A handful of worm castings and a bucket of water turn into enough liquid feed for a 10-metre row of veggies. I make mine for the cost of nothing, because the castings come out of my own worm farm. If you’re buying castings, a kilo bag runs a few dollars and one brew uses about a cup. The tea is a mild, gentle feed you can pour on almost anything in the garden without burning it. Here’s how I do it.
What you need
The list is short. I’ve never needed anything fancy.
- A clean bucket, around 10 litres. A old paint bucket rinsed out is fine.
- Two big handfuls of fresh worm castings, roughly one to two cups.
- Rainwater if you’ve got it. Tap water works, but let it sit out overnight first so the chlorine gasses off.
- An old pillowcase, a stocking, or a bit of shadecloth to hold the castings. Optional, it just saves you straining later.
- A stick to stir, and somewhere shady to leave the bucket.
That’s the lot. No pumps, no molasses, no fish bottles. Plenty of folks add an aquarium air pump to keep it oxygenated, and that does make a stronger brew, but I’ve fed my beds for years on the still version and the plants have never complained.
The method
This is closer to making a cuppa than a science experiment.
- Drop your two handfuls of castings into the pillowcase and tie it off. If you skip the bag, just tip them straight in and strain at the end.
- Fill the bucket with your settled water.
- Dunk the bag in and give it a good swish. Squeeze it like a teabag a few times.
- Leave it in the shade. I steep mine for 24 hours. Anything from 12 to 48 hours is fine. Past two days it starts to go off, so don’t forget about it.
- Pull the bag out and tip the spent castings around a fruit tree. Nothing wasted.
The finished tea should look like weak black tea. If it’s darker than that, top it up with more water.
How to dilute and apply it
Worm tea is mild, so I don’t fuss over exact ratios. I dilute it down to the colour of weak tea, roughly one part tea to four parts water in the watering can. Then I pour it on the soil around the base of the plant, not over the leaves.
- Leafy greens and brassicas (lettuce, silverbeet, kale, broccoli) love it most. A water every two weeks through their growing stretch. These are the same crops that anchor most of the climate-zone growing guides, because they’re the cheapest to grow and the dearest to buy.
- Fruiting crops (tomatoes, capsicum, zucchini) take it well once a fortnight while they’re setting fruit.
- Seedlings get a half-strength version. They’re tender and don’t need much.
Apply in the cool of the morning or late arvo, never in the heat of midday. Use the whole batch within a day of brewing, because it doesn’t keep.
Timing the feed only pays off if the bed’s actually in season, so check what’s worth planting in your zone right now before you brew. Climate changes the timing more than the recipe. Up in the tropics and the warm subtropical zones, everything moves faster. Castings break down quicker, brews turn sour in well under two days, and the plants are hungry more often, so I’d feed closer to weekly through summer. Down in the cool temperate and cold zones, growth slows right off in winter. There’s little point feeding a bed that isn’t actively growing, so I ease off to monthly or stop until the soil warms. Match the feed to how fast things are actually growing in your patch, not to the calendar. If you’re not sure how fast that is, the live temperatures and rainfall from the Dayboro weather station give you a feel for when subtropical growth kicks back in.
The only real trick is remembering you’ve got a bucket of it on the go before it turns into a science project behind the shed. A free feed is only half the saving. Log the brews and the harvests against your running cost of a home patch and you’ll see the fertiliser bill you’re not paying. Build a worm farm, keep a bucket handy, and you’ll never buy liquid fertiliser again.
