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DIY Compost Tea Recipe for cannabis

Compost is packed full of beneficial organisms and micronutrients. You can take the process a step further by soaking the compost in oxygenated water. This nutrient-steeping process is called “compost tea,” which extracts the microorganisms and soluble nutrients into a “tea” solution.

The goal of using Compost Tea in your garden is to introduce nutrients, fungal colonies, and beneficial bacteria into the growing medium(soil usually). It can also be used in a foliar application on the leaves of a marijuana plant to enhance growth and protect it from harmful diseases.

*Compost tea is a supplement to regular nutrients and not a total substitute.

Compost tea application to plants:

  1. Pour on the ground
  2. Spray on the leaves

When you pour compost tea directly into the soil, you contribute to the soil’s food chain by introducing a healthy population of microorganisms that are by their nature aerobic (life that requires oxygen). These tiny organisms hold nutrients, help to aerate the soil, aid in water retention, help the plant absorb more nutrients, aid in the new growth of healthy roots, and help prevent root disease.

However, the benefits of compost tea are a subject of debate in the cannabis world. Many home growers report quality issues resulting from using it, while others see no increased benefit than topdressing with just compost. The debate mostly centers around the uncertainty of whether a forming and developing population of microorganisms in the tea can actually benefit the plants and prevent diseases.

Compost tea recipe for cannabis plants

A well-made compost tea removes most of the soluble nutrients and microorganisms from the compost, including bacteria, fungi, and protozoa.

Here is your shopping list for your compost tea ingredients.

1. Compost: A good usable compost should have a large population of microorganisms and nutrients, this should be sourced locally to ensure that these organisms are local pathogens. Compost that has added mycelium populations (fungal colonies) helps with the development of fungal growth in the tea.

2. Worm Casting: This by-product of worm digestion, provides a high content of micronutrients in a broken-down, refined form that is readily available to plant roots.

3. Fish Hydrolyzate: This is slightly harder to find and is made from fish and crustaceans to create a nitrogen-dense product. It also contains chitin, which acts as an immune booster for cannabis plants. Fish hydrolyzate also helps feed the increasing fungal populations.

4. Kelp powder or liquid: This helps to nourish the fungi that develop during the brewing process of the tea. It is also theorized to provide a surface for fungi to attach and develop on.

5. Molasses: Serves as an extra food source for replicating bacteria that develop during the brewing process.

How to prepare the ingredients in 5 steps.

1. Build a compost tea brewer

Before building your own tea brewer, you need to calculate how much you will need for your entire garden. Most cannabis growers use a 20 L bucket. You need an aerator stone attached to an air pump on the outside of the bucket brewer. The aquarium air pump and stone oxygenate the water to allow microorganisms to breathe and replicate.

You require a mesh bag or a nylon stocking works great also, to place the ingredients for the compost tea. These brewers are also available commercially but don’t waste your money, the homemade one is super simple to make.


2. Create a schedule

Brewing this compost tea recipe takes time, so figuring out when you plan to use the tea is critical. Most compost teas generally take 24-36 hours to brew to perfection. You should not let your tea steep for longer than 48 hours as the populations of the microorganisms will explode to a point where they no longer have the conditions to live and will begin to die, affecting the end quality of the compost tea.

Only start with your compost tea recipe if you can use it within 36 hours of brewing. When used as a foliar spray, apply to the leaves in the morning or late evening at a lower temperature and away from direct light. During this time, the stoma (stomata-pores in the leaves of the plant) are also open and able to absorb nutrients directly.

3. Fill the compost tea bag

When making your first compost tea, don’t try to overthink things. If you’re using city water, let it rest in your bucket with no lid and evaporate all the chlorine, 24 hours ahead of time will be sufficient. Once your compost tea is done, keep it out of direct sunlight and make sure the air pump is still running and oxygen bubbles are visible coming to the top of the water.

Bucket Compost Tea Recipe

Non-chlorinated/filtered or rainwaterEnough to fill a 5-gallon bucket
Organic Compost2 cups
Worm Castings1/2 cup
Blackstrap molasses1 Tablespoon
Liquid Kelp Fertilizer1 Tablespoon
Liquid Fish Fertilizer1 Tablespoon

4. Brew the compost tea

There are several additives that can be introduced in the middle of the tea brewing process, extra food for bacteria and fungi can be added to increase the growth of microorganisms. Products such as seaweed and mycorrhizae can be added before the tea is applied to the plants for additional benefits.

5. Applying the tea to cannabis

The tea can be applied directly poured over the root zone or as a foliar spray to the leaves of plants. Dilute the tea with clean water in a ratio of about 1:20 when using it in a flood tray setup. Compost tea typically won’t burn your plants, so you can also use a high dose freely. As a foliar spray, the finished compost tea is usually diluted with 2 parts water to 1 part tea. Do not use compost tea with drip irrigation systems as the dripper tips will clog over time.

Benefits of Organic Nutrients for Cannabis Plants:

One of the best things about compost tea is that it improves the soil and the quality of your plants at the same time.

Other advantages:

Feeding cannabis with organic nutrients helps buffer the plants from being overfed by an anxious grower.

Throughout the growing cycle, organic fertilizers will improve the quality and variety of life in the growing medium.

It helps to improve water retention in the soil

Cheaply made, renewable and sustainable

Organic nutrients stay in the soil with less risk of nutrient waste.

Some cannabis plant growers are also finding that growing with organic nutrients improves the flavor profile of the finished buds and increases their yields.

Disadvantages of organic compost tea for cannabis plants:

There are a few complications when working with organic plant feeding. The main problem reported by home growers is that when your cannabis plant has a deficiency, it takes longer for the plant to recover while it absorbs added organic nutrients, which can increase the damage of a deficiency to the plant. Liquid nonorganic nutrients act much more quickly.

Other cons:

May attract unwanted insects and plant pests