Want a Grow Sensor?
Get early access to the now.

Magnesium deficiency in cannabis: causes and solutions

Lucy Starley
December 7, 2023
5 min read
Cannabis leaf with, early signs of magnesium deficiency
Cannabis leaf with, early signs of magnesium deficiency
Download your free VPD calculator
Oops! Something went wrong while submitting the form.

Magnesium is an essential nutrient for cannabis plants, playing a vital role in photosynthesis, enzyme activation, and overall plant health. Magnesium deficiency occurs when the plant is not receiving enough of this nutrient. This leads to a range of symptoms that can affect the quality and yield of the final harvest. Magnesium deficiency can also impact the potency and flavour of the final product.

Symptoms of magnesium deficiency include yellowing of the leaves, particularly between the veins, and leaf curling or distortion. In severe cases, the deficiency can cause leaf drop, stunted growth, and reduced resin production.

Preventing and treating magnesium deficiency is crucial for ensuring a successful harvest.

In this article we will discuss:

  • The causes of magnesium deficiency in cannabis plants
  • The symptoms of magnesium deficiency in cannabis plants
  • Prevention and treatment methods to help avoid this common issue

By maintaining proper magnesium nutrition, you can help your plants reach their full potential and produce high-quality cannabis.

Disclaimer: Any information given on this site is for educational purposes only. Please ensure if you’re growing cannabis you’re doing so in accordance with the law and subject to appropriate permissions and licences of the applicable country.

The weekly newsletter for indoor growers who want to grow the best cannabis

What are the symptoms of magnesium deficiency in plants?

Magnesium deficiency symptoms in plants typically appear first in the older leaves, which may become yellow or chlorotic. This yellowing typically starts at the tips and edges of the leaves and spreads towards the centre. In severe cases, the edges of the leaves may become brown or burnt-looking. The leaves may also begin to curl or distort.

Another common symptom of magnesium deficiency is interveinal chlorosis, which is yellowing between the veins of the leaves. This can be particularly noticeable on the lower leaves of the plant.

As magnesium deficiency progresses, the plant may show signs of stress. Common signs are stunted growth, reduced resin production, and a decrease in overall plant health. Leaves may drop off the plant, and the plant may become more susceptible to disease or pest infestations.

It’s important to note that magnesium deficiency can often be confused with other nutrient deficiencies. For example,phosphorus deficiency or environmental issues, such as overwatering or pest infestations. You should closely examine your plants and look for multiple symptoms before concluding that the issue is magnesium deficiency.

In the next section, we will discuss the causes of magnesium deficiency in cannabis plants. We’ll also provide tips for prevention and treatment.

Cannabis leaf showing early signs of magnesium deficiency

How to prevent magnesium deficiency in plants

Preventing magnesium deficiency in cannabis plants starts with maintaining proper pH levels and nutrient ratios in the growing medium. Focusing on your soil quality is the best place to start.  Cannabis plants prefer a slightly acidic soil pH of between 6.0-6.5, which allows for optimal magnesium uptake. You can use pH test kits or meters to monitor the pH level of the soil and adjust as necessary.

In addition to pH levels, you should ensure that your plants are receiving a balanced nutrient mix that includes magnesium. Cannabis plants require a range of nutrients, including nitrogen, phosphorus, potassium, calcium, and magnesium, to grow healthy and strong. Choosing a high-quality fertiliser that includes magnesium can help prevent deficiencies.

Another way to prevent magnesium deficiency is to choose the right soil or growing medium. Some soil mixes are naturally high in magnesium. While others may require the addition of supplements or amendments to provide adequate magnesium nutrition.

Finally, it’s important to monitor the environmental factors that can affect magnesium uptake, such as temperature and humidity levels. Extreme temperatures or high humidity can lead to reduced magnesium uptake, so growers should strive to maintain optimal growing conditions.

By following these prevention methods, you can ensure that your plants receive proper magnesium nutrition. This is the best way to avoid the negative effects of magnesium deficiency. Later on in this article, we will discuss treatment methods for plants that are already showing signs of deficiency.

How can Grow Sensor help prevent magnesium deficiency?

Along with a soil metre, there is one other piece of equipment that can significantly help you. Environmental monitoring is a crucial task for all growers, but it’s also one that is time-heavy and complicated at times. The good news is that there is a tool that can help you to monitor and manage your whole grow space.

Equipping yourself with a grow room sensor is an excellent way to save time and people power. It also saves the associated headaches that often come with environmental monitoring!

Once installed, Grow Sensor will work quietly but diligently in the background. It will measure all sorts of environmental factors such as temperature, light, humidity and much more. This accurate and live data will then be displayed for you in easy-to-digest formats. This makes it much simpler for you to keep a close eye on your growing environment as a whole.

Access to quality data gives you the opportunity to make informed decisions about your working processes and grow space. this helps to ensure that your plants are always as happy as they can be.

This close and constant monitoring of your grow room will help to prevent deficiency issues from taking hold. If a deficiency does occur you should hopefully be alerted to it early enough to step in and take action.

How to fix magnesium deficiency in plants

Infographic showing three stages of magnesium deficiency in cannabis

If magnesium deficiency is identified in cannabis plants, there are several treatment options available. The first step is to adjust the pH level of the soil or growing medium to promote magnesium uptake. If the pH level is too high or too low, it can make it difficult for the plant to absorb magnesium. You should aim for a slightly acidic soil pH of between 6.0-6.5 to promote optimal magnesium uptake.

If nutrient imbalances are the cause of magnesium deficiency, you can adjust your fertiliser mix to include more magnesium. There are several magnesium supplements and fertilisers available on the market that can help correct deficiencies. It’s important to follow the manufacturer’s instructions carefully and not over-fertilise, as this can lead to further nutrient imbalances.

Another option is to use foliar sprays that contain magnesium. Foliar sprays are a quick and effective way to provide magnesium directly to the leaves of the plant. However, foliar sprays should be used with caution and only when necessary.  Overuse of these can lead to nutrient burn and other issues.

It’s important to note that correcting magnesium deficiency may take some time. It can take several weeks for the plant to recover. You should continue to monitor your plants and make adjustments as necessary.

In addition to treating magnesium deficiency, you should also take steps to prevent future deficiencies. This includes maintaining proper pH levels, nutrient ratios, and growing conditions. Regularly testing the pH level and nutrient levels of the soil or growing medium can help prevent deficiencies from occurring.

Treating magnesium deficiency in cannabis plants requires a combination of actions. A

Adjusting the pH level, using supplements or fertilisers, and maintaining optimal growing conditions are all part of the process. With proper treatment and prevention methods, you can help your plants reach their full potential and produce high-quality cannabis.

Cannabis leaf displaying clear signs of magnesium deficiency

Conclusion

In conclusion, magnesium deficiency is a common issue that can affect cannabis plants. However, with proper prevention and treatment methods, it can be avoided or corrected. By maintaining optimal growing conditions you can help your plants absorb magnesium and avoid deficiencies.

Identifying the symptoms of magnesium deficiency is crucial, as it can prevent further damage to your plants and promote healthy growth. Treatment methods include adjusting the pH level, using supplements or fertilisers, and providing foliar sprays. Prevention methods include maintaining proper growing conditions and regularly testing the soil or growing medium. Ita also key to ensure that the plant is receiving a balanced nutrient mix.

By following the advice outlined in this article, you can help your plants reach their full potential.

The weekly newsletter for indoor growers who want to grow the best cannabis

Share this post
Lucy Starley
December 7, 2023
5 min read

Get your free VPD & environment calculator

Perfect your environment.
Stay in the VPD sweet spot.
Ideal temperature ranges for day & night.
Prevent mould.
Induce colour.
Grow the best plants.
We care about your data in our privacy policy.
Your download will land in your inbox shortly.
Oops! Something went wrong while submitting the form.
Screenshot of our FREE VPD chart and environmental calender
Arrow
Monitor your grow rooms with the Grow Sensor. Access grow room data anywhere, anytime.
We care about your data in our privacy policy.
😉 You have been added to the waiting list.
Oops! Something went wrong while submitting the form.
The Grow Sensor hanging in front of an iPhone displaying an overview of all grows within the Grow AppArrow
Get your FREE impartial list of the best grow room sensors now. Buy the right sensor for your grow room environment.
Sort by price.
Compare features like CO2 & VPD.
Includes affordable & premium sensors.
Check availability in your location.
Make an informed decision.
We care about your data in our privacy policy.
😉 It's on the way to your inbox.
Oops! Something went wrong while submitting the form.
The grow sensor hanging from its cable.
Arrow
Grow the best plants with your FREE CO2 calculator.
We care about your data in our privacy policy.
😉 It's on the way to your inbox.
Oops! Something went wrong while submitting the form.
The grow room CO2 calculator.
Our blog

Latest blog posts

Get the latest grow news, tips and tricks here.
Grow the best - how the grow sensor handles vpd
Grow The Best

The Grow Sensor and VPD

Mastering VPD is essential for optimal plant growth. Learn how to manage it effectively now.
User avatar
Drew Cano
11 Jan 2022
5 min read
Learn your cannabis grow acronyms
Grow The Best

Learn your cannabis grow acronyms

Indoor growing has many acronyms. Learn key terms for better plant growth.
User avatar
Drew Cano
11 Jan 2022
5 min read
A grower holding some of the best soil for cannabis.
Cannabis

Best soil for cannabis: What every grower should know

Find out the benefits of using the best soil for cannabis and how to create your own perfect soil
User avatar
Drew Cano
11 Jan 2022
5 min read
Grow The Best

Embrace your grow style

Growing cannabis requires patience and learning. Explore different styles and techniques now.
User avatar
Drew Cano
11 Jan 2022
5 min read
A close up of early signs of male plant in a cannabis grow room.
Cannabis

Early signs of male plants: Learn what you need to look for

Learn to spot early signs of male cannabis plants to protect your crop's yield and quality.
User avatar
Drew Cano
11 Jan 2022
5 min read
Man inspecting cannabis plants grown outdoors on a farm
Cannabis

When does flowering start outdoors: The cannabis edition

Master outdoor cannabis flowering: Timing, tips, and more
User avatar
Drew Cano
11 Jan 2022
5 min read
A cannabis calcium deficiency in a large cannabis leaf.
Cannabis

Cannabis calcium deficiency. Causes, signs & solutions

Learn to spot, treat, and prevent calcium deficiency in cannabis for healthier plants.
User avatar
Drew Cano
11 Jan 2022
5 min read
An autoflower cannabis plant.
Cannabis

2024 guide: Autoflower vs photoperiod cannabis plants

Explore key differences and tips for autoflower vs photoperiod cannabis.
User avatar
Drew Cano
11 Jan 2022
5 min read