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Silica's Hidden Potential: Maximizing Cannabis Growth and Quality

Added 14 September 2023

When it comes to providing nutrients for cannabis plants, we typically categorize them into two groups: macro and micronutrients. While many growers are well acquainted with the three macronutrients, including nitrogen, phosphorus, and potassium (also known as NPK), micronutrients remain somewhat unexplored.

Of course, macronutrients play a huge role in plant development. However, we must not overlook the significance of micronutrients. They work quietly behind the scenes supporting plant health, stimulating growth, and enhancing the quality of cannabis yields. And, speaking of micronutrients, silica often goes unnoticed among growers.

Silica may not be an essential nutrient like other macronutrients for growing decent cannabis buds, but what sets silica apart is its ability to elevate your cannabis cultivation endeavors to new heights.

Most growers manage to grow buds that smell and taste okay, as cannabis is a fairly easy plant to grow. However, silica helps you elevate it from “okay” to spectacular without much effort from your side. 

Suffice it to say that silica doesn't merely ensure survival; it maximizes yields by producing more abundant buds with increased resistance against persistent pests and other stressors. 

Cannabis growers also agree that even a small change in yields and quality can have a huge impact. So, it's beneficial for you to understand the importance of silica in cannabis cultivation even if you’re growing decent buds. 

What is Silica?

What is silica

So, what exactly is silica? It's a compound made up of silicon and oxygen that plays a role in the growth of cannabis plants. While it may not be classified as one of the macronutrients like nitrogen, phosphorus, and potassium, it is considered a secondary nutrient. Its significance lies in its ability to enhance plant health, strengthen cell walls, and increase resistance against stressors and pests.

What is the Importance of Silica in Cannabis Cultivation?

What is the Importance of Silica in Cannabis Cultivation?

Silica, like other micronutrients, has various responsibilities. Let’s look at them in detail to understand why this ignored nutrient could help in many ways. 

1. Plant Structure and Strength

Silica aids in the development of resilient plants. When plants absorb silica through their roots and distribute it throughout their structure, it accumulates in the cell walls. This accumulation significantly reinforces the cell walls providing strength and stability to the plant structure.

As cannabis plants mature, they can become top-heavy especially when large buds begin to develop. Silica helps address this issue by offering support to stems and branches, thereby reducing the risk of breakage and instability. This increased rigidity supports the plant's ability to bear its weight and that of the developing buds, ultimately promoting more robust cannabis plants.

2. Enhanced Resistance against Stress

Furthermore, silica enhances a plant's resistance against stressors that cannabis plants often encounter. Whether it’s extreme temperatures, intense UV radiation or even underwatering, silica can reduce the damage effectively. In addition, silica helps plants retain water and survive in uncomfortable conditions. It also assists in dissipating heat when the weather’s too hot, which helps a lot to prevent heat stress. Last but not least, the reinforced cell walls act as a shield against UV radiation, lowering the risk of tissue damage while promoting healthier growth and higher yields.

3. Resistance to Pests and Diseases

Silica offers an advantage by providing resistance against fungal diseases and pests. It forms a barrier in the cell walls, making it challenging for pathogens to invade and harm the plant tissues. This enhanced defense mechanism reduces the likelihood of issues like powdery mildew and spider mite infestations. While silica alone may not completely eliminate these problems, it significantly minimizes their severity and promotes plant growth.

4. Increased Nutrient Uptake

Cannabis plants need to absorb nutrients efficiently for their well-being. Silica helps in this process as well. By facilitating the movement of water and nutrients throughout the plant, it ensures that all parts receive the nutrition required for robust growth. When cell walls are sturdy and intact, water and vital nutrients can freely flow within the plant. This improved nutrient uptake leads to plants with increased production of cannabinoids and terpenes that ultimately contribute to higher overall yield.

5. Overall Yield and Quality Improvement

Silica can influence both the yield and quality of the harvest. It strengthens the stems to make them more resistant to stress and improves absorption, allowing the plants to reach their genetic potential. It has many more advantages as you read above. Thus, a combined effect of these advantages results in the formation of larger denser buds with a higher concentration of cannabinoids and terpenes. This overall enhancement in quality makes silica an excellent choice for cannabis growers.

6. Prevention of Heavy Metal Uptake

Another advantage of silica is its ability to protect plants from absorbing metals. This plays a role in ensuring that the final cannabis product is safe and pure for consumption. For instance, the soil might naturally contain metals or contamination due to various environmental factors in certain locations. When cannabis plants absorb these metals, they can accumulate in the plant tissues and pose health risks to people who consume the buds. 

Since silica creates a barrier that restricts the uptake of metals from the soil, you can use it for your peace of mind. Plus, this is extremely important in areas where there are concerns about soil contamination with metals. 

What are the Symptoms of Silica Deficiency?

What are the Symptoms of Silica Deficiency?

Here are a few indications that suggest a lack of silica in marijuana plants:

1. Weak and Slender Stems

When cannabis plants do not receive silica, their stems tend to become weak and thin. This is because, as you already know, silica plays a role in strengthening cell walls, which contributes to plant structure and strength. Insufficient silica results in weakened cell walls, making it challenging for stems to support the weight of branches and growing buds. As the plant matures and buds grow larger, these weakened stems can bend or even topple due to all that weight and ruin the structure of the plant.

2. Reduced Leaf Vigor

One noticeable effect of a silica deficiency in cannabis plants is a decrease in leaf vigor and strength. You’ll notice that the leaves struggle to stand upright like the leaves of healthy cannabis plants. Primarily, they droop because they lack the turgor pressure to remain upright. Needless to say, this weakness makes them more vulnerable to damage from factors like wind, rain, or even the grower handling them. 

3. Vulnerable to Pests

When cannabis plants don’t have enough silica, they unfortunately become more susceptible to pest infestations. Pests typically attack weak plants. Silica forms barriers within the plant's cell walls that make it challenging for pests like aphids and spider mites to penetrate and feed on plant tissues.

If your plant has Insufficient levels of silica, the barrier becomes weak, thereby allowing the pests to attack the plants easily. Ultimately, this damages the plant and even the yields if you don’t address the issue immediately. 

4. Decreased Drought Tolerance

Cannabis plants with less silica will also display reduced tolerance to drought. Silica essentially assists the plants in retaining water in their cells. Thus, without silica, cannabis plants may struggle to cope if they experience under-watering when growing indoors. If they are growing outdoors, they will not grow well if there’s water scarcity. Plants have the ability to absorb water from the soil, but if they are deficient in silica, they will wilt and become dehydrated even if there’s moisture present in the soil. 

5. Low Resistance to Environmental Stressors

Another sign of silica deficiency is decreased resistance to stressors. Silica assists plants in reducing excess heat. This can help to reduce heat stress when the weather’s really hot. Additionally, it helps the plant withstand UV radiation to a certain extent. In the absence of silica, cannabis plants may display signs of stress such as leaf discoloration, leaf burns, and curling when exposed to environmental stresses. 

6. Reduced Growth and Yield

Although a deficiency in silica doesn’t affect the yields directly, it ultimately results in growth and reduced yields. For example, when the plant is unable to defend itself against pests and stresses and struggles to grow, you can expect a dramatic reduction in yields. This is because the plants are less likely to reach their maximum potential due to insufficient silica. 

In addition, note that the symptoms mentioned here can sometimes overlap with other nutrient deficiencies or even an imbalance in pH. Thus, you should consider several factors including the pH, nutrient imbalances, and other growing conditions. Once you determine that the symptoms are due to a silica deficiency, you can address them and promote healthy cannabis plants. 

How to Fix Silica Deficiency in Cannabis Plants? 

How to Fix Silica Deficiency in Cannabis Plants? 

Incorporating silica into your cannabis cultivation practices can greatly benefit your plants. By understanding the advantages and application techniques, you can grow more productive plants that reward you with handsome harvests. Whether you're growing cannabis in soil or hydroponics, silica is a straightforward supplement that can be used at any time. 

Here’s how you can fix silica deficiency in cannabis plants:

1. Identify the Deficiency

Before taking any measures, you must be sure that you’re actually dealing with a silica deficiency, as many other deficiencies can look similar to silica deficiency.  Look out for symptoms such as weak and thin stems that struggle to support the weight of the plants. The leaves may droop, but this could be due to overwatering as well. However, if the pH is correct and there are no other problems and the plant still displays yellowing leaves and curling, it could be a silica deficiency. Confirming these symptoms will help determine if silica deficiency is indeed the issue.

2. Select Silica Supplements

Primarily, silica supplements are available in either powder or liquid form. Choose a product that aligns with your cultivation method and personal preferences. For example, you can go with potassium silicate available as both powder and liquid. Or, you can add diatomaceous earth that's mostly silica into the soil. Ensure that the product you choose contains at least 8% silica which can be easily absorbed by the plants. 

A decent amount of silica in the product will help to saturate the soil, so it’s available to the roots. Anything less, and your plants may not benefit from it. Most importantly, follow the instructions provided by the manufacturer regarding dosage, frequency of application, and timing because excess silica can disrupt nutrient balance or even lead to toxicity issues. Always stick to the recommended dosage mentioned on the product label.

Also, note that it’s pretty easy to incorporate silica if you’re growing your cannabis plants in soil; however, it can be more complicated in hydroponics as you cannot mix silica along with other nutrients. If you’re a beginner, research the product carefully and then use it. Typically, silica works well in Ebb and Flow systems. Or, you could use foliar sprays for other hydroponic systems. Whatever you use, mix the supplement well in water, let it sit for a few hours, and then mix again. Check the pH again, adjust it, and then add it to your reservoir. 

3. Adjust pH Levels

The pH levels influence silica uptake in plants, so it’s vital that it remains in the optimal range. For soil, ensure the pH is between 6 to 7 whereas it should be between 5.5 to 6.5 for hydroponic growers. 

Another thing to keep in mind is that silica can raise the pH of the substrate or nutrient solution, making it more alkaline. Therefore, you should monitor and adjust the pH levels whenever they are out of the range.

4. Use the Supplements Properly

You can supplement silica through the roots of the plants. Simply add the silica supplement to your solution and the plants will absorb them as necessary. Remember to add silica separately, meaning you shouldn’t mix them with other nutes. This is because it can eventually lead to bioavailability problems and the plants may not be able to absorb nutrients at all. 

If you don’t want to supplement silica through the roots, you can opt for foliar sprays. Also, foliar applications work faster than others. Moreover, when you apply silica to the leaves it creates a layer that strengthens the structure of the leaves and acts as a deterrent for pests. 

5. Observe Plant Response

After adding silica supplements, closely observe how your cannabis plants respond. In a few days or even weeks, you should start noticing improvements such as stronger stems that are less prone to breaking and healthier leaves that stand upright with improved turgor pressure. Overall your plant's health and vitality will noticeably enhance. Keep monitoring their progress to ensure they improve over time.

6. Be Consistent

To prevent any silica deficiency in the future, make sure to provide silica supplements throughout your cannabis growth cycle. From the vegetative stage all the way through flowering. This prolonged application period helps your plant to accumulate silica, fortify its structure, enhance absorption, and become more resilient against stressors and pests. However, don’t overdo it as toxicity issues could arise. Simply use it like any other nutrient, and you’ll be fine. 

In addition, you can add silica to your growing medium before plating. Products like diatomaceous earth or silica sand tend to release silica slowly, ensuring long-term availability.

7. Maintain Optimal Environmental Conditions

If you want your plants to grow healthy and robust, then you must maintain optimal conditions. All you need to do is keep an eye on the temperature, humidity, and light levels to minimize stressors that could worsen symptoms of silica deficiency.

8. Implement Pest Control

If pests have infested your weakened plants due to silica deficiency, then you’ll have to address both issues. At this point, you should take measures to eradicate the pests so your plants don’t continue to become weaker. 

Summary: Silica's Hidden Potential: Maximizing Cannabis Growth and Quality

Silica is a supplement that can provide benefits to cannabis plants in various growing environments, including soil and hydroponic systems. While many growers don’t use silica, it can have a great impact on the plants. 

Not only can it improve plant health, but it also increases resistance against pests and other stressors. Most importantly, it works to strengthen the cell walls which ultimately results in a strong plant with robust branches and leaves. This is crucial for cannabis plants to produce good yields. Also, silica helps to produce high-quality buds. 

Note that silica may increase the pH of the growing medium, making it more alkaline. Therefore, you should adjust the pH and maintain a range suitable for the plants. Remember that the pH should be between 5.5 to 6.5 for hydroponic systems whereas it should be between 6 to 7 for plants growing in soil. 

Typically, silica supplements are available in both powder and liquid form, and the roots absorb it as and when they need it. Excess silica gets stored in the substrate for use. While it’s easy to incorporate silica to feed plants growing in soil, it can be slightly challenging for hydroponic systems as you cannot mix silica with other nutrients. Thus, foliar feeding may help if you have plants growing hydroponically. 

Using foliar sprays has multiple advantages as they create a barrier that prevents pests from attacking the plants. For great results, it’s best to use silica throughout the plant’s life cycle, and you can stop using it in the late-flowering stages. 


  • Are Silicon and Silica the same?

Many people use both terms interchangeably. In fact, they both sound similar, but they aren't the same in the context of cannabis cultivation. While silicon (Si) naturally exists in our environment, silica (SiO2) is a byproduct of oxygen bonding with silicon. For cannabis plants to utilize silicon effectively, it needs to be present in the form of silica. Silica is the form of silicon that plants can absorb and use in their growth processes

  • Should I add SIlica even if the soil is healthy?

Silica is not an essential nutrient. But, as mentioned before, it can make all the difference between average buds that lack luster to stunning ones that make your day. After all, it strengthens the cell walls, and when the plant is healthy from within, it will perform much better than your expectations. When you provide your cannabis plants with a silica supplement, you create an environment that helps them resist diseases and pests. Additionally, silica supplementation can improve absorption. These advantages work together to cultivate the best buds you’ve ever imagined. Many growers swear by silica and even state that they won’t ever grow cannabis without using it again. 

  • Can the plants experience silica toxicity?

While silica helps the plants immensely, yes, it’s possible for them to experience toxicity if you add too much silica. Supplementing excessive nutrients, whether it’s silica or anything else, can lead to salt buildup in the growing medium which results in a lockout. It can even damage the plant's root system. Symptoms of a lockout caused by excessive silica include browning or burning of leaf tips, stunted growth, and reduced yield. Therefore, it’s crucial that you follow the manufacturer’s instructions and use silica moderately as recommended. 



Thank you I just learned something new to incorporate very helpful.


So could you / we include a bit of diatomaceous earth mixed in with our grow-medium / compost?


@eurorack, yes! Some people even use it on their teeth, I read lol.