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Compost Tea

Compost Tea for your Garden

Compost tea, at its simplest, is compost that has been steeped in water, usually between 24-48 hours, creating a liquid compost or tea that is rich in nutrients, microorganisms, and humates. Because of its liquid form, it can be applied by saturating the soil, or applied as a foliar spray. Regardless of how you apply it, compost tea benefits include improved plant growth, development, and creates plants that are more resilient to harmful diseases.   

In fact, it’s recommended that you apply your compost tea in both manners because it will fight diseases and dangerous pathogens found both above and below ground.

You most likely have a basic idea of nutrients, so let’s take a quick look at microorganism and humates before we move onto how we create compost tea.

Compost Tea Microbes / Microorganisms

They might be naked to the human eye, but microbes are vital to growing healthy and large plants when growing in soil. Microbes love working with plants, so let’s take a quick look at their relationship.

  • Microbes decompose organic matter and use the carbon and nutrients found in them for their own growth.
  • They will then release excess nutrients that will be readily available for your plants to use.  
  • Certain microbes consume dangerous pathogens found in soil. For example, certain protozoa consume pathogenic fungi that are dangerous to plant health.
  • Other microbes can degrade agricultural pesticides in soil along with other toxic substances.
  • Microbes improve soil structure and improve water retention.
  • Last, they are self-sufficient as well, because they digest each other’s dead bodies. This means you will use less organic material for nutrients.

Most compost tea is brewed with aeration supplies e.g. an air pump that supplies oxygen during the brewing process. Supplying oxygen uniformly throughout the tea will support the development of vital microbes that need oxygen to live.

When brewing compost tea there is no better way to create soil that’s rich with microorganism than by adding compost tea.

Compost Tea Humates

Humates are complex substances that we know are needed for plant growth and development and contain a number of organic acids: fulvic acids, humic acids, and macromolecules like amino acids, amino sugars, and peptides.

Understanding humates in their entirety is difficult even for those that are well-versed in soil growing, so for now, just understand that they are crucial for plant growth and development.

Brewing Your Tea or Pre-Brewed Tea

Many gardeners like brewing their own tea, either with ingredients that they put together or by purchasing a kit. This is a really great way to change the strength and type of tea, but it will take some work brewing it and you’ll need some equipment to do it.

Those that are on their first soil grows will have enough things that they need to worry about and may prefer to stick to pre-brewed teas. That’s why we offer several top of the line brands with different proprietary blends that work fantastically for promoting stronger root systems and an enhanced immune systems.

Brewing your own compost tea

Whether you want to create small batches of just a few gallons or create a leviathan size brewing operation, at Hydrobuilder brewing your own tea is incredibly simple. All of our brewers are stand-alone with easy to use pumps and drains that keep your work area clean and efficient.

Our equipment makes brewing a simple process just throw in your ingredient and walk away.

Let’s take a look at what the brewing process looks like with a more hands-on approach:

  • Step 1. Gather your brewing supplies and ingredients – You will need your ingredients (check out our kits that do the work for you), next you will need a bucket (preferably 10 gallons), last you need an aeration pump (an aquarium pump will do).
  • Step 2. Fill your bucket with water – If using tap water let it sit out for a day, so the chlorine can evaporate away as it can kill good microorganism.
  • Step 3. Add a catalyst – Your catalyst is simply a nutrient solution for the microbes and gets them eating and multiplying.
  • Step 4. Steep your compost – You will put your compost in a brewing bag, ball, etc. just like if you were actually making tea – screen/bag size should be close to 400 microns as possible..
  • Step 5. Aerating the mixture – This is crucial and you want air to pump up from the bottom and up throughout your brewing mixture. This will get beneficial fungi and bacteria moving and doing their job.
  • Step 6. Walk away – The brewing process should last for at least 24 hours. The longer you brew the more potent your tea. You will want to see form as that indicates that the tea is brewing properly.

Creating your own compost tea mixture

Remember, the goal of compost tea is to provide your plants with nutrients, fungal colonies, and beneficial bacteria to create a thriving community and while brewing is a simple process gathering everything you need isn’t always the case.  

It’s entirely up to you whether you want to create your tea from scratch or purchase a kit. A lot of gardeners purchase kits because they are a lot of ingredients that go into making a fantastically rich tea and unless you’re making a lot, it’s simply not cost-effective buying everything. At its most basic you will need compost, worm castings, fish meal, kelp, and molasses.

If that seems like a lot, just take a look at all the ingredients a compost tea nutrient solution will come with. You’ll see fish meal, feather meal, bone meal, crustacean meal, alfalfa meal, cottonseed meal, kelp meal, dolomite, gypsum, and we’re going to stop there.

Tea kit solutions will come with different ratios of fungi to bacteria and the food to feed each, and the type of plant you grow will determine what ratio you need.

Type of Plant Type of Tea
Coniferous Trees Highly Fungal
Deciduous Trees Moderate Fungi
Berries Balanced Ratio of Fungi and Bacteria
Vegetables & Grasses Moderate Bacteria
Brassicas Highly Bacterial


If you cannot find your specific plant above, simply find the type that is the closest to what you are growing. As well, if you’re growing in sandy soil you will want a heavier ratio of fungi because it will help improve and build soil structure.

This should give you an idea why many go for kits, and that’s why we offer a bunch of differently priced kits, with various mixtures of ingredients so you can start brewing on a budget.  

Applying Compost Tea

You can apply your tea to either the roots by just regularly watering or as a foliar spray – doing both will improve your plant’s resistance to diseases both above and below ground. If applying as a foliar spray, it’s recommended to do so either in the morning or late in the day to prevent UV degradation of the compost tea.

For most growers, compost tea will not replace the main nutrients they feed their plants with, as such they brew what is called a basic tea. Basic tea will not harm your plants with nutrient burn so you can apply your tea freely. Compost tea is not considered a fertilizer nor is it considered a fungicide. It simply provides your grow media with additional microbial activity which results in better plant growth and development.

It’s common to see gardeners dilute their tea with water between 1:1 to 1:20, but this is not required and in fact many gardeners don’t. To apply as a foliar spray it is recommended to dilute your tea anywhere between 1:2 to 1:10.

Last, compost tea has a poor shelf life and should be used within 6 hours after brewing. Without aeration, oxygen levels can lower by 300% after just 6 hours. You will need to aerate, agitate, and add more food to the tea if you do not use the tea within said time frame. Aerobic microbes are the most beneficial microbes to have in your tea so aeration is key.