Organic vs Synthetic Fertilizers for Growing Cannabis

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Added 28 August 2023

What’s your favorite dish — a cheesy burger or a healthy salad? You probably chose the cheesy burger (can’t blame you; it’s so tasty!), but it’s also quite unhealthy. 

But, does it make sense to eat only salads every day? 

No. In fact, you can indulge in burgers dripping with cheese occasionally, as a cheat day once in a while is healthy for most people. 

A similar approach can be applied to cannabis plants. Your cannabis plant has two options: healthy organic fertilizers or efficient synthetic fertilizers. Many cannabis growers will argue that organic ones are better and synthetic ones should be avoided at all costs, and vice versa. 

So, what should you do? Read on to find out which is the best type of fertilizer for your cannabis plants. 

Why Fertilizers are Crucial for Cannabis Plants

Why Fertilizers are Crucial for Cannabis Plants

Cannabis is called “weed”, but invasive weeds don’t grow big, bushy flowers. Similarly, if you let your cannabis plant grow like a weed, it will not grow big or strong, and the yield will be of low quality with airy buds, low potency, and a subpar flavor profile. To grow a healthy cannabis plant, you need to give it a lot of nutrients. 

The way to give your cannabis plant all the nutrients it needs is via fertilizers. Remember, cannabis requires three macronutrients — nitrogen, phosphorus, and potassium — in large quantities, so a good fertilizer should be rich in these three nutrients. It should also contain all the other micronutrients like zinc, calcium, magnesium, etc. to support your plant’s metabolic activities. 

With a fertilizer that contains both macronutrients and secondary nutrients, your cannabis plant can flourish, growing big and strong. The resulting plant will be tall with thick foliage, and it will grow big flowers full of resin and flavor. So, you must give your cannabis plant the right kind of fertilizer.

However, there are two different schools of thought when it comes to cannabis fertilizers: synthetic and organic fertilizers. This is a dilemma that many cannabis growers face at the beginning of their careers, but which type of fertilizer is right for you? Read on to find the answer.

What are Synthetic Fertilizers for Cannabis?

What are Synthetic Fertilizers for Cannabis?

Synthetic fertilizers, as the name suggests, are lab-produced products that contain all the necessary nutrients to sustain cannabis plants. These fertilizers are produced using chemical processes and aren’t organic or natural in most cases. For example, nitrogen in synthetic fertilizers is often produced with the Haber Bosch process, and phosphorus and potassium are created from purified minerals. 

Many cannabis growers choose synthetic fertilizers for how easy they make the entire process of feeding the plants. You don’t have to wait for them to release the nutrients or rely on nature for nutrients; with synthetic fertilizers, you know exactly what your plants are going to get. 

Synthetic fertilizers are manufactured through a process that extracts specific nutrients and combines them in precise proportions. Sure, these nutrients may be derived from naturally occurring sources, but they are further processed to refine the chemicals present in them. This process allows the chemicals to attain their pure state, making them immediately available to plants. 

Like organic fertilizers, there’s a wide range of synthetic fertilizers, ranging from all-purpose to slow-release. You only have to look at the label to determine the type of fertilizer you’re using. If you’re buying from a reputed company, you’ll see a lot of information about the ratios and respective weight percentages. Typically, this is represented as NPK, which is nothing but Nitrogen (N) Phosphorus (P), and Potassium (K) symbols.

Synthetic fertilizers combine nitrogen, phosphate, and potassium in specific compositions that can be readily absorbed by plants. Unlike organic fertilizers that rely on the microbes present in the soil for conversion, these man-made nutrients provide immediate assimilation for cannabis plants.

Cannabis plants, like almost all other plants, require micronutrients for healthy growth as well, but they are not accessible to plants when they are in their basic form as there may be differences in ion charges — whether positive or negative — which prevent them from penetrating the plant structure. 

To overcome this challenge, the chelation technique is employed. The ions are surrounded with chelates to alter the charge, thereby allowing the transfer of micronutrients to plants. 

However, you have to keep in mind that although the nutrients are absorbed by the plants quickly, improper application can negatively impact plant growth and root health. If you’re using synthetic fertilizers, start with small quantities, and you won’t even have to increase much because a little goes a long way. 

But, you must fertilize the plants regularly to avoid deficiencies. In addition, they can compromise soil health as they have limited ability to support microorganisms, unlike organic options.  

Now, you’re probably thinking — do synthetic fertilizers kill microbes?

This is a question that has sparked debates over the years. Most organic growers argue that synthetic fertilizers kill bacteria and microbes. However, some studies point out that synthetic fertilizers, when used correctly, don’t have a great impact on microbes. 

Although organic treatments do show an increase in both fungi and bacteria, extensive studies have examined the content after the use of both synthetic and organic fertilizers, and synthetic fertilizers have not shown a decline in microbes. However, other beneficial worms like earthworms may get irritated due to chemical fertilizers and try to move out of the soil. 

That said, organic fertilizers are better than synthetic ones because chemical fertilizers aren’t eco-friendly. 

Benefits of Synthetic Fertilizers

Not all cannabis growers prefer synthetic fertilizers, but there’s a place and time for them, for sure. For many growers, synthetic fertilizers are the way to go for the benefits they offer. Here are some of the benefits of using synthetic fertilizers.

1. Controlling the Dosage is Easy 

Cannabis is a peculiar plant, and for the best results, you need to give it the right amount of nutrients. Any more and it will experience a nutrient burn and any less and the yield won’t be any good. Here, synthetic fertilizers make it very easy to dose your nutrients while feeding the plant.

Synthetic fertilizers come with precise nutrients, so you never have to second guess. In fact, quality fertilizers list all the nutrient quantities right on the packaging, which is not the case with many organic fertilizers where you have to rely on guesswork. This benefit minimizes nutrient deficiencies or burns by ensuring your plant only gets what it needs. 

2. Synthetic Fertilizers are Easy to Use 

The second biggest benefit of synthetic fertilizers is that they are quite straightforward to use. You can purchase them in various forms like pellets, liquids, and granules, and they are water-soluble. All you need to do is follow the manufacturer’s recommendations to dose them while mixing them in water. And since they are so consistent, you don’t have to second guess or calculate anything. 

3. They Act Quick

Organic nutrients are often bound up in various materials like compost or manure, but that’s not the case with synthetic nutrients, which are free-form. So, when you administer them to your plant, they don’t have to be broken down or processed, and they can be quickly absorbed by the roots. 

This is especially helpful when your plant is suffering from a nutrient deficiency as you don’t have to wait for nutrient release. You can give your plant synthetic nutrients and they will get absorbed quickly. They’re a quick fix. 

4. They are Affordable 

Organic fertilizers can sometimes be cheap, like when you maintain a compost pile, but store-bought organic fertilizers are often expensive. On the other hand, synthetic fertilizers are much cheaper. You can find them in most horticultural stores in various types without breaking the bank, which works perfectly fine for small-scale growers. 

Downsides of Synthetic Fertilizers

Synthetic fertilizers are precise, quick-acting, and affordable, but they have their own downsides, which can often be deal-breakers for many cannabis growers. Here are the downsides of synthetic fertilizers. 

1. Nutrients May Build Up Over Time In the Soil

Synthetic fertilizers may damage the soil by causing a salt buildup in the soil. If you use them for a long time, salts building up in the soil will affect the medium’s pH levels, making the soil unhealthy for the roots to be in. Due to the wrong pH, your plant will fail to absorb all the nutrients, which will only make matters worse. 

2. You Need to Apply Them Regularly

Synthetic fertilizers must also be applied regularly as they tend to either be absorbed fast or leach from the growing medium. So, when using them, you need to be on your toes to make sure the soil does not run out of nutrients and your plant’s nutrient demands are always met. This can be a burden not only on your routine but also on your wallet. 

3. Nutrient Toxicity is Common

Since you’ll be applying synthetic nutrients often and they work so fast, there’s always a risk of overfeeding your cannabis plants. Plus, if you are not careful preparing the fertilizers, you may end up giving your plant too much nutrients since these products are highly concentrated, leading to overfeeding, nutrient burns, and toxicity. 

4. Many Synthetic Products Aren’t Eco-Friendly

This is a deal breaker for many cannabis growers who want to keep their operations as eco-friendly as possible. Synthetic fertilizers aren’t the most eco-friendly and the processes used to manufacture them may not always be sustainable. Plus, these fertilizers often run off into the local soil or groundwater and waterways, damaging the ecosystem within. For example, fertilizers can deplete oxygen in rivers or kill fish.

What are Organic Fertilizers for Cannabis Plants?

In agriculture, the term "organic" is centered around the idea of "living matter." However, it's quite common to come across misunderstandings about its meaning and implications especially when it appears on product packaging. So, when you see a label termed organic, it means that the product is made from living matter. Thus, people prefer organic foods that are grown without the addition of pesticides or synthetic fertilizers. 

From a scientific standpoint, “organic” differs a little. In this particular context, organic refers to the chemical definition, which denotes compounds that are characterized by carbon-hydrogen or carbon-carbon bonds present in the product. Note that even synthetic fertilizers could contain carbon, which is organic; however, synthetic fertilizers are not considered organic. 

The difference between fertilizers and organic fertilizers is that synthetic ones use chelated nutrients that are nothing but elements enclosed within molecules. Simply put, they are manufactured synthetically and lack the organic attributes of their natural counterparts. In comparison to organic fertilizers, synthetic ones don’t contain as many micronutrients and don’t do much to improve the fertility of the soil. However, they are engineered in such a way that they dissolve easily in water and provide quick nourishment to plants. 

Organic fertilizers are not lab-produced or chemical-based; these plant- or animal-based fertilizers are derived from natural sources, thanks to microorganisms. Essentially, microbes process various organic compounds, and during this process, various minerals are released. These minerals can easily be absorbed by the plants. 

The most common organic fertilizers include manure, compost, bone meal, fish meal, bat guano, seaweed, gypsum, etc. You can either prepare these at home if you have the resources or you can purchase them in the store, although they’ll be a bit more expensive than synthetic fertilizers. 

If a manufacturer wants to label his product as organic, it needs to adhere to the Principles of Organic Agriculture established by the IFOAM in 2005, rather than solely relying on the presence of organic compounds, within the fertilizer.

Such principles act as a measuring stick to assess whether the product in question can be used for organic farming. Organic fertilizers, which are created through the breakdown of matter, serve as prime examples of slow-release nourishment for plants. They go beyond providing plant nutrition, enrich the soil, and support a sustainable ecosystem that relies on countless microbes. These microbes play a role in breaking down material into nutrients that plants can readily access.

Many cannabis growers prefer organic nutrients because they can enhance the flavor and aroma profiles of the cannabis buds, but on the flip side, these fertilizers aren’t suitable for hydroponic setups that don’t use soil. They need microbe-rich soil to work properly. 

Benefits of Organic Fertilizers

Organic fertilizers are wonderful products that can make a massive difference in your cannabis operation. Here are some of the best benefits of organic fertilizers for cannabis plants.

1. They’re Rich in Nutrients

Organic fertilizers are loaded with all the essential macro- and micro-nutrients required by the cannabis plants for healthy growth. Unlike synthetic fertilizers, organic fertilizers like manure or compost contain a variety of nutrients, so your plant can have access to all the nutrients it needs. 

2. Improves Soil Environment 

Organic fertilizers don’t work directly for the cannabis plant; instead, they are processed and broken down by microorganisms, the byproduct of which is nutrients. So, organic fertilizers act as food for these microbes. Add these fertilizers to the soil and they will breed beneficial microbes, which will drastically improve your soil’s environment, leading to a richer soil food web. 

At the same time, the presence of beneficial microbes in the soil will also increase the soil’s quality. When soil is devoid of microbes, it appears to be dusty and doesn’t have great water retention, but microbes can make the soil more spongy and firm, giving it the right amount of aeration and water retention capabilities. This can further benefit your cannabis plant in various ways by making sure it is not parched or exposed to pathogens. 

3. Less Nutrient Waste 

As mentioned above, organic fertilizers improve the water retention of the soil, so when you apply them, the nutrients don’t wash away with the water. Instead, they stay intact in the soil to be absorbed by the cannabis plants. This is not the case with synthetic fertilizers that get washed away by water quickly. 

Plus, since these fertilizers release nutrients slowly, the soil will always have nutrients without any risk of washing off even during heavy showers. Even the nutrients that are released by the fertilizers are not left sitting in the soil; they are constantly being processed by the rich soil food web, which further protects them from being washed away. 

As a result, you will not end up spending so much on organic nutrients in the long run and these fertilizers will last a lot longer in the soil compared to synthetic fertilizers. That means fewer applications compared to synthetic fertilizers.

4. Fewer Chances of Nutrient Burns 

Organic fertilizers release the nutrients slowly, so there are fewer chances of too many nutrients being released into the soil. As a result, you don’t have to worry much about giving your plant excess nutrients, causing toxicity or burns. This also protects the soil by preventing salt buildup, so your plants will not face nutrient problems due to wrong pH, either. 

5. Better Tasting and Smelling Cannabis Buds 

Many cannabis growers choose organic fertilizers for one reason — they improve the buds’ flavor and aroma profiles. The buds get their unique flavor and smell from volatile hydrocarbons, also known as terpenes. Organic nutrients help produce more terpenes in many plant species. So if you want your buds to taste and smell better, organic fertilizers are the way to go. 

6. Organic Fertilizers are Sustainable 

Organic fertilizers are not produced using harmful chemical processes and they don’t wash away into the local water bodies and damage life. What’s more, organic fertilizers can even help make your home more sustainable. 

For example, if you maintain a compost pile, you can add your garden and kitchen waste to the pile instead of sending it to your local landfill. You can even go a step further and source these fertilizers from local farms, use wood chips, or get creative with them. All in all, organic fertilizers are better if you want to keep your operation eco-friendly and sustainable. 

Disadvantages of Organic Fertilizers

Organic nutrients offer a ton of benefits, but they still have some downsides. Here are some of the biggest downsides of organic fertilizers.

1. They are Slow Release Fertilizers

Organic fertilizers release their nutrients slowly, and while this is a good thing for many growers, it can sometimes be a problem when time is of the essence. For example, if your cannabis plant is suffering from nutrient deficiency, you need to add nutrients fast so your plant can get the much-needed nutrient boost. 

Organic fertilizers fail in this regard because they release nutrients slowly, over multiple weeks or months. This is where synthetic fertilizers offer a better benefit as they are quick acting, giving your plant the nutrient boost it needs when it needs. 

That said, some users report that using strong organic sources can help you get rid of deficiencies. For example, chicken manure or even rabbit manure provides nitrogen pretty fast, but there’s a risk of burning the plants if you use too much. In addition, the manure must be well-composted or rotted to work as expected. Although this works well for nitrogen, it’s a guessing game if your plant needs other nutrients urgently. 

2. Organic Fertilizers Invite Pests

When using organic fertilizers, you’ll likely add a layer of mulch over the soil to protect the microorganisms while they munch on organic matter and release nutrients. However, this environment is also the perfect breeding ground for pests and harmful pathogens. 

Often, organic fertilizers invite pests like ants, slugs, mice, and much more to the mulch-sheltered environment. While this is usually not a problem, sometimes, their numbers can get out of hand and they can bring various problems and some of their friends with them. 

Some organic fertilizers, like compost, may also be contaminated if they are not maintained well. They may introduce mold or fungi spores, pest eggs, weed seeds, and much more, which can also create various problems in your garden, ranging from pests to fungi.

3. Nutrient Content Isn’t Consistent

Unlike synthetic fertilizers, organic fertilizers like compost or manure don’t contain consistent levels of nutrients. One batch of compost can be rich in NPK while the other may not be. And since they release nutrients slowly, it can be hard for new growers to figure out the problem until it’s too late. 

4. Organic Fertilizers are Costly 

While making organic fertilizers at home is almost cheap, most of us don’t have the space or time for it. You’ll likely purchase them, which can be expensive — just like any other produced with the “organic” label. 

Fortunately, organic fertilizers aren’t marketing scams, they are properly organic and will work as intended, but they’ll come at a cost. For example, bags of mulch can cost hundreds of dollars! The best bet is to prepare your own organic fertilizers. 

5. They Aren’t Easy to Use

Organic fertilizers often come in large bags of manure or massive compost piles, which are tricky to apply. It’s gonna require some elbow grease — you’ll have to rake your soil, apply it carefully, and cover it up with mulch. You can still find organic fertilizers in pellet forms, but that’s rare and expensive. 

Which Is Better: Organic or Synthetic?

Which Is Better: Organic or Synthetic?

Your cannabis plant’s yield quality and flavor rely on the fertilizer you use. This, along with the various pros and cons of organic and synthetic fertilizers, can make it difficult to choose from either of the two. But you can make the decision by keeping two factors in mind. 

First, consider your cannabis plant’s aroma and flavor profile, which is affected by the type of fertilizer you use. As mentioned earlier, organic fertilizers boost terpene content in the buds, which improves the bud's flavor and aroma. Synthetic fertilizers don’t do the same, and many growers even state that they can harm the buds’ flavor and aroma instead. 

This is why you’ll have to flush your grow medium regularly when using synthetic fertilizers as they can cause salt buildup in the soil and affect the taste of the flowers. You’ll even have to flush the plant before harvest to flush any fertilizers from the plant. 

Second, consider the time and money you are willing to invest in feeding your plants. Organic nutrients are expensive and will require some time and effort, but synthetic fertilizers are easy to use and quite cheap comparatively. 

You should also consider the environmental impact, the benefit of beneficial microbes, and your preferences, but the two mentioned above are the primary factors that make or break the decision. Based on it, you can choose between synthetic and organic fertilizers. 

Thirdly, plants don't have a preference for where their nutrients come from, whether it's organic or synthetic. Their natural ability to absorb what they need remains unaffected by the manufacturing process or origin. However, as a grower, it’s your responsibility to understand the differences between these categories so you can make good decisions and provide nourishment for your plants. 

This simply means that you should pay attention to the labels and NPK ratio, which is usually expressed as a percentage of weight. The NPK ratio tells you about the composition of the fertilizer. For example, an N 20 means that 20% of the package weight is nitrogen. Synthetic fertilizers often have NPK numbers because they are more concentrated. While it's generally true that powders are more likely to be synthetic and liquids more likely to be organic, there are exceptions to this guideline. 

Combine the Two Fertilizers

You can take this a step further by combining organic and synthetic fertilizers. Both have unique benefits and can complement each other. For example, you can use organic fertilizers throughout the growth cycle as a primer and use synthetic fertilizers as supplements, whenever needed. 

For example, if you use organic compounds, they will slowly release nutrients into the soil on their own. However, sometimes, they may not release all the necessary nutrients, wherein you can add synthetic fertilizers to make up for the deficit. So, consider striking the right balance between both types of fertilizers so you can exploit the benefits from both while minimizing their risks. 

Summary: Organic vs Synthetic Fertilizers for Growing Cannabis

Fertilizers are food for your cannabis plants, and you have two types to choose from: organic and synthetic. Organic fertilizers are natural, eco-friendly, and slow-releasing, and synthetic ones are lab-produced, efficient, precise, and sometimes not so eco-friendly. But don’t think of them in black-and-white terms — the middle ground is what you should aim for in most cases.

It’s better to use both in your cannabis garden. Let organic fertilizers be the bread and butter of your cannabis plant and synthetic ones be a treat or medicine once in a while when your cannabis plant requires a nutrient boost. However, you can always choose just one as per your preferences. 

There is no hard and fast rule as to which fertilizer you should use. Do your research, consider the pros and cons of both, and choose a fertilizer that works best for you. Your cannabis plant will grow well under the right conditions and fertilizers. 


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Following the metaphor of the hamburger, my plants and I eat varied foods without pause throughout our lives, we do not lack anything, we eat vegetables, meat or fish, we do not eat industrialized foods, nor bottled vitamins, nor labeled food supplements. , not even if the label is "Organic" or "Bio", etc. I don't buy fertility, I build it with my hands. Let's move from theories to practice I friendly challenge anyone who grows with synthetic fertilizers to grow against my techniques and homemade organic Bio fertilizers, the one with the most production wins the challenge, the only conditions are, the same strain, the same pot size and the same growth period vegetative. I give the winner 30 seeds to choose from my collection... let's play!
@AlienScrOG, Only growing with substrate
@AlienScrOG, I don't think so. Challenge?
@deFharo, idroponica
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I disagree about a lot things on this article. I honestly don't think the plant cares how or where it gets its NPK as long as it gets it. It could care less if its from organic dry amendments or from some fancy set of 15 bottles with catchy names like super gigantic bud exploder. Not a scientist and have no desire to go down the rabbit hole but I've grown both ways and the differences are very negligible and I think come down to personal preference overall, but I do know one thing most organic growers are almost as bad as vegans and cross fit enthusiasts because I guarantee that you find out they grow organically in the first sentence that comes out of their mouths.
@Schwaggy,ho um amicone.. @xxanonymous... fissato con bio ... però ero quasi riuscito a farlo passare al lato bio dopo che gli ho fatto una talea
The writer is clearly a "soiler" 😘
J utilise du "bio" , organique donc et j ai toujours une carrence en fin de floraison, mes grandes feuilles jaunissent et mes têtes sont plus longues à mûrir. Je pense passer au synthétique pour compléter ma fin de flo. Des marques à me recommander ??? 🙏☮️
@Dolfom, adv ... atami bloombastic