“Compost tea has been hailed as the magic elixir that makes plants grow stronger, ripen faster, taste better, run farther, and jump higher”
Compost tea is a name that gets thrown around a lot when talking to gardeners. It can bring a certain coffee shop vibe into the garden when conversations switch from pests and seed germinations to strengths of brews and step times, but what is compost tea? Simply speaking, compost tea is a liquid mixture of compost in water, making the nutrients of the compost more available for the plants. Though this description is not wrong, it is a bit of an over simplification for what is actually going on in compost tea.
Firstly the term tea can be misleading for compost tea. Though you do brew it in a similar way to tea, with a large tea bag (usually a sock or shirt) steeped in water to infuse the water with elements of the “tea” in this case the compost, compost tea behaves more like brewing beer or making a sourdough starter. That is because what is really going on in the compost tea is closer to a fermentation. Compost tea create a complex microbiome of thousands of bacteria, fungi, and nematodes. Just like in our own bodies these microbes are essential for the plants growth and its ability to absorb nutrients. So how do we get this microbiome into our compost team?
Fortunately for us, all of the work of inoculating our compost tea with cultures of healthy microbes has already been done by our compost, or worm castings, so our job is to make sure that these we create a healthy environment that these microbes can thrive in.
As I mentioned above there are different levels of complexity with how you brew your compost tea, but whether you want to go as simple as mixing compost and water into a bucket, or you want to go all the way to using an aerator and fish meal, the first and most important step of compost tea is the same for how ever you do it.
The first step with compost tea is to make sure that you are working with chlorine free water, so that you are not killing any of the microbes that we are trying encourage. If you are getting your water from somewhere other than the tap like rain water, or from the ditch, this isn’t an issue. However if you are getting your water from the tap, or any potable source, then your water has chlorine in it. The two simple ways to get rid of chlorine in water are to either let it sit in the open for 24 hours, and the chlorine will burn off. Or if you don’t want to let it sit for 24 hours vitamins C powder can be added, because the abzorbic acid in it will neutralize the chlorine in about 10 minuets. Use about 50 milligrams per liter of water to neutralize the chlorine. This method is also beneficial because the vitamins C is also a beneficial nutrient to the plants.
Aerated vs non-aerated
Non-aerated
The biggest distinction between the two types of compost tea is whether or not there is an aeration system. This can be an important aspect to compost tea because all of the beneficial microbes that we are trying to grow in the tea are aerobic, meaning that they need oxygen to survive. Which is incredibly important, because if the compost tea goes anaerobic, then harmful bacteria such as e-coli will take over your compost tea. This is not to say that the only way to safely brew compost tea is to use an aerator. Just if you choose not to use an aerator, make sure that you are not over brewing your tea. There will only be enough suspended oxygen in the water for approximately 24 hours, so this can be a great method if you are wanting to do a quick and simple brew. Just be sure to follow your nose with this one, and if the compost tea is smelling bad, then it has gone anaerobic, and shouldn’t be put on your plants. A recipe for this simple brew could be as easy as
5 gallons of chlorine free water
1-2 cups finished compost (or worm castings)
5 gallon bucket
Nylon sock or pillow case to act as tea bag.
Aerated
If you are looking for a bit longer brew time, or want to get a little more fancy with the microbes that you are growing, then you are going to need an aeration system. The easiest option for aeration would be an aerator for a fish tank. The kind with the porous stone at the end of it that the air gets pumped through are great at introducing oxygen into the water. These will allow your compost tea to brew for a longer time, and produce more microbes without going anaerobic. But going anaerobic is not the only concern with longer brewing times.
A longer brew time opens the door up to a plethora of benefits, as well as problems. To simply put it, more microbes more problems. The benefits of doing a longer brew is that your compost tea will have more microbes in it, and the cultures can be healthier, but more healthy microbes are going to require more resources. When doing an aerated compost tea, it is important to feed the microbes. In the more basic set up, there is enough food in the compost for these microbes to munch on for the time while they are brewing, but extending that brew time with an aerator is going to leave them hungry. Supplementing your compost tea with food for these microbes is easy. Bacteria need simple sugars to feed on. This can be done with unsulphured molasses, or really any simple sugar. The fungi in the compost tea are a little more tricky, and require complex sugars. These complex sugars can be found find in liquid kelp, or fish fertilizer, these make great additions to your compost tea. Here is a recipe if you are looking to do something a bit more involved with your compost tea
5 gallons of chlorine free water
Two cups of compost
One tablespoon unsulferd molasses
One tablespoon organic liquid kelp fertilizer
One teaspoon organic liquid fish fertilizer
A bag for the compost (something like a sock or a pillow case)
Utilizing compost tea
Now that you’ve got a fresh batch of dank compost tea what do you do with it? Compost tea is a liquid fertilizer, so it has a very straight forward application process. You water your plants with it. Well, it is a bit more complicated than that. Depending on who you ask, your compost tea can either be put directly onto your plants, or it needs to be diluted up to a 10:1 mixture. A lot of this depends on how concentrated your compost tea is. I would recommend beginning with a 4:1 or 5:1 ration to make sure that you do not burn your plants. Though nutrient burning your plants with compost tea is difficult, it is not impossible. Starting with a diluted compost tea, then experimenting with your ratios will be a good way to insure that you get max nutrition without the burn. Watering your plants bi-weekly with the compost tea mixture will help to facilitate the growth of your garden, and the compost tea can be applied to the foliage as well
It can be tricky right off the bat to see if your compost tea is working. Considering most of us don’t have 400x magnified glasses we cannot see what microbes are swimming around in our tea. It will take a couple applications at least to begin to notice any difference, But I would recommend doing some side by side comparisons to see the differences for yourself.
