How To Diagnose And Treat Magnesium Deficiency In Cannabis

Cannabis plants require a number of nutrients to grow and thrive. The primary nutrients cannabis requires include nitrogen, phosphorous and potassium - sometimes referred to as NPK. But to have strong, healthy plants, there is another nutrient that must be present as well: magnesium. As a matter of fact, all plants need magnesium to grow strong and that's why we're going to focus on it here. We want to make sure that you grow plants that give you the highest yield and the best quality weed possible.

Cannabis Grown Inside is More Susceptible to Magnesium Deficiency

Magnesium deficiency is most commonly noted on plants that are grown indoors. Since many indoor growers use hydroponics systems, the farmer has to make sure they give the plants the right amount of nutrients.

Some people forget to give these plants all the nutrients they need. While the NPK combination carries some other micronutrients, magnesium included, in many cases it is not enough and you would be required to add more micronutrients yourself.

Plants grown outdoors don't suffer from this condition as much. The soil contains a lot of nutrients, both macro and micro and the plant is able to naturally extract magnesium in this way.

Why Magnesium? Why Not Other Micronutrients?

You might be asking yourself, 'why isolate only magnesium? Is it the only micronutrient cannabis needs?'

As previously stated, the plant needs a number of nutrients, both macro and micro. It requires iron, magnesium, zinc, copper and others to thrive. The reason we have isolated magnesium will become pretty evident as you read on.

You will need to understand the role that magnesium plays in the growth of a plant to be able to appreciate its relevance and importance. Magnesium is absorbed into the plants through the roots. In the plant, the mineral is wholly responsible for the process of photosynthesis. In simple terms, you could say that magnesium is responsible for the green coloring of the plant.

In more detailed terms, chlorophyll, the element that captures the energy of the sun to assist the plant in photosynthesis can't do this without the presence of magnesium. You will find magnesium in the enzymes of chlorophyll molecules.

Symptoms of Magnesium Deficiency in your Cannabis Plant

You will need to check for symptoms of magnesium deficiency in your plants now and then, particularly during the early stages and if you are growing the plant indoors.

There are a number of basic symptoms to look for:

  • older leaves become yellow between their veins and around their edges;
  • the leaves turn purple, red or brown in color;
  • the leaves wither;
  • the tips of the leaves start dying out;
  • the leaves start curling under;
  • the leaves become spotty and speckled;
  • the leaves fall off and die;
  • the plant itself dies (hopefully you don't get to this level).

From the symptoms observed, the deficiency effect starts from the lower leaves and works its way up. You need to keep an eye on these lower leaves so that you can detect the disease and cap it before it spreads. It takes time, energy and money to grow a healthy cannabis plant, so you don't want to lose them to a disease you can control.

How to Fix Magnesium Deficiency in Cannabis Plants

If your plant is already lacking in magnesium, you can control this by adding some nutrient boosters to the soil or water solution you're growing your plants in. Some of these boosters are important in increasing the quantity and quality of your yield in the long run.

Different strains could use different forms of boosters, but generally they all work in the same way. You can purchase them from your local dispensary. Alternative options include Epsom salts, dolomite lime and magnesium sulfate. Both magnesium sulfate and Epsom salts are soluble in water, making them the best choice as the plant will absorb them faster.

Is There a Relationship Between a Plant's pH Ratio and Magnesium?

The pH ratio of a plant is the measure of the acidity or alkalinity of the plant. The cannabis plant tends to lean a bit on the acidic side at about 6–6.5 pH. If the roots of the plant are not in the right pH, it can prevent your plant from absorbing the magnesium it needs.

You will need to check the pH of the soil before you plant to guarantee better and stronger plants. If you have already planted your cannabis in soil that doesn't have the right pH levels, you can always change this by adding nutrients as needed. You may want to consult a professional grower at too.

Once you've corrected the pH balance, you will be able to see almost immediate effects to your plant's health. The leaves will stop drooping and stand firm and strong. The coloring will also change from yellow and brown to green. This process that might take a number of days, so just be patient.

When growing cannabis indoors, always ensure that you use the recommended spacing between plants so that these plants are able to absorb the minerals and nutrients needed without much competition. The controlled environment that indoor growing offers is a great way to ensure healthy and high quality weed as there is little or no contamination present.

Despite this, higher yields and better-tasting weed are often found in outdoor crops. Outside cannabis plants have the room they need to grow healthy and vibrant. They are able to absorb different elements from the soil, including magnesium. Plants grown indoors get only what you give them and since space is limited, your yield will also be limited.

Even though magnesium is not the only important micronutrient for growing great cannabis, it is as an essential one. Plants just can't do without it and hence we need to ensure that the uptake of magnesium nutrient in our plants is solid and consistent.

Cannabis for Beginners - Do I have to smoke?


In the past few months, the stream of alarming news about the dangers of vaporizer cartridges has put some cannabis consumers on high alert. Since March, more than 2,000 people have gotten sick, and 40 people have died from illnesses related to vaping (VAPI, or vaping associated pulmonary injury). It is believed that the large majority of those who had become ill had used THC oil carts bought from illicit markets.

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