Good morning worm composting friend, we’re going to look at how to make real worm tea.
But first, let’s talk about the end result of a worm compost. Those lovely light, fluffy castings full of beneficial microbial life.
Vermicompost, as it’s also known as.
Unless you’re running a continuous flow through system, then about every 12 weeks you can be harvesting your worm bin to get all that vermicompost out so you can use it.
There are at least 4 different methods you can use to harvest and then variations of those methods. I tend to bait first, for about a week, then finish with sifting.
Not always. It does depend on what bin it is and who’s in there.
Once you’ve completed the harvest and the worms from that bin are all in their new bin, that’s the point of real marvel.
If you’ve operated the worm bin over the last 12 or so weeks, in line with the principles for success, you’ve now got a tub full of light, fluffy, tumbley, slightly moist, easy to work with, life filled, vermicompost. Earths most powerful and natural fertiliser. And soil builder. And pest repellent. And disease suppressor.
Magic. Black gold. The best of the best.
A tub full of it, ready to use.
And the inputs probably cost you nothing and overall it likely took very little effort to get to this point.
Vermicompost is loaded with beneficial microbial life, and humus, and plant growth hormones. Pretty dang close to what Nature does out in the wild.
If you’re anything like me, you might be standing there taking handfuls and letting it tumble through your fingers, feeling pleased / humbled / impressed / excited to use it.
At this point, immediately after harvest, it is ready to use. It doesn’t need to “cure” or “mature”. And it wont burn your plants, no matter how much you use.
There is no “too much”, however there is “adding more than the soil system can use at that time” ie wasting it.
Although really, nature won’t waste it.
But you can use it in a measured way and get maximum benefit in your soil from it.
The effect of regularly adding worm castings and or worm casting tea to your soil is cumulative and expanding.
When I say expanding, I mean that if you have close neighbours and you spend enough time adding this magic to your soil, eventually your neighbours soil will begin to be impacted. Ha!
How much time would that take? Well, without actually taking soil biology samples around the place over time, we can’t know how long it would take.
I don’t worry about details like this. I just get on with using it.
We do know that nature doesn’t waste time or resources.
I trust what’s happening in my own soil and in the soil everywhere vermicompost is being used.
A little understanding of the soil food web contributes to this trust. Check out Dr Elaine’s Soil Food Web School on Youtube if you’re interested. Here’s a link to her channel.
So let’s use this black gold.
It’s helpful for most people as they are starting to use it, to have a guide on how to use it and how much to use. In time, you might intuit this and forget about guidelines. Which is awesome and perfect, by the way.
When you’re preparing a garden bed, apply 1 to 2 litres of your vermicompost to every square meter of soil. You can use a rake to turn it in a bit, or you could just sprinkle it on top and be done with it.
You don’t want the vermicompost to dry out or have the sun beaming all over it. This black gold was created in a dark moist environment, so you’d be wise to do what you can to replicate this in the garden bed.
Easy. Water the vermicompost in and cover the garden bed with mulch.
Maybe your garden bed is already up and running, and it’s too late for prep, but you’re ready to use your vermicompost in there now.
No problem. You could move the mulch out the way, sprinkle the castings on the soil, water it in, put the mulch back.
But this might be a big nasty job if your garden bed is big or if the plants are already in.
You can put a handful of vermicompost in each hole your plants or seedlings or seeds are going in. And you can do this whether or not the garden bed was originally prepped with vermicompost.
If you’ve already planted, still no problem. Just sprinkle a handful or two around the base of each plant. And you guessed it, water it in and cover it with mulch.
Worm castings tea is the ultimate way to use vermicompost.
But first, let’s quickly look at potting soil. Because maybe you have a bag of potting soil mix from the shop that you’re about to use, and you know it’s going to be an even better mix if you put some of your lovely home produced vermicompost in it.
Simply mix in 10% to 20% by volume of your worm castings.
So if you have a 25 litre bag of potting mix, you’ll want to add between 2.5 litres and 5 litres of the castings. Just roughly measured is fine. Maybe tip the whole potting mix bag into a wheelbarrow, then add the vermicompost, then mix.
There’s something to consider here. You want the vermicompost to remain moist. Usually the stuff in the potting soil bags is totally dry. (Ding ding, light bulb moment here!)
If you’re not about to use the entirety of that bag of potting mix and some of it is going to sit around for days or weeks before it’s used, maybe just add the vermicompost to the amount you’re going to use today.
Ok let’s talk about the tea. This is the real bullseye of the whole process of producing your own worm castings.
Worm castings tea. Aka vermicompost tea. The REAL stuff.
“Worm tea” is probably the most common term used. But it’s not made of worms, and it’s usually used to refer to the leachate that dribbles out of a tiered farm. Tiered farms should NOT be used. Leachate always holds the potential to cause problems you don’t want.
Worm castings tea is easy to make. In fact, the extract is even easier.
What’s the difference, I hear you say…
Extract is simply moving the microbial life from the vermicompost into water, then applying that extract water to your garden and plants.
To make extract, fill a bucket with unchlorinated water, add a handful or 2 of your vermicompost, and stir a little. Let it be for anywhere from 1 to 6 hours. Come by a few times and give it a stir.
Then use it. Don’t dilute it, just pour it on as it is.
However! While extract is awesome and is full of life, worm castings tea is exponentially better than extract.
Worm castings tea is better than anything you can buy. The stuff you make yourself is definitely better than any bottle at any shop or market that is labelled as “worm tea”. I absolutely guarantee you this.
You’ll need a 20 litre bucket – or a 200 litre drum or a 1,000 litre pod, adjust the rest of the recipe accordingly.
But let’s just work with a 20 litre bucket because that’s super doable.
You’ll also need an air pump that has a flow rate between 5L per minute and 10L per minute (for a 20L bucket). A fish tank air pump does the trick and will cost somewhere between $20 and $70, depending on the exact flow rate and where you buy it from.
And you’ll need about 2 tablespoons of unsulphured molasses. It has to be unsulphured. Look on the label, if it is unsulphured, then it will specifically say “unsulphured”.
Fill your 20L bucket with unchlorinated water, mix in your molasses, then put 1 or 2 cups of your vermicompost either directly in the bucket or into a “tea bag” such as an old sock or a purpose sewn calico bag.
Tie the tea bag to the bucket handle so that it hangs about halfway down in the water. Put the ends of the air hoses it the bucket – you may like to secure them to the bottom of the bucket with a rock but make sure the rock isn’t so heavy that it’s pressing on the hose and closing off the air flow – then turn the pump on.
You are now brewing up some real worm castings tea!
Give it 48 hours. In this time, the microbial life is going crazy eating that molasses and reproducing. By the time 48 hours is up, you’ve gone from having a million billion microbes to having a trillion gazillion bajillion microbes.
After 48 hours, you can dilute this potent magic down with water, anywhere from 1 part tea and 5 parts water up to 1 part tea and 10 parts water.
Your diluted tea can be watered directly onto the soil, or watered onto the plants and it will make it’s way into the soil. You could even put it in a sprayer and spray it on the underside of your plants.
You could use it undiluted if you were suddenly unable to go hang out in the garden for a while, watering the liquid black gold everywhere. That would be a waste, but it would be no harm at all.
Remember that these microbes originated in the dark? It’s a very good idea to apply this tea to your garden at dawn or dusk to avoid the direct sun. I apply my teas in the evenings.
If you did this every 2 to 4 weeks over a growing season, you’ll have a much bigger and better result. Whether that’s a bigger harvest of food, or winning a rose competition, or recovering a struggling piece of lawn.
Sometimes you just have to see it to believe it, because the claim might seem a bit far fetched.
But you started with a tub, some worm bedding, and some worms. You put your kitchen scraps in there probably about 12 times, give or take. Then you moved the worms out and delighted in the finished vermicompost.
Cost of worms (and maybe the tub) aside, because you’ll use these over and over and over, how cheap was this to produce?
And then considering you’ll use that bucket and air pump over and over and over too, how cheap was the liquid gold to produce??
Go give it a whirl!!
As you continue to put either (or both) the vermicompost or the tea on your soil, the soil food web gets stronger and stronger. The impact of your effort is cumulative and expanding.
While you may just be focused on growing more and better food crops, actually you are bringing regenerative practices to the soil in your back yard. And the impact of you continuing to do this goes far beyond what you’ll ever know.
We can make a massive positive difference to our immediate environment, and to the local environment, and to the whole picture of soils in the world. Just by worm composting and putting the end product in our garden.
So easy! So fun. And so so good.
If you’d like a downloadable version of this, you can grab my free guide on How To Use Worm Castings In The Garden.