Using Compost To Grow Cannabis Plants: Is It Worth It?

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Added 26 June 2023

In search of the best-growing methods for growing cannabis, we often take long strides and pick expensive, complex, or elaborate methods and mechanisms to get the best results. 

We often spend lots of money on fertilizers, soil supplements, and other products that can improve our plant’s growth.

But sometimes, simple things work best. 

And compost is one of them. 

It’s easy to make, easier to buy, and easiest to use — all while offering terrific benefits that set it apart from other methods. It is cheap (almost free), organic, eco-friendly, and effective. 

Learn all about composting for cannabis in this article below. 

What is Compost?

What is Compost?

Compost is a type of organic fertilizer that’s made from controlled decomposition of organic matter, like waste food products, plant material, grass, etc. Essentially, compost is made by allowing these organic materials to sit for a few months, allowing microorganisms to break them down into what we know as compost. 

Since compost comes from organic matter, it is eco-friendly and contains vital nutrients that are crucial for your plant’s growth and health. Plus, it can save you money since you won’t have to buy fertilizers. In the following sections, we will explore the benefits of compost, how to make it at home for cheap, and how to use it for cannabis plants. Of course, we will discuss compost tea too.  

Why Should You Use Compost for Growing Cannabis?

Why Should You Use Compost for Growing Cannabis?

Composting is one of the best ways of feeding nutrients to your cannabis plants since it offers various benefits that help not only your plant but also your wallet and the environment. Here are some of the best benefits of using compost for growing cannabis.

1. Cheap yet Effective 

Using compost for cannabis is incredibly cheap, and if you use the right method, it can even be completely free. At the same time, it does not compromise efficiency while saving you money; it is one of the most effective fertilizers you can use on your cannabis plant. Essentially, compost creates a healthy environment in the soil that benefits the plant much better than simply adding nutrients from the top. 

2. Creates a Healthy Environment for the Plant

Compost encourages microorganisms in the soil that can help turn regular soil into rich, healthy soil. And this can offer various benefits that improve your plant’s health and boost its growth, eventually leading to a better, higher-quality yield. For example, it encourages the growth of predatory nematodes that defend your plant from parasitic nematodes, and it also boosts mycorrhiza in the soil, which improves nutrient uptake

3. Does Not Burn the Plants

Compost is also a slow-release fertilizer, so it won’t ever overwhelm your cannabis plants with nutrients, which can cause nutrient toxicity or burns on the plant like other chemical fertilizers. Instead, compost takes a three-pronged approach to feeding your plants — it improves the aeration and texture of the soil while releasing nutrients slowly over the months. 

4. A Closed Loop System for You 

You can use many items you’d typically consider as waste at home. Yes, those tomatoes or leafy greens you throw away as wet waste? Those are perfect for composting. Over time, this can help you create a closed-loop system where you can turn waste into food for your plant and once the plant is harvested, the waste material can be added back to the compost. Soon enough, you won’t have to purchase anything, and it will reduce the waste your house produces. 

5. Other Benefits

Composting for cannabis also offers other benefits, such as the following:

  • It improves your grow medium’s ability to retain moisture 
  • Creates a healthy substrate for the roots to thrive in 
  • Introduces beneficial bacteria and other microorganisms in the soil 
  • Acts as a source of food for various worms, improving the overall soil food web 
  • Combats diseases and controls the growth of weeds around your plant 
  • Lowers your cannabis operation's carbon footprint

Can You Buy Compost for Cannabis?

Can You Buy Compost for Cannabis?

Of course, the easiest way to use compost for cannabis is to purchase it from your local gardening or farming store. Bagged or commercial compost is relatively cheap unless you have a massive garden and is a viable option if you don’t want to invest months in creating compost at home for cannabis. 

Visit your local gardening store, and you will have various options. Each product will have its pros and cons, so be sure to weigh your options and pick the one that suits your preferences, budget, and conditions best. It’s also better to read reviews online or rely on first-hand experiences from your fellow growers. 

Also, regardless of the brand you choose, ensure it’s made of 100% organic materials. Otherwise, your plant may not get to enjoy all the benefits of compost as you’d expect. And ensure they are pesticide-free, too. 

Ideally, it is recommended that you smell the product before paying the bill; avoid compost that smells like ammonia (not mature); your compost should be fluffy and dark. 

Can You Make Compost at Home for Cannabis?

Can You Make Compost at Home for Cannabis?

Purchasing compost from a store is easy, but if you want the best results, it is often better to make your compost at home for cannabis. But unlike other supplements or fertilizers, compost is super easy to make. You only have to create the right environment. The rest of the work is done by microorganisms. 

Follow these steps to make compost at home for cannabis.

1. Prepare a Compost Bin

The first part of making compost at home is preparing a compost bin that will act as a container for the composting materials. You can either buy this from a store or build it out of scrap at home. Ideally, choose a bin with a lid since it can improve moisture retention so the materials can break down faster. 

Here are some of the common types of compost bins you can try:

  • Plastic Compost Bin

The most basic and common type of compost bin is the plastic composter, which is easy to maintain and own since it is compact and long-lasting. The downside is that it’s plastic, so it’s not the most eco-friendly option.

  • Commercial Composter

Often made of plastic, a commercial composter is similar to the plastic compost bin, but it is designed for large gardens or farms. They feature top access for adding waste materials and a door at the bottom to collect the mature compost. The most significant advantage of a commercial composter is that it prevents rodents from making their way into the bin and is the easiest to work with, but they can come at a cost. 

  • Drum or Barrel Compost Bin

A drum or a barrel compost bin is DIY; simply get a barrel or a drum and use it as your compost bin. Easy peasy lemon squeezy — isn’t it? But make sure you make some holes in the drum to start composting, and if you want, you can also make a door at the bottom to access mature compost.

  • Wooden or Brick Composter

If you want a DIY bin but more elaborate than a drum, you can use wood or bricks to create compost in your backyard. It is recommended that you build it with a top door and design it in such a way that you can disassemble it for maintenance. 

The size of a brick or wooden composter will depend on your requirements, but you can start with a meter cube — this will have enough space for a lot of waste. 

  • Mesh Composter

Lastly, you can also make a mesh composter with wire mesh. Join the ends to stakes or poles and secure the structure to the ground. The benefit of a mesh composter is ventilation, but you will have to keep an eye on temperature and humidity since the organic matter can dry out before it is composted. 

2. Pick the Right Spot

Next, you need to place your composter in an area with shade. This is crucial so that the microorganisms can do their work to break down the compost. Also, if possible, place your compost on top of the soil for drainage, helping the worms access the compost easily. Ideally, the compost must also be protected from strong winds, fluctuating conditions, and storms. 

Protip: Add a Second Bin

When placing the main compost pile outdoors, you should also place a smaller compost bin in your kitchen. You can use this bin to collect food scraps and other waste materials from your kitchen and transfer the heap into your main compost every few days. This will save you multiple trips to your garden every time you eat a banana or make tea. 

3. Add Suitable Organic Matter to the Compost

The next step is to add organic materials to the compost but don’t add whatever wet waste you can get your hands on. You need to be considerate and strike the right balance with what you add to the compost. Doing so will ensure the microorganisms have ideal conditions to break down the materials. 

There are two main types of materials you need to add to your compost: green material and brown material. Let’s take a look at each below. 

Green material, as the name suggests, is any kind of material that contains high levels of nitrogen. This material acts as food for bacteria and fungi that help make the compost, and it also supplies moisture to the compost pile. Green material includes the following:

  • Green leaves
  • Grass 
  • Fruits and vegetables
  • Animal manure
  • Uncooked kitchen waste like banana peels, egg shells, vegetable skins, tea bags, etc. 
  • Seaweed 
  • Soft, leafy plants 

On the other hand, brown material consists largely of carbon, which acts as a carbon source for the compost while also soaking up excess moisture. Common brown materials for compost include the following:

  • Dead leaves
  • Egg cartons
  • Cardboard 
  • Twigs and sticks, straws, branches, etc. 
  • Wood chips or sawdust 
  • Paper 

You need to strike the right balance between the two types of materials. Too much of either can cause problems like your compost becoming too slimy, dry, or inefficient. Ideally, add 25% to 50% green materials and 50% to 75% brown materials, depending on your preference, for the best results. 

4. Avoid These Materials

As mentioned earlier, you should not add certain things to your compost as they are not compatible with the pile and can cause problems in the future. Such products include meat, pernicious weeds, dairy products, and dog and cat waste.

5. Maintain the Compost Pile

The last tip for making cannabis compost at home is to maintain the heap for a few months. This doesn’t require much effort, so it can be left on its own for the most part. Let the microorganisms take care of it. However, remember to check it occasionally to ensure it hasn’t become too wet, dry, or slimy and doesn’t smell weird. More on this later. 

You should also use a pitchfork to turn your pile every couple of weeks to increase aeration. Depending on your local conditions and the materials you use, your compost should be ready in 6 months, but sometimes it can take as long as 2 years. 

What Type of Compost is Best for Cannabis?

What Type of Compost is Best for Cannabis?

Whether you use compost or other nutrients, it’s essential to use ingredients that balance it and provides the best nutrition to the plants. There are numerous kinds of composts that serve cannabis well. 

Here are a few you could look into:

1. Organic compost

Typically, you can make organic compost from a combination of plant waste such as fallen leaves, turf trimmings, veggie scraps, and other sources like sawdust, straw, and wood chips, This composting procedure breaks down the raw material right into nutrient-rich humus. Organic compost improves the soil structure and also retains water while providing a vast array of necessary nutrients for marijuana plants. Also, it increases the microbial population in the soil, which makes the plants robust. 

2. Worm castings

Worm castings are the waste matter produced by earthworms. They are an extremely in-demand garden compost for marijuana farming because of their amazing nutrient content and microbial variety. Worm castings consist of high amounts of beneficial fungi and bacteria and enzymes to aid healthy plants. They are abundant in essential nutrients, such as nitrogen, phosphorus, potassium, calcium, magnesium, and many trace elements. Worm castings also assist the plants in absorbing nutrition and boost general plant health. 

3. Bat guano

Bat guano is nothing but bat droppings or manure, usually found in caves. It is a powerful natural plant food thanks to its high nutrient content. Growers love bat guano as it’s rich in nitrogen and phosphorus that help the plants develop robust stems and leaves and in bud development. Since there are various types of bat guano available, and they all differ in the type of nutrition they offer, you should use it according to your plant’s stage of growth. 

4. Composted Chicken Manure

Chicken manure is an abundant resource of nitrogen, phosphorus, plus potassium. But always make sure the manure is composted well, as fresh manure can cause more harm than good. Also, you must use small quantities of chicken manure as it’s too strong and can burn your little plants. 

One way to use chicken manure safely is to compost it, as the material breaks down organically and becomes safer and balanced. Well-composted chicken manure not just offers important macronutrients but also increases the microbial population. The plants get a solid nitrogen boost, so you can use it mostly during the vegetative stage for best results. 

5. Fish emulsion

Fish emulsion is in liquid form and is available in most plant nurseries. It is produced once the enzymes in the waste break down systematically. It is usually made from a mix of entire or some parts of fish. It contains high amounts of nitrogen, phosphorus, and many elements. Although using it doing the flowering stage won’t necessarily hurt your cannabis plants, it’s especially effective in the vegetative phase. 

You can use fish emulsion either as a foliar spray or pour it on the soil after diluting it according to the manufacturer’s instructions. The plants tend to absorb nutrients offered by the emulsion very quickly, which is very useful if you want immediate results. 

Regardless of the type of compost you use, make sure you either make it at home or purchase from companies that only sell high-quality products. This is because there are scores of companies that just sell dirt as compost. The compost you use should be free of pollutants and other harmful bacteria that can be detrimental to the plants. 

What is Compost Tea?

What is Compost Tea?

Compost tea is a liquid fertilizer that is derived from steeping compost in water. It is a method where you extract the beneficial microorganisms, nutrients, and other compounds from compost and make them available in a liquid form. This is done so the plants can easily and quickly absorb the nutrients. Compost tea acts as a natural plant tonic and soil conditioner.

To make compost tea, you begin with top-notch garden compost like worm castings or well-aged garden compost. Typically, you place it in a container or mesh bag and add water. You can also include extra active ingredients like molasses or kelp meal to improve the microbial population and nutrient content. 

Then, you allow the blend to brew for about 24-48 hours, allowing the beneficial microorganisms present in the compost to multiply and proliferate in the water. This will create a diverse and active microbial population.

Once the brewing period ends, you can strain and remove any solid particles or residue. You will end up with a liquid fertilizer that many growers call “liquid gold,” especially if you’ve used worm castings in the process. 

You can use compost tea through foliar spraying or drenching the soil around the plant's roots. If you use it as a foliar spray, the plants will absorb the microorganisms and nutrients in the tea directly through the leaves, boosting plant health and resilience. If you drench the soil with it, it will improve the structure of the soil, enhances nutrient availability, and promotes beneficial microbial activity in the root zone.

The benefits of compost tea include:

Increased nutrient availability: Compost tea contains a range of nutrients in a readily available form, making them more accessible to plants.

Enhanced soil fertility: The beneficial microorganisms in compost tea help break down organic matter, release nutrients, and improve soil health.

Improved plant growth and vigor: The application of compost tea can promote root development, enhance nutrient uptake, and stimulate plant growth.

Disease suppression: Some beneficial microorganisms present in compost tea can help suppress harmful pathogens, protecting plants from diseases.

Note that you should use compost tea within a short period after brewing to ensure the viability and effectiveness of the beneficial microorganisms. In addition, you should use proper brewing techniques that include aerating the mixture and maintaining appropriate temperature and brewing times to maximize the quality and effectiveness of compost tea.

Can you use compost tea to grow cannabis?

Can you use compost tea to grow cannabis?

Yes, compost tea can be used as a beneficial supplement for growing cannabis. Cannabis plants can greatly benefit from the application of compost tea due to its nutrient content and the presence of beneficial microorganisms. Here are some ways compost tea can be used in cannabis cultivation:

Nutrient supplementation: Compost tea contains a range of nutrients that can help meet the nutritional needs of cannabis plants. These nutrients, such as nitrogen, phosphorus, potassium, and trace minerals, are released from the compost during the brewing process. Applying compost tea as a soil drench or foliar spray can provide an organic and readily available source of nutrients to support healthy growth and development.

Microbial inoculation: Compost tea is rich in beneficial microorganisms, including bacteria and fungi, that are crucial in enhancing soil health, absorbing nutrients, and plant vitality. When you apply compost tea to the soil, it introduces a diverse microbial population that can colonize the root zone and improves nutrient uptake by cannabis plants. The presence of beneficial microbes can also help suppress diseases and pests. Foliar applications of compost tea are particularly useful if you notice any stress or nutrient deficiencies, as they provide a quick and effective way to deliver nutrients.

Soil conditioning: Compost tea can help improve soil structure and fertility. The organic matter and humic substances present in compost tea can enhance water retention. Regular applications of compost tea can contribute to developing a healthy and thriving soil ecosystem, which is essential for optimal cannabis growth.

How to Fix Problems with Compost for Cannabis?

How to Fix Problems with Compost for Cannabis?

While making your own compost, one of the things you must remember is that you don’t control the process; nature does. As a result, the compost may run into some problems occasionally, but these problems will likely not ruin the compost. Follow these techniques to fix the most common compost problems easily.

1. Wet or Slimy Compost

Depending on your region and the local environment, different microorganisms will thrive in your compost pile. Ideally, your compost pile should contain aerobic microbes that decompose organic matter when they receive oxygen. Essentially, these organisms generate heat that breaks down organic waste. 

To ensure these organisms get enough oxygen, the compost pile shouldn’t be drenched in water. To reduce water content, add a healthy amount of brown material that can soak up excess moisture and create air pockets. 

Similarly, if your ratios are off and you add too much green material, your pile can get drenched and become wet or slimy. This is not only an aesthetic problem but can also keep the microorganisms from breaking down organic matter efficiently. When that happens, your compost will turn slimy over time and not black. 

As you can guess, fixing this problem is easy. All you have to do is add brown materials to your compost and let them absorb excess moisture. You should also use a pitchfork to turn the pile once every week to introduce more air pockets. Give it a couple of weeks, and your compost will be healthy again. 

2. Dry or Fibrous Pile

The opposite of a slimy compost can also be a problem; here, your compost can turn too dry due to a lack of enough water, nitrogen, and nutrients. This prevents the microorganisms and worms from thriving, and the fewer the worms, the slower the breakdown process. 

An easy way to fix this problem is by simply adding more green materials to your compost pile. You can also use compost accelerators. If your compost pile sits on gravel or concrete, you can introduce worms to the pile to hasten the composting process

3. Odor From the Compost

The third most common problem you may run into with your compost pile is a bad odor, i.e., when your compost starts smelling considerably worse than normal. This can occur if your compost pile is rich in nitrogen or if it is too moist. 

Fortunately, the solution to this problem is the same as slimy compost. Add more carbon-rich brown material to your compost pile to remove excess moisture and bring balance to the nitrogen levels within. Aerating it also helps.

4. Flies and Insects 

If you find flies and insects all over your compost, don’t be alarmed. While this may seem like a problem, it is completely normal for your compost to attract flies and insects. In fact, some of these insects can even aid your compost significantly, just like worms!

If you still find it bothersome or if the insects are getting into places they shouldn’t in your garden, you can place brown material (like cardboard) over the pile to prevent them from getting to the compost. If that doesn’t fix the problem, consider adding a lid to your compost if you haven’t already.

How to Use Compost to Grow Cannabis?

How to Use Compost to Grow Cannabis?

You’ve made it this far: weeks of patience and light maintenance, your kitchen looks clean, the waste bin has been relatively happy, the garbage collector has been happy with you, and the worms have outdone themselves in your compost pile. So, what’s the next step?

Using your homemade compost on your cannabis plants! 

Remember, your compost is unlike other fertilizers. Think of it as a soil amendment and not a fertilizer in the true sense; it enriches the medium while creating a healthy environment within the substrate for the roots to thrive. It creates rich soil. On the other hand, fertilizers feed plants directly and may overwhelm the roots with nutes. 

So, it’s super easy to use compost on your cannabis plants. For an outdoor plant, you simply have to top off the soil with compost. Here, the amount depends on your soil, its quality, and nutrient richness. Ideally, consider adding compost to your soil in the fall, and it will last all the way up till spring. You may have to occasionally add compost to the soil, if necessary, to give your soil a boost and minimize your reliance on fertilizers. 

For an indoor plant, the same rules apply, but be a little conservative with how much fertilizers you add to the soil. Also, your plant will likely grow with more vigor, so prepare for it. 

Make Cannabis Compost 

The entire article talks about compost for cannabis, but as a bonus, here’s some information on cannabis compost, aka compost with cannabis in it. It’s nothing but using leftover cannabis materials as green materials for your regular compost pile. 

Like most other green materials, cannabis matter can be a terrific addition to your compost. For example, cannabis leaves have a carbon-to-nitrogen ratio of 15:1, but the stem has a carbon-to-nitrogen ratio of 30:1. While it’s mostly green, it also features a lot of fibrous brown that can help the compost.

Some of the best components of your cannabis plant waste that can be added to the compost include fan and sugar leaves, waste flowers, stems and branches, and leftover cannabis products like ground-up flowers. 

Here’s a pro tip: consider grinding your cannabis waste matter before adding it to the compost pile. This will help the material spread evenly within the compost. Plus, a passerby won’t easily notice the cannabis leaves if you want to keep your operation private. 

Summary: Using Compost to Grow Cannabis Plants: Is It Worth It?

Isn’t using and making compost super easy? Compost is a traditional gardening method that has been used for centuries, and it’s no surprise it has stood the test of time — it is effective. There’s a reason why composting was taught to many of us in schools! 

Compost is nothing but broken-down organic matter, which includes green materials that break down into compost and brown materials that control moisture and act as food for microorganisms. And since composting is a process mostly handled by nature, it is easy to accomplish with little patience and a lot of waste. 

So, prepare a composting bin, place it in a shaded spot, add organic material, and keep an eye on it. If it turns wet, slimy, or smells weird, add more brown materials, and if it feels dry, add more green material. That’s about it. 

And when it’s time to use it after at least six months, simply top your soil with it and let it do its magic on your plant’s growth and health. You will be surprised at how this easy method can improve your plant’s yield and flavor.



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Can I just take a bottle of my sister´s dirty fishtank and use it to water the plant? Newbie here
@Domingocito, Ich hatte Probleme mit Trauermücken, die Larven haben den Wurzeln bei mir aber nicht geschadet 👍🏼 du kannst aber nützliche kaufen die die Larven fressen, ohne deine Pflanze und deine Erde damit zu versäuchen. Musst mal schauen welche bei dir helfen, bei mir waren es nermatoden
@Organic_G, I ´m having problems with several kinda maggots in the soil, I water the plant with pesticides, should I leave them alive then? Cause they will probably eat the roots and leave extrement behind, not healthy I guess...? Grtz
@Domingocito, Das war Spaß, ich bin sehr vorsichtig was alles bei mir rein kommt, nutze selbst Osmose Wasser, nur organische Dünger etc. Baue mir momentan sogar mein Living Soil mit Würmern etc. Daher auf keinen Fall versuchen 😂 alles was rein kommt kommt auch als Früchte wieder raus ;)
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i cant imagine growing my babies without compost. lovely artricle