How to Make Homemade Fermented Plant Juice (FPJ) — A Complete Guide

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Added 12 September 2022

If you are growing cannabis, you cannot completely rely on fertilizers. 

Branded ferts are expensive, especially if you are growing cannabis in a large quantity. 

Apart from that, many other chemical fertilizers are not sustainable for your plant as well as the environment.

But there is one alternative, among many others, that may surprise you with its benefits — homemade fermented plant juice (FPJ) for cannabis. This juice has the potential to improve your plant’s growth and even yield bigger buds.

What is homemade FPJ and how you can make it at home? Read on to find out how to make fermented plant juice for cannabis plants.

What is Fermented Plant Juice?

FPJ for cannabis

Before we get into what fermented plant juice is and how to make DIY FPJ, let’s understand its context and history.

History of Fermented Plant Juice

Back in the day, Master Han Kyu Cho of the Janong National Farming Institute in South Korea developed a sustainable farming system called the Korean Natural Farming (KNF). This system was based on the previous generation’s farming practices, particularly in Korea, Japan, and China. 

This system was developed to optimize the production of plants (and livestock) that maintains a balance between the nutrient input and output while minimizing any harmful effects on the environment. This is done by encouraging IMO or indigenous microorganisms that occur naturally and produce the nutrients for the plants.

Plus, another feature of this system is that all the inputs are readily available everywhere locally at a drastically cheaper rate than fertilizers, composts, and feeds.

Fermented plant juice is one of the preparations for the KNF growing system. 

Homemade Fermented Plant Juice

Fermented plant juice is nothing but the fermented extract of a plant’s chlorophyll and sap. This juice is rich in enzymes and full of microorganisms like yeast and lactic acid bacteria, which encourage vigorous plant growth when applied. 

Essentially, homemade FPJ for cannabis consists of young shoots taken from other vigorously growing plants, which are then fermented for around a week with the help of brown sugar. The brown sugar extracts the juice out of the plant parts with osmosis while serving as food for microorganisms that carry out the fermentation process.

During the extraction process, weak alcohol is produced which extracts chlorophyll and other plant components. And, the best part? This juice is non-toxic and completely edible. Plus, making organic fertilizers for cannabis is a fun hobby. 

Benefits of Homemade Fermented Plant Juice for Cannabis 

Fermented plant juice for cannabis is primarily used as nutrition for the plant, but it can also be used for seeds or treatment of soil. Here are a few benefits of this juice for cannabis:

1. Improves cannabis’ resistance to extreme weather changes

Some cannabis strains are not so resilient to extreme weather changes, especially to frost. However, by making fermented plant juice from plants that are resilient against harsh conditions, the same benefits can be passed onto the cannabis plant, improving their endurance.

2. Enhances the Plant’s Recovery Process

If your cannabis plant is recovering from a health condition or growing weak, you can make fermented plant juice with plants that grow fast and vigorous as they have active growth hormones.

With the help of FPJ for cannabis, you can pass on these hormones to your plant and help it recover quickly.

3. Improves Cannabis Growth

Similarly, FPJ made from vigorous plants like bamboo shoots can also help your cannabis plant grow more vigorously.

4. Thickens Foliage and Buds

FPJ juice can also help boost your plant’s foliage and bud production. Here, FPJ needs to be prepared from thinned-out fruits that are rich in gibberellins, which make the cannabis plant healthy and enhances bud production.

How to Make Homemade Fermented Plant Juice for Cannabis

The Korean Natural Farming (KNF) system of cultivation was developed specifically for being easy and accessible for every farmer (or grower). Thus, with the help of a few basic supplies and plants in your vicinity, you can easily make homemade fermented plant juice for your cannabis plants.

The process of making homemade fermented plant juice begins by knowing and planning the process, followed by picking the right plants and preparing the mixture. Here is a short guide on how you can make FPJ juice at home for cannabis.

Factors that Affect the Quality of FPJ for Cannabis

There are a few factors that you need to consider even before you start picking the plants to prepare your homemade fermented plant juice, such as the following:

  1. Perhaps the most crucial requirement is to choose plants that are already fast and vigorous growers at the time of collection.
  2. You should always harvest the plant material when the plants are in respiration mode, i.e., before sunrise, and not during the photosynthetic mode during the day. This is because photosynthesis affects plant chemistry, which is not suitable for making a good FPJ juice for cannabis.
  3. Additionally, you should also avoid picking plant parts during or after rainfall as the water can wash away the microbial populations on the parts that are responsible for the fermentation. Instead, wait for at least two sunny days post rainfall.
  4. For the same reason, you should also never rinse the plant parts. You can still clean them with your hand to remove any dirt or grime, but avoid washing them. 
  5. You can also use flower buds, flowers, and immature fruits, but avoid using hard or woody parts of the plant since they yield very little plant juice, which is not good for the final juice.

Follow these tips and you are on your way to making a strong homemade fermented plant juice for your cannabis plants.

Best Plants for Homemade FPJ 

As mentioned earlier, you can choose any plant for making FPJ for cannabis as long as it is a fast and vigorous grower (and healthy). Generally, the most common plants used for preparing FPJ are mugwort, dropwort, purslane, watercress, bamboo shoots, angelica, and sweet potato vines.

If you can’t find some of these plants in your vicinity, you can also use other common options like beans, seaweed, pumpkin, immature fruits of noni, and squash shoots. 

Also, Korean Natural Farming is a system built around what is readily available, so there is no need to order plant parts from another state or location. You can go beyond and choose other plants. The options are endless. Ensure the plant is healthy, non-poisonous, and fast-growing, and you can make a potent FPJ out of it. 

Step-by-Step Guide to Making FPJ at Home for Cannabis

Fermented plant juice can be made at home any time of the year, but if you live in a temperate region, you should choose the summer months for picking the plants. This is because, during the warmer months, the plants grow vigorously and tips are abundant all around.

Follow these steps to make your FPJ for cannabis:

1. Collect the Plant Material

Collect plant material

It’s time to start preparing. So, get a sharp pair of scissors and collect plant materials before sunrise. You need to cut off the fast-growing tips at a length of 2 to 3 inches. And if the plant has longer tendrils, like sweet potato, then you can also collect longer pieces.

Remember, never collect plant material during the day or after rainfall. Wait for a couple of days of sunlight before collecting the plant materials.

2. Cut the Plant Material

Cut plant material

Do not rinse your plant material yet. If they appear dirty, you can clean them by hand but do not get them wet. Then, cut the shoot tips into 2 to 3 pieces and weigh them after cutting.

3. Add Brown Sugar

Add brown sugar

The next step is to weigh out your brown sugar. Here, the weight of the sugar must be the same as that of the plant material.

Then, toss the plant materials and brown sugar in a large bowl and stir them. The goal of stirring is to cover the entire surface area of the plant material in brown sugar to expedite the osmosis process. 

4. Pack the Mixture

Pack the mixture

Once the plant material is coated with your brown sugar, toss the mixture into a container. Ideally, you should choose a container that is either a clear glass or food-grade polyethylene (PE) container. You don’t need a lid at this stage. 

Also, avoid using metal because it can react with the solution.

Now, once the container is packed to the brim, cover it with a heavy cheesecloth, muslin, or towel to allow air exchange. And use a string to hold the cloth in place and deter pests. 

And store the container in a well-ventilated but dark place, away from natural or artificial light and extreme cold or heat.

5. Check After a Day

Check after a day

After 24 hours, check the container. The volume of the plant material should have settled to ⅔ of the container. This compaction is necessary for the fermentation to occur properly, otherwise, the microbes will not have enough air to ferment the plant materials.

If the plant materials have not settled, you can remove some of them until the container is ⅔ full. But if the plant material has settled more than expected, you can add a little more — this would prevent mold infestation.

Also, some plants may not settle in 24 hours and may require a longer time. In that case, check again in the next 24 hours.

6. Let the Mixture Ferment

Let the mixture ferment

The fermentation process depends on the ambient temperature, so if you live in a warmer or humid region, the fermentation should take 3 to 5 days to complete. In colder regions, the same occurs in 7 to 8 days. 

Keep checking the jar daily. You will notice bubbles in the container when the mixture is fermenting. And you will know the fermentation is completed when:

  • The liquid settles at the bottom and the plant material floats, but this separation may not be distinct if you have used too much brown sugar
  • The container smells of light alcohol because the chlorophyll from the plant material has broken down
  • Taste it — it should taste sweet, not bitter

7. Separate the Liquid 

Separate the liquid

Once the fermentation is complete, use a strainer to separate the liquid from the solid material. The liquid is your homemade fermented plant juice for cannabis, and you can either use it immediately or store it in a loosely covered container.

And don't throw away the remaining solids just yet. You can spread them around in your compost or use them as animal feed as they still contain a lot of healthy nutrients for plants and animals. 

8. Store FPJ 

Store the FPJ

Now that your FPJ is ready, you need to store it properly. Otherwise, it can become ineffective real quick. So, transfer the liquid into a food-grade PE container or a glass jar.

Remember, the microbes in the liquid are still alive and kicking, and they will continue to produce gases. So, keep the lid loose unless you want your container to explode. 

Also, when you make your next batch of FPJ juice, store it separately. Storing two different batches together is not recommended unless you will be using them immediately.

If you want to store your FPJ juice for the long haul, you need to add an equal amount of brown sugar, again, to the liquid. This will prevent the juice from going sour.

How to Use FPJ on Cannabis?

Fermented plant juice can be applied to your cannabis plant after diluting it with water. You can either use it as a foliar spray or soil drench. 

But, when do you use your homemade FPJ? Well, that depends on the plant material you used for fermentation. So, when you make your FPJ, consider when you want to administer the juice to your plant. 

For example, juice made from bamboo shoots or mugwort can be applied to cannabis from germination to the early vegetative stage. And arrowroot or bamboo shoots can be applied to vegetative plants that need nitrogen.

If you want to administer it to an early flowering cannabis plant, you can use green, unripe fruits from source plants since they are rich in phosphorous — they encourage flower shoot development.

Similarly, for plants that are nearing maturity, you can use plants that are rich in calcium to make the FPJ and store it for a year before administering it.

Here are a few instances where you should never use fermented plant juice:

  • If your plant is in an excessive vegetative growth caused by rains since this can cause a nutrient burn 
  • Never use FPJ that is made with the same crop, i.e., don’t use cannabis FPJ on cannabis 
  • If your garden’s growth conditions are acidic or rich in nitrogen, avoid FPJ as it can invite pests to your garden
  • Lastly, if the growth conditions are too moist or lack good ventilation, avoid FPJ as it can encourage fungal growth

Preparing and Applying Homemade FPJ to Cannabis

As mentioned above, you need to first dilute FPJ with water. Here, if you have old juice stored, you should mix both old and new in the solution. Generally, you need to add 1 part FPJ to 500 parts water (ratio of 1:500).

But if the growth conditions are already rich, you can use a ratio of 1:800 or 1:800 to avoid leaf burn. Diluted ratios are recommended if you are using more than three plant ingredients, applying during the summer months, or if the juice is more than a year old and becomes concentrated.

The best time to apply FPJ to your cannabis plant is during the late afternoons, an hour before sunset, once every week. You can either apply it as a foliar spray directly onto the canopy or water into the soil or growing medium. 

What are Some Other Tips for Making and Using Homemade FPJ for Cannabis?

The above sections cover all you need to know, but to help you better, here are a few tips on preparing and using homemade fermented plant juice:

  1. Avoid using molasses when making FPJ as it contains too much moisture, which can raise the osmotic pressure and prevent brown sugar from extracting the plant goodies
  2. You may also notice some small bubbles or fungi in the container during fermentation, which is a result of low brown sugar quantities; in this case, add more brown sugar and stir the mixture
  3. Avoid keeping the fermenting container in direct light or heat 
  4. Avoid picking plant material when it's rainy as it washes away lactic acid bacteria and yeast, which are essential for the fermentation process. If it rains, wait at least two days before picking them
  5. Lastly, avoid picking material from plants that are near the road as they may be polluted 

Is FPJ the Same as FFJ? 

While fermented plant juice and fermented fruit juice are part of the Korean Natural Farming system, they are quite different. FFJ is prepared from fruits specifically as artificial honey, which makes it rich in nutritional activation enzymes.

The common fruits used for preparing FFJ include banana, papaya, mango, apple, and melons — sweet fruits, not citrus fruits. 

If you want to make fermented fruit juice at home, follow these steps:

  1. Prepare at least three fully ripened fruits. If you can’t find enough fruits, you can use supplements like spinach roots, cucumber, cabbage, or radish.
  2. Then, for one kg of fruits, use 1.2 kg of brown sugar in hot weather and 1 kg of the same in cold weather.
  3. Spread sugar on the chopping board and cover the fruit in it before placing the mixture in a container.
  4. Stir the mixture a few times with wooden sticks. Make sure you stir a bit more during cold weather.

NOTE: You can also use half of the weighed sugar to douse the fruit materials and sprinkle the remaining half over the mixture in the container, whichever is easier for you. 

  1. Then, cover the container with porous paper and tie using rubber bands or thread.
  2. Let the mixture ferment for 4 to 5 days in hot weather and 7 to 8 days in winter.
  3. Once it has fermented, strain the liquid out and sprinkle some more sugar for storage.

If you want to use FFJ during the changeover period, you need to make FFJ with less ripe fruits like papaya, mulberry, grape, and raspberry, since they are rich in phosphoric acid. And during the bloom stage, you should use fruits like banana, apple, mango, peach, and grapes that are rich in calcium

Don’t forget to dilute FFJ with a 1:1000 ratio in water before administering it to your cannabis plant. 

That’s the only difference between FPJ and FFJ — otherwise, they are quite similar in their benefits and effects. Ideally, we recommend using FPJ over FFJ as it has a more flexible use case for the cannabis plant.

Summary: How to Make Homemade Fermented Plant Juice (FPJ) — A Complete Guide

Fermented fruit juice is a terrific substitute for chemical fertilizers, and it is completely organic, sustainable, and eco-friendly. Plus, you can make it for almost free — all you need is some brown sugar, a glass jar, and access to a few plants in your vicinity. 

It won’t take you more than an hour to collect the plant materials, and once you have those ready, an afternoon is all you need to prepare the mixture for fermentation. Then, keep checking it daily for a week — it should be fermented and ready for use in 5 to 7 days. 

Once it is ready, you can either use it as a foliar spray or add it to the soil. And if you want to store it, use the right technique mentioned above to store it for the long term. With the right measures, you can store your homemade fermented plant juice for a year. 

And FPJ for cannabis is a good starting point, but if you want to learn more about Korean Natural Farming stay tuned as we are going to post a lot more about it. 



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something I would be interested in trying. Wonder if it would work with any of the local weeds I have like golden rod.
@m0use, yes it works with most plants like medgrow said. So, far I have tried mint, comfrey, and spinach. For flowering, use fruits.
@m0use, It works with any herb, plant, or fruit as long as you use it properly.
Hey, it's fermented plant juice, not fruit plant juice and it takes much longer than 7 days to be ready.
@Medgrow93, sorry it was a typo. Corrected it
Question when growing cannabis KNF MEthod It recommended to use Fpj for veg and FFJ for flower ?