best compost tea for cannabis

Organic Teas For Cannabis: How To Make And Use Compost Teas

Organic teas are used when growing organically and it’s a cheap and effective way to feed your cannabis plants without having to buy fertilizers.

Teas can be made with good compost, they contain nutrients and beneficial microorganisms that enhance plant growth and protect your plant against diseases.

1. What Is A Compost Tea?

A compost tea is what you get when you soak compost in water, the nutrients in the compost eventually end up in the water and the result is something similar to an organic liquid fertilizer but this fertilizer is full of microorganisms and nutrients that are beneficial for cannabis.

This happens because compost is full of beneficial microorganisms and nutrients, and when you soak it in water, you’re basically extracting them into the water, the goal being to enhance plant growth and protect it from diseases by providing those nutrients, beneficial bacteria and fungi to your plants, either through foliar feeding or through the soil

Organic compost teas are relatively new in the cannabis world but despite their lack of popularity, it’s a great way to enhance plant growth when growing organically, just have in mind that compost teas should never be a replacement for all the nutrients your plants need but can be a great complement when growing organically.

2. The Benefits Of Organic Teas

As said above, teas shouldn’t be used as an alternative to nutrients but they can be used to boost microorganism life in your organic soil and feed your plant when the soil is running out of nutrients, by doing this, you are feeding nutrients directly to your plant and taking care of the microorganisms present in the soil, which are the being responsible for breaking down and making the nutrients available for your plants.

Enhance growth

Compost teas boost microbial life in the soil and increase nutrient absorption, so it will not only enhance root growth but will keep your plants well-fed and keep your medium nutrient-rich.


Unlike synthetic fertilizers, compost teas are 100% organic because you’re only using natural sources so your tea is chemical and pesticide-free.

Improve soil

When done correctly, your compost tea should be well-aerated so when you use it to water the soil, it will aerate it and improve water retention, providing a healthier medium for the roots to grow in.

Protection against diseases

Beneficial microorganisms can boost your plant’s immune system and increase resistance against most diseases, also, these microorganisms can create a barrier that will help fight off harmful bacteria.

Cheap and effective

The majority of the materials needed for compost can be found easily and sometimes you might already have them at home, making this a really cheap and effective way to improve your organic grow.

3. Compost Tea Ingredients

Brewing your own compost teas can be quite confusing because of all of the options available, you can use whatever you want as long as you provide 3 basic elements:

  • Compost
  • Food and nutrients
  • Oxygen


The base of all compost teas is a good quality, healthy compost and should have a large microorganism population and lots of nutrients.

Having good compost can take a lot of time so if you are looking to make your teas and don’t have compost available, you can buy good quality compost at your local grow shop.

Food and nutrients

Food and nutrients are where you’ll be introducing the nutrients your plants need and the food for the microorganisms, you don’t need to add any extras if your compost is good enough but if you want to take your tea to the next level or you think your compost is not good enough, you can add any of the following ingredients, just have in mind that you can substitute any of them to what suits you better.

Molasses (non-sulfured)

Molasses serve as a food source for the microorganisms while you’re growing the tea.

Seaweed or kelp

Seaweed or kelp serves as a food source for fungi that grow while the tea is brewing, also serves to provide a surface for the fungi to attach to and develop.

Worm castings

Worm castings are the product obtained after a worm digests organic material. This product provides a lot of broken-down nutrients which are in a form that is readily available for your plant to consume and can also introduce microorganisms.

Bat guano or meals

Depending if you’re brewing teas for growing or blooming plants, you will have to provide a certain type of guano or meal, some guanos/meals are nitrogen-rich and others are rich in phosphorus and potassium, so you should choose carefully based on what you need to provide.

Both of these ingredients can boost your plant’s immune system and also feeds fungi, thus increasing its population.


Oxygen is vital when brewing organic teas because it allows microorganisms to thrive and can be tricky to get right because microorganisms need more oxygen than whats is available in water so you’ll have to get a good air pump and an air stone.

4. Simple Compost Tea Recipe For Weed

Here’s our recommended compost tea recipe, one for the vegetative stage and one for the flowering stage, a said above, you can use whatever you want as long as you provide what your plants need.

Just remember that teas are used to boost your soil, so you should be growing in amended organic soil or feeding your plants with organic nutrients because the teas are not a substitute for nutrients.

Also, make sure the water is at the right temperature (between 10-25°C) and that the water’s pH is between 6.0-7.0.

Diy compost tea

Here’s a table to help you make a good compost tea for your plants in the vegetative stage, the compost teas for plants growing and plants flowering is basically the same but you will have to change the minerals you’re introducing.

So, if you have a good compost available you won’t have to add anything else but if you don’t have it and can’t find it anywhere, you can use any type of nitrogen-rich guano or meal, this way you provide nitrogen which is the mineral cannabis plants need to grow.

Compost tea recipe for veg (20L)

Ingredients Quantity
Compost or guano or meal (high in nitrogen) 2 cups
Worm castings 1 cup
Powdered or liquid kelp/seaweed 1 tbsp
Molasses 120mg

Have in mind that this recipe was designed for when growing in organically amended soil, this is a basic recipe and you can improve it however you want to suit your plant’s needs.

There’s no specific brand or type of guano or meal you should use, as long as it has a high concentration of nitrogen and a lower concentration of phosphorus and potassium, it will work.

Compost tea recipe for bloom (20L)

Ingredients Quantity
Compost or guano or meal (high in phosphorus and potassium) 2 cups
Worm castings 1 cup
Powdered or liquid kelp/seaweed 1 tbsp
Molasses 120mg

As you can see, both tables are similar, the only thing that differs is the minerals you’ll introduce, as you may know, flowering cannabis needs more phosphorus and potassium so when brewing a tea for blooming plants, you need to introduce Phosphorus and Potassium-rich guano or meal.

Have in mind that although they’re quite similar, compost teas are usually called Compost extracts while if you’re using guano, molasses, and kelp (among others) is usually called Aerated compost teas.

Also, you can add mycorrhizae to your tea, this way you also provide beneficial fungi to the roots, improving root growth even more.

5. How To Make Organic Compost Teas Step-By-Step

Once you have everything you need, it’s super easy to brew teas, so here are 5 simple steps to guide you and keep your plants healthy and happy! You’ll need:

  • Bucket
  • Airstone
  • Air pump
  • Mesh bag

Step 1

First of all, in most cities the water contains chlorine and it can kill the microorganisms so depending on your water source, you should leave the water under direct sunlight or leave it oxygenating for 48hs before brewing your tea.

Step 2

Before brewing your tea, you need to figure out when you’ll be using it, teas take 24-36hs to brew, you don’t want to brew your tea for too long because as the microorganisms develop, they may run out of oxygen or space and will begin to die.

Only start the process if you will be using it within the next 36hs after brewing it, so for example, if you’re using it as a foliar spray, time your tea brewing so you can apply it when the lights are off or your plants are not getting direct sunlight.

Step 3

After dechlorinating the water, you need to check and adjust the pH which should be between 6.0-7.0 (it should be the same as your soil), and you need to calculate how much tea you’ll need, based on that you’ll know the size of the bucket you need.

Once you have your bucket, you need to have the air pump connected to the air stone, the air pump and the air stone will oxygenate the tea so the microorganisms can breathe.

Also, you’ll need a 400-micron mesh bag to place the ingredients in but it’s not necessary, you can substitute it with a clean pair of pantyhose.

Step 4

Now that you have everything ready, you can fill your bucket with water, then dilute the molasses straight into the water, place the ingredients in the mesh bag, put the airstones in the water, and start brewing.

Now, to know exactly how long it takes, you need to know the temperature of the water you’re using so here’s a table to help you.

Water temperature Brewing time
10°C 72 hs
15°C 48hs
20°C 24hs
25°C 24hs

Also, have in mind that you should remove the mesh bag after 23hs of brewing, so if your water is at 10°C, you should remove the mesh bag after the first 24hs and continue brewing for the remaining 48hs.

After you’ve finished brewing, your tea is ready to use so read along to know exactly how to use it.

6. How To Apply Compost Tea

So, organic teas can be used at full strength or diluted anywhere between a 1:20 ratio, this means the minimum amount you should use is 100ml per 2L of water.

You can apply the tea to the roots (by watering) or as a foliar spray, so depending on how you’re going to use it, you should dilute; Just have in mind that you don’t have to dilute it and organic teas won’t cause nutrient burn but by diluting it you avoid wasting precious tea.

There’s no such thing as a compost tea feeding schedule, but luckily, organic teas won’t overfeed your plants so you can use them anytime you think your plants are hungry or when you want to boost microbial life in the soil.

7. In Conclusion

Organic teas are one of the best ways to improve organically grown cannabis, they’re usually used as a boost when you see your soil is running out of nutrients or you just want to take care of your soil, this is a simple and effective method that should be tried by everyone growing organically.

If you have experience with compost teas and growing organically, please share your tips and tricks with fellow growers, leave a comment in the comment section below!

Why you should make and apply organic compost teas when growing cannabis organically.

The best compost tea recipe

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  1. Benefits of compost tea
  2. How long does it take to make compost tea?
  3. What is the best compost tea recipe?
  4. What you need to make compost tea
  5. Steps to making compost tea
  6. Can you burn your plants with compost tea?
  7. Bottom line on compost tea

If you’re a cannabis grower interested in the zero-waste movement , compost tea could be a good place to start. This is not the kind of tea that you pour into a mug and sip. Compost tea is an organic mix of active nutrients and microorganisms steeped in aerated water. The brew packs a nutritional powerhouse for soil, roots, and leaves, introducing healthy fungal colonies (think of how probiotics benefit the digestive system) and beneficial bacteria to cannabis plants. The results are a boost in plant growth and protection from disease.

Benefits of compost tea

Though not all growers agree on whether compost tea is any more effective than ordinary compost, some cultivators have pinpointed these potential benefits:

  • Reducing the presence of weeds and pests, which consequently helps cannabis plants fend off diseases such as blight. Compost tea may shield marijuana from pathogens that could harm or even kill the plant.
  • Infusing the cannabis plant with a strong dose of nutrients, which can potentially increase plant size due to a strengthened immune system from a diversity of trace minerals.
  • Eliminating the need for chemical fertilizers that ultimately harm the soil and the environment when contaminated water leads to runoff and seeps into public water supplies. With compost tea, you are creating something 100% organic, which facilitates a thriving and self-sustaining ecosystem.
  • Maximizing water retention in the soil, meaning less wasted water.
  • Improving the overall health of the plant with a beneficial cocktail of fungi, bacteria, protozoa, and nematodes of multiple species.

Some cultivators have pinpointed potential benefits of compost tea. Photo by: Gina Coleman/Weedmaps

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How long does it take to make compost tea?

Making compost tea is a fast process that lasts between 24 and 36 hours. A slightly longer brew will increase the amount of beneficial microbes, but you should not brew the tea for longer than three days. Doing so will cause the microbes to die out for lack of food supply. One benchmark to know if the brew is fresh and effective is that it will emit an earthy fragrance. Some gardeners claim that compost tea will stay fresh in the refrigerator for up to 30 days, but there is no reason to keep it on hand this long if you’re ready to apply the treatment.

Apply compost tea on sunny mornings when the plant stoma are most open to receiving and absorbing the mixture. A rule of thumb is to do it when dew conditions are favorable, so if you don’t have time to apply the tea early in the morning, do it at dusk.

How do you make compost tea to enhance your cannabis harvest? Here is an easy compost tea recipe, complete with all the necessary steps and ingredients.

What is the best compost tea recipe?

To whip up the best compost tea to strengthen your cannabis plants and make them more resilient, you’ll need five main ingredients:

  • Compost: The first and most important ingredient is compost with a rich biome of nutrients and microorganisms. The more developed the compost’s fungal colonies, the stronger the compost tea will be. Organic compost from local sources provides the best foundation for this recipe.
  • Kelp: This sea ingredient feeds the fungal colonies and aids in development, ultimately activating the potency of compost tea.
  • Molasses: More commonly used as an ingredient in baking, molasses feeds the helpful bacteria, encouraging them to proliferate and maximize the benefits of compost tea. For an extra infusion of potency, try blackstrap molasses, which is saltier and more bitter than the ordinary kind, making it better for brewing compost.
  • Worm Castings: Though not the most appetizing ingredient, worm castings are dense in easily absorbed nutrients and introduce a host of microorganisms to the tea.
  • Fish Hydrolysate: Like kelp, fish hydrolysate feeds fungi, but it also contains nitrogen and chitin, the latter of which serves as an immune booster to marijuana plants.

Once you’ve gathered these ingredients, you’ll need a few supplies before the tea brewing begins.

What you need to make compost tea

This simple compost tea recipe doesn’t require many supplies in addition to the main ingredients. You’ll just need:

  • Non-chlorinated water. It can be tap water that sits for 24 hours or, for a really organic experience, rainwater.
  • 5-gallon bucket, though larger gardens may need a larger size.
  • Watering can or spritzer.

In addition, if you would like to aerate the compost, which is recommended, you will need:

  • Air pump.
  • Aquarium bubbler.
  • 400-micron mesh bag or breathable fabric, such as pantyhose or any porous cloth.

The aquarium bubbler, kelp, and fish hydrolysate can all be purchased at a fish or aquarium supply store.

Steps to making compost tea

The three steps to making compost tea are straightforward:

  • Build the brewer: Place the aquarium bubbler in the bottom of the bucket and use plastic tubing to attach it to the air pump outside the bucket. Fill the bucket with non-chlorinated water.
  • Fill the teabag (aka the mesh bag): Remove any worms from the compost before you proceed with this step. Then, pour the tea ingredients into the mesh bag.
  • Brew the tea: Carve out at least a 24-hour period to let the pump run continuously and brew the tea. Be prepared to apply the compost tea to the soil as soon as possible, preferably within 36 hours of adding the bag to the brewer.

There is an optional fourth step. You can supplement the compost tea with items in addition to the kelp, molasses, and castings. Try a biologically active product such as Actinovate along with supplemental food for fungi and bacteria, if desired.

Once the compost tea has brewed, apply it to the soil. You can also spray some of the mixture onto the leaves for a more thorough treatment. This usage varies from plain compost, which is applied only to the soil and doesn’t directly reach every part of the plant . Foliar spraying is one benefit of compost tea, offering a more well-rounded treatment than might otherwise be possible.

Can you burn your plants with compost tea?

It is possible to burn plants with compost tea, especially if you are using a compost high in nitrogen. Manure-based composts tend to contain higher levels of nitrogen, so be sparing as you treat the soil if you are using this type and don’t spray it on the leaves. Otherwise, you can be more liberal in your treatment of the soil, especially since compost tea loses much of its potency within a few hours of brewing and long-term storage is not feasible.

Bottom line on compost tea

Compost tea is relatively easy and inexpensive to make. But it has a very short shelf-life and needs to be applied to the soil immediately to enrich the health of cannabis plants.

The best compost tea recipe Copy article link to clipboard. Link copied to clipboard. Contents Benefits of compost tea How long does it take to make compost tea? What is