LESS IS MORE: Gardens love weed tea

Put any weed or grass clippings into a bucket, add water, cover with a lid and wait two weeks. Picture: Tricia Hogbin
Put any weed or grass clippings into a bucket, add water, cover with a lid and wait two weeks. Picture: Tricia Hogbin

A FEW weeks ago I wrote about making herbal tea from foraged weeds.

I’m making weed tea again but I won’t be drinking this batch. This brew is for the garden.

In a couple of weeks’ time  I’ll have bucketfuls of stinky liquid fertiliser, rich in minerals and microbes, ready to boost the productivity and resilience of my garden. 

Turning weeds into nutrient-rich liquid fertiliser is a great way to use a resource that may have otherwise gone to waste. 

Basically, weed tea is made by fermenting weeds in a bucket of water. The fermentation process creates a liquid fertiliser rich in soluble nutrients and a diversity of beneficial microbes.  The result is not only a boost in productivity  but also increased resistance to disease and insects. 

I’m making my current brew using stinging nettle and fireweed, which are abundant in my neighbourhood at the moment. But any weed will do. Other weeds I’ve heard of being used include clover, chickweed, lantana and scotch broom. Fleshy, deep-rooted weeds like dandelion and dock are especially good because their roots mine valuable nutrients from deep in the ground. 

Weed tea is also a great way to use grass clippings or weeds that you prefer not to compost for fear of spreading weed seeds. Forexample, I’ve been tossing fireweed into alarge sealed bucket. A best practice management guide for the control of fireweed suggests it should be placed in a sealed bag and burnt or buried. By first making weed tea, I’m extracting all the nutrients before disposal.

The first step in making weed tea is to fill a bucket with weeds. A plastic bucket with a lid is ideal. Pack the weeds down as tight as possible. Continue filling and packing until your bucket is around two-thirds full of tightly packed weeds. 

Your tea will naturally be colonised by beneficial microbes but you can speed up the process by inoculating it with preservative-free fermented foods such as sourdough starter, sauerkraut, kefir, yoghurt or organic beer or wine. I added a generous spoon of home-made sauerkraut. 

Fill your bucket of weeds with water. If using chlorinated town water, first leave  a bucket of water in the sunlight for at least a day so that any chlorine can evaporate. 

Hold weeds under the water surface using a brick or large rock, then place a loose lid or cover on the bucket. Make sure it’s not air-tight as the fermentation process releases carbon dioxide – and I’m sure nobody wants an exploding bucket of smelly liquid fertiliser. 

Leave your bucket of tea somewhere warm to ferment for a week or two. 

Before using, strain your weed tea through an old thin T-shirt or pair of stockings. Straining ensures you don’t disperse weed seeds or clog the nozzle of your watering can. Dilute your strained tea until it is the colour of a weak black tea. Dilution rate will vary between batches and will be influenced by the type and quantity of weeds used. Over-diluting is far better than not diluting enough, as strong fertiliser can burn young roots or shoots. 

Your diluted weed tea can then be poured over the root zone of growing plants. Don’t apply to vegetables about to be harvested as I’m sure it wouldn’t taste good. Diluted again to half-strength, it also makes a great fertiliser for indoor plants and seedlings. 

Tricia shares tips for living better with less at littleecofootprints.com and on Instagram (TriciaEco)