis plants are known for their high nutritional requirements, and among the essential nutrients, calcium and magnesium play a crucial role in the growth and development of these plants. Without adequate amounts of cal-mag, the plant may experience stunted growth, discoloration, and reduced yield. This article will explore the reasons why cal-mag is essential for cannabis plants and the benefits of providing this nutrient.

Calcium for Cannabis Plants: Calcium is an essential macronutrient that plays a crucial role in the development of the plant's cell walls, root growth, and overall structural stability. In the absence of calcium, the plant will experience stunted growth, and its leaves will yellow, leading to a decrease in the overall yield. Furthermore, calcium helps in the absorption of other essential nutrients such as nitrogen and phosphorus, which are necessary for healthy plant growth.

Magnesium for Cannabis Plants: Magnesium is another crucial macronutrient that is essential for cannabis plant growth and development. This nutrient is the central component of chlorophyll, which is responsible for the plant's photosynthesis. A deficiency of magnesium will cause the leaves to yellow, and this may result in reduced yield and stunted growth. Furthermore, magnesium plays a critical role in the formation of new cells and in the process of converting light energy into chemical energy.

Cal-Mag for Cannabis Plants: Cannabis plants require a balanced combination of calcium and magnesium to grow and develop properly. Cal-mag is essential for proper plant metabolism, and it helps in the formation of new cells and in the process of converting light energy into chemical energy. Additionally, cal-mag plays a crucial role in the overall health and growth of the plant, and it helps to prevent nutrient deficiencies and other growth problems.

Benefits of Providing Cal-Mag to Cannabis Plants:

  • Promotes healthy growth and development of the plant
  • Prevents yellowing of leaves due to nutrient deficiencies
  • Increases yield and overall plant health
  • Supports proper plant metabolism
  • Aids in the absorption of other essential nutrients

In conclusion, cal-mag is an essential nutrient for cannabis plants, and its absence can lead to stunted growth, discoloration, and reduced yield. By providing cal-mag, you can ensure that your cannabis plants receive the essential nutrients they need to grow and develop properly. For best results, be sure to use a balanced cal-mag supplement and follow the recommended dosage.

What is cal mag?


Cal mag is a term for any calcium magnesium additive

That you use along with your base nutrients

Calcium is important for plants to grow properly


Plants use calcium use to strengthen the foundation of the cell walls and the efficiency of photosynthesis and we all should know how important that is

So it can be argued that this is one of the most important element for your plants health

There are many different forms of supplements like cal-mag, calimagic or organic things like dolomite lime and worm castings. I don't use organic things personally so I cant really add much about that but I know people these have worked for.


Now that we know its important, is a supplement necessary?

Well it depends on the medium

If you're growing in soil,

You may already have calcium and magnesium in your soil depending on the quality, high quality soils wont need much supplementing if any at all.  If the soil you're using is high quality and the nutrient line your using  has some cal-mag already in it then there's a good chance you wont need to supplement at all.


Same thing goes for dwc or hydro like me. If you're using a base nutrient that already has cal-mag in it Like the one I use, GH flora series 3 part and tap water then you probably wont need to supplement because tap water has cal--mag in it already it just needs to be broken down to be absorbed by the plant.

If you're using r/o water than a cal-mag supplement may be necessary because the water will be pure with no cal calcium.


Just as a side note the cal-mag found in tap water is not readily available for your plant due to the fact it takes some time to break down where as the cal-mag found in a supplement you would buy is already ready to be absorbed by your plant immediately.




Alright so we know generally when we would need to supplement or not but your plant could tell you otherwise

Lets look at a deficiency / excess

Alright guys that's pretty much it, supplement accordingly but don’t stop there ALWAYS READ YOUR PLANTS and adjust your supplementation if necessary.

Importance of Monitoring Cal-Mag Levels:

Monitoring the calcium and magnesium levels in your cannabis plants is crucial for ensuring their health and vitality. Calcium and magnesium play vital roles in various physiological processes, including cell structure, enzyme activation, and nutrient uptake. Regularly testing the nutrient solution or soil pH and conducting periodic tissue analysis can help you identify any deficiencies or excesses in cal-mag levels. By staying proactive and attentive to your plants' nutritional needs, you can prevent potential problems and optimize their growth potential.

Signs of Cal-Mag Deficiency:

Identifying signs of cal-mag deficiency early on is essential for addressing nutrient imbalances before they escalate. Common symptoms of cal-mag deficiency in cannabis plants include yellowing leaves (especially between the veins), necrosis (death) of leaf tips or margins, and overall stunted growth. Additionally, you may observe interveinal chlorosis, where the leaf veins remain green while the areas between them turn yellow. Regularly inspecting your plants for these indicators allows you to take corrective action promptly and prevent further damage.

Signs of Cal-Mag Excess:

While cal-mag deficiencies are more common, excessive levels of calcium and magnesium can also pose problems for cannabis plants. Symptoms of cal-mag excess include leaf tip burn, leaf curling or cupping, and reduced overall plant vigor. In severe cases, nutrient imbalances can lead to nutrient lockout, where the plant becomes unable to absorb other essential nutrients, further exacerbating the issue. Understanding the signs of cal-mag excess helps you avoid over-supplementation and maintain a balanced nutrient profile for optimal plant health.

Correcting Cal-Mag Imbalances:

When faced with cal-mag imbalances, it's essential to take corrective action promptly to restore your plants' health and vitality. Depending on the severity of the deficiency or excess, you can adjust your nutrient solution's composition, pH levels, or application frequency. Consider supplementing with a high-quality cal-mag product specifically formulated for cannabis cultivation, following the manufacturer's recommendations for dosage and application methods. Additionally, incorporating organic amendments such as dolomite lime or gypsum into the soil can help replenish depleted calcium and magnesium levels over time.

Importance of Water Quality:

Water quality plays a significant role in nutrient delivery and uptake in hydroponic systems and soil-based grows alike. Factors such as pH, hardness (mineral content), and contaminants can affect the availability and absorption of calcium and magnesium by cannabis plants. Test your water source regularly and invest in appropriate filtration or treatment methods if necessary to ensure optimal growing conditions. Providing clean, balanced water is essential for maximizing nutrient uptake and preventing nutrient deficiencies or imbalances.

Benefits of Balanced Nutrition:

Maintaining a balanced nutrient regimen, including adequate levels of calcium and magnesium, is essential for promoting overall plant health and maximizing yields. Balanced nutrition supports robust root development, efficient nutrient uptake, and enhanced resistance to environmental stressors such as heat, drought, or disease. By providing your cannabis plants with the essential building blocks they need to thrive, you can achieve healthier, more vigorous growth and ultimately a bountiful harvest.

Community Engagement:

We invite you to share your experiences and insights regarding cal-mag supplementation in the comments section below. Join our community of growers to exchange tips, ask questions, and support each other on our journey to successful gardening. Together, we can learn and grow as we cultivate our passion for cannabis cultivation.

Call to Action:

If you found this information helpful, don't forget to subscribe to our YouTube channel for more in-depth tutorials and grow guides. Stay connected with our community and explore additional resources on our website to take your growing skills to the next level. Happy growing!