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Compost tea has been shown to have several great attributes for your garden (and dozens more than gardeners claim to see).
But what type should you use for your garden?
What Is Compost Tea?
Compost tea is pretty much exactly what it sounds like. It’s a “brewing” of finished compost in water for a day or two. Proponents of anaerobic compost teas claim that, during that time, the most valuable part of the compost, the beneficial microbes, are pulled into the water. These microbes, along with the nutrients in the water should, in theory, maximize the growth potential of your plants.
Most notable benefits of compost tea:
- Disease Prevention for Plants and Soils
- Promotion of Microbial Diversity
- Reduction of Toxic Run-off From Commercial Fertilizers
- Increased Plant Production Due to Added Nutrients
- Balance of Acidic Soils
The 4 Types of Compost Tea
There are three different types of compost tea that people make. Each one of these is made by putting the main ingredient (compost of some sort) in water and letting it sit. However, there are differences:
Aerobic Compost Tea
Aerobic compost tea (properly called AACT or Actively Aerated Compost Tea) is the most commonly used and typically the most recommended type of compost tea. Aerobic here means “in the presence of oxygen” and refers to the fact that this tea is oxygenated throughout the steeping process. The most common way to accomplish this is by placing an aquarium pump in a bucket so as to circulate oxygen into the water. That way, when the compost is added to the water (inside a mesh or burlap bag), aerobic microbial life will be favored.
Anaerobic Compost Tea
Brewed without oxygen, Anaerobic compost tea has a lot in common with homemade bokashi bran and is a very viable option for those who want a simple (or lazy) way of making compost tea. However, you can’t have your cake and eat it too. Anaerobic compost tea has several distinct disadvantages which we’ll discuss later.
Anaerobic teas are typically split into two types based on the medium that was used to brew them: bacterial teas or bloom teas (a more fungal tea). Both have similar benefits. The type you choose to brew will affect the steps required and is usually dictated by what you have on hand. I typically make a bacterial compost tea, as it is easier to make and more in line with the compost I have available.
Manure tea is very similar to the above teas except that it is a bag of manure (instead of compost) that you steep in water. My opinion (and the opinion of most experts) is: don’t brew manure tea. The same magic that will cause all the beneficial components to mix with the water will also draw out all the pathogens in the manure.
The most common (and concerning) one is e.coli.E.coli is commonly found in manure and can lead to extreme sickness and/or death. So while I don’t recommend any compost tea be used on food plants, I would not recommend manure tea for anything at all.
Bokashi tea is the liquid that is drained from a bokashi bucket during the fermenting and composting process. It is incredibly rich in microbes and nutrients and can be added to plants and soil (provided that it is properly diluted first).
Compost Tea FAQs
What should I use compost tea for and how often?
Compost Tea can be applied to your yard or garden every 2-4 weeks. During times of plant stress or disease, you may want to apply it more frequently.
If I am going to be applying compost tea to my garden (or plants that will be consumed by humans), I steer clear of anaerobic teas. If you want to give your food garden a boost, get an aerator and make some proper AACT.
Can I make compost tea with store bought compost?
In theory, yes. Bagged compost would make something that resembles compost tea. However, store-bought compost is hit or miss (quality-wise) and is notoriously low in microbial activity. You’ll have far better results if you use freshly finished or active compost, especially one that you have made on your own so you are aware of the ingredients.
What types compost should not be used for compost tea?
Fully decomposed hot compost is the compost of choice for creating compost tea. Don’t use compost that contains manure, meat products, etc. One of your main goals is microbial growth, and you don’t want an explosion of pathogenic growth as well.
This is less of an issue if you are adding the compost tea to the flowers in your front yard, but you’ll still want to be careful when handling the tea or keeping it around.
What should you do with the “used up” compost?
In a perfect world, your compost tea would contain all of the microbes and beneficial nutrients of the compost, leaving behind only a fibrous husk. The truth is, however, is actually much better. Your “spent” compost will have the same microbial concentration as the finished compost tea.
Because you have encouraged such an explosion of growth, it’s very probable that your compost is actually richer in beneficial microbes than when it when into the water. I typically reintroduce my compost to my pile with some added scraps to feed all the new microbes. Just be aware that you will need to work hard to keep your pile balanced and aerobic if you’re introducing too many anaerobic bacteria.
In conclusion, compost tea is not only beneficial but it’s incredibly easy to make. The real trick is to identify which option is the easiest for you to make with what you have one hand. Perfecting your compost and garden is a balance of deciding what is perfect and what is possible. All compost teas are beneficial in some way or another, so find the best one for you and go for it!