Cannabis Magnesium Deficiency: Causes, Prevention, and Cure

Just like human beings, cannabis plants need nutrients, too, in order to flourish and develop up until harvest. One of the common problems in cultivating weed is magnesium deficiency. Magnesium may just be a secondary nutrient, unlike nitrogen, potassium, and phosphorus, but it contributes to the development and growth of marijuana. Without it, the growing process would be useless if it weren’t for all these nutrients. Besides, it wouldn’t be that hard to maintain when proper precautions are followed. 

In this article, we will discuss cannabis magnesium deficiency. What are the common causes? What are the preventive measures? How to cure it? All these questions will be answered accordingly that you no longer have to deal with cannabis plants deficient in Magnesium. This nutrient is simple to discuss with the thought of knowing how it helps its development, particularly for photosynthesis. Read on and know more about cannabis magnesium deficiency covering its causes, prevention, and cure. 

Signs of Magnesium Deficiency in Cannabis

In identifying whether or not your cannabis plant is efficient in magnesium, you have to watch out for signs. As soon as these signs present themselves, you have to treat them immediately to prevent the cannabis plant from dying and put all the efforts to waste. Besides, it’s not that difficult to know and diagnose whether or not they are deficient in magnesium. You just have to keep an open eye for these obvious signs. Besides, cannabis plants are not that difficult to revive. There are ways on how to treat it efficiently. 

Cannabis magnum deficiency is caused by various reasons, including insufficient magnesium used or even none at all during cultivation. In some cases, overwatering cannabis can be a cause too. It will help in flushing out the nutrients such as magnesium absorbed by the plant, which puts it to no use. In other cases, check out the ph levels of the soil. If it is too low, it only explains its inability to absorb magnesium. It explains the acidity or possible magnesium lockout of the cannabis plant. 

Sign #1

The older leaves present visible veins. It would start small near the stalks and will eventually spread throughout the leaf. This will progress to discoloration. Instead of the normal color of the leaf, which is green, it will turn to yellow or rust-brown. Checking the texture, the leaves will turn flaky or brittle, but they should not be removed. 

Sign #2

The marijuana plant looks sick. Considering that the plant fails to produce chlorophyll used in photosynthesis, it is unable to absorb light to regenerate energy, which will make it look sick and unhealthy. The color is comparable to a dying plant. 

Sign #3

The dryness or dampness of the soil. Being underwatered makes the soil unable to distribute nutrients such as magnesium throughout the plant. Overwatering, on the other hand, causes the inability of the plant to distribute the nutrients because they are flushed out. 

Common Causes of Magnesium Deficiency in Cannabis

Knowing the common causes will help you in setting up preventive measures for the cannabis plant not to get sick. The most important factor that causes magnesium deficiency is the medium of the cultivation, soil in particular. The soil acts as the blood of the human body. It helps in the distribution of nutrients throughout the body. The same way goes for soil. It distributes the nutrients throughout the plant. 

  • Overwatering and underwatering of the cannabis plant. 
  • Stagnant nutrients in the soil. 
  • Too low levels of magnesium. 
  • No scheduled watering time for the plants. 
  • Unmeasured amount of nutrients infused. 
  • The inability of the roots to absorb and distribute nutrients. 
  • pH levels of the medium of growth are relatively low. 
  • Acidic soil. 

3 Ways on How to Prevent Magnesium Deficiency

Cannabis magnesium deficiency is very common during its growth. Whether you’re a newbie or an expert in the field, you should set up preventive measures to avoid it from happening. Ways on how to prevent it are not difficult, and it is easier compared to the curing process. It would be best to give a good look at the plant to check the signs it is showing too. The health of the cannabis plant should be maintained accordingly, and here are three ways on how to prevent magnesium deficiency that can help you along the way. 

Measure the pH Levels 

The pH levels along the root zone should be measured before performing anything else. This is common, especially to those growing cannabis using the hydroponic growing methods. But it is not as vulnerable as when soil is used as a medium. Regardless of the medium used, it is required to check the pH levels every now and then to prevent magnesium deficiency. When the soil or water is acidic, it will prevent the plant from absorbing the nutrients such as magnesium. 

Schedule Watering Time 

Having a schedule for watering time is highly suggested in order to prevent underwatering or overwatering them. This will allow the plant to have more time to digest and break down the nutrients to distribute throughout the plant. Overwatered marijuana plants will drown the roots and flush out the nutrients which leave it to waste. As much as possible, check out different watering cycles to see what would work out accordingly. 

Do Not Overdose the Plant 

Overdosing the plant with magnesium and other nutrients will just put these to waste. Measure the amount of magnesium infused to the plant before doing so. Not measuring it will highly affect the health of the plant and can possibly lead to faulty flowers or, worse, death. It would be best to have all the nutrients measured prior to infusion to maintain the health of the marijuana plants. Besides, you wouldn’t want to waste all these nutrients for nothing. 

The Cure Magnesium Deficiency

There are two ways on how to cure cannabis magnesium deficiency defined by two different mediums, such as soil and water. It may be challenging at first, but you will eventually come around and restore the health of the marijuana plant. Ensure that once the plant has restored its health, set up boundaries, and preventive measures for the plant not to experience it again. Check out these two ways on how to cure cannabis magnesium deficiency. 

Growing in Soil 

The required pH levels for soil should be no less than 5.5. This is relatively higher as compared to the normal pH levels of hydro mediums which should be no less than 4.5 When the levels are measured, this is one of the preventive measures to avoid cannabis magnesium deficiency from occurring. It would be best to have everything measured to avoid growing the marijuana plant is highly acidic soil. 

Marijuana plants are often grown in soil that is usually developed through hand watering. The non-required substances should be flushed with an amount of water with balanced pH levels. In addition, the nutrients should be measured accordingly before watering the plants to have them absorbed and digested by the roots right after. After infusing the plant with magnesium and water, check the pH levels of the soil again to see if it has decreased. It would be best that the pH levels are maintained to prevent cases of inability of the plant to absorb nutrients. 

One of the suggested first aids you can try to boost its health is including magnesium foliar spray to the list of nutrients the plant should have. It is made of a tablespoon of Epsom salt diluted in four liters of water that should be sprayed on the affected plants every three days. 

Growing in Hydroponics 

Growing cannabis using the hydroponics method is highly critical in acquiring magnesium deficiency. As much as possible, exert efforts in checking the pH levels of the water from time to time and change the reservoir on a scheduled basis. If the pH levels of the water are either too high or too low than 4.5, it would be best to change the reservoir with a newly mixed one. If you continue to use the old one, it will just worsen the situation of the marijuana plant and may cause death. 

Adding a supplementary amount of magnesium would not do it alone. You need to empower the roots by adding other supplements such as Epsom salts. This is another form of magnesium that is often used in marijuana plants infused as a hydro solution that keeps the substance acquainted with the water. These salts are completely organic, which makes it the number one choice among organic growers. Once the marijuana plant already normalized its growth and color, you can already manage its nutrient consumption and continue to infuse Epsom salts every watering time. 


Cannabis magnesium deficiency is very common among growers, but it doesn’t necessarily mean you have to immediately dispose of the plant. As stated above, there are ways on how you can save it and make sure it doesn’t happen again. No matter what strain you grow, it will require effort and time to grow a healthy marijuana plant delivering amazing medical and recreational effects. There’s still life even though you can already see the leaves withering.