Compost tea is traditional compost steeped in water, to create an extract for use as a soil drench or foliar feed. Farmers have used compost tea for generations as a cheap and effective means of adding nutrients to plants; however, the cannabis community only woke up to compost tea’s potential within the last decade or so.
Now, countless products are commercially available, so that you can mix your own compost tea in minutes from a packet if desired. However, making your own compost tea is a fun and rewarding way to learn more about organic plant nutrients, and in the long run will prove much cheaper than buying in expensive pre-mixed products.
But why should I make compost tea for my cannabis plants?
Pretty much every grower of any plant will be aware that adding compost to soil can enrich it greatly. Growers of organic cannabis that mix their own soil make use of compost or its constituents (such as humus or worm castings) as soil additives, and commercial soil mixes usually contain a good proportion of the same.
The basic premises underlying the enrichment of soil with compost are provision of micro- and macro-nutrients to your soil; improved drainage, aeration and texture of soil; and (last but certainly not least) development of the so-called ‘soil food web’—the fungi, bacteria and other beneficial microorganisms that naturally live in soil—which form symbiotic relationships with your plants and can seriously improve their overall health and yield.
Compost tea should never be a total replacement for traditional soil additives, but can be an excellent means of complementing and adding to your ‘soil food web’ when used as a soil drench. Compost tea also contains abundant micronutrients that can be absorbed through the stomata of the leaves when used as a foliar spray.
So what do I need to do?
You will need:
- 10 litres of good-quality, well-aerated organic compost, either pre-bought or home-made (home-made is considerably cheaper. If making your own compost ensure that it is fully mature before use)
- a 20 litre bucket
- an aquarium pump with 2 or 3 airstones or bubblers
- 250 ml of unsulphured organic molasses
- 10 litres of water
- a long pole or stick for stirring
- muslin, cheesecloth or a similar natural textile to strain the mixture
- fill the 20l bucket with the 10l of compost and top up with the 10l of water
- add the 250ml of molasses (you may need more in cold weather, as the microorganisms will require more energy to reproduce)
- stir the mixture thoroughly, making sure to thoroughly mix up the solids at the bottom
- place the aquarium pump inside the bucket and switch on, to provide aeration
- leave to steep for 2-3 days, stirring at least three times per day
After 2-3 days, check the aroma of your compost tea brew. If it smells unpleasant or fermented, add a little more molasses, stir, and leave for another day before checking again. You should never need to leave your mixture to steep for longer than 3 or 4 days.
When it has achieved a pleasant, light, musty aroma, it is ready to be strained through the muslin or cheesecloth and used. Your compost tea should always be used within the first few hours after being decanted; if this is impossible, add a little more molasses and switch the pump back on, so that the bacteria is provided with oxygen and nourishment. This way, you can extend its life for a few days—but never leave it for any longer than that!
- Disclaimer:Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.
16 thoughts on “How (and why) to make organic compost tea for cannabis plants”
Is the pump left on the whole 2-3 days? Or just a few minutes.
Good morning Brown,
I hope you’re having a great day,
Apologies for the delayed response, I missed your comment when updating the blog!
Yes, the pump is left to steep for 2-3 days, stirring at least three times per day.
I hope this helps,
Urine…… the most wonderful fertilizer in the world! 1 to ten of the same water volume and mix. Use as normal every week or two…… Watch your salt intake. Raise plant as normal.
Good morning Andrew,
Thank you so much for sharing your experiences with fertilizers!
To learn a little more about medicinal cannabis, here are some links that you might find of interest.
https://sensiseeds.com/en/blog/beginners-guide-home-made-fertilizer/ and The 10 most common mistakes when growing cannabis
With best wishes,
Juan said can he use his tea he drinks.Sure Juan drink your tea then urinate into a 2 liter bottle then fill it with water .Now you have good nutes.Wont be compost tea but it will be free nutes
Nothing like starting off my day reading and learning about something cool. Your blog post accentuated my breakfast perfectly! Thank you 🙂
Use just the tea bags only mix in with top soil
What if I want a small quantity of this tea compost water because I have one little plant just a beginner? I here you talking about liters of water and compost when it is just me drinking tea and wont produce so much of this tea compost? When you speak about tea: does it speak of all kind like some that I drink: ginger, chamomile, bladderwrack, yellowdock, sea moss, raspberry leaf, epazote, and more or you speak of just green tea itself? Also, someone like me that I have only one little plant how would the guide be like to be of doing ? Can i just dump the left over dried leaves into that plant soil after drinking my tea or make it the way you instructed to? Thanks.
Thank you for your comment. It looks like you have misunderstood the article, however; the ‘tea’ it refers to is an aerated mixture of compost and water, not the remains of tea that you drink. It might be possible to make on a smaller scale, but you will still need the same ingredients and equipment to make it work properly. Good luck!
Let me know how it tastes.
Hey be carefull using molases! It creates an anaerobic enviroment favouring anaerobic microorganisms, which we dont want in this situation!
True, but you can counteract this with enough aeration to your tea, as well as aerating what you normally water with. Anaerobic organisms tend to die off in environments rich in oxygen.
> If you feel like smoking compost.
can i spray on my flowering buds?
If you feel like smoking compost.