How To Make Worm Tea – (What Is It And Does It Really Work?)

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Some people use the excess water from the worm castings in their worm farm or bins, directly as liquid fertilizer or put it into a watering can or spray bottle to use as a spray fertilizer to help boost their plants’ growth. 

This is known as Worm Tea by vermicomposting enthusiasts or compost tea by those who do their composting without worms. 

Earthworm castings are neutral and contain various minerals and trace elements that are not available in chemical fertilizers which makes this worm compost tea a popular choice for those of us into worm farming.

If you’re interested in giving your garden that bit more of a boost, why not make some worm casting tea? Here is everything you need to know in our ultimate article and guide.

How to make compost tea with worm castings

  • Choose a suitable bag for your compost material. It is essential that this bag is porous. It will become your tea bag – and ideally, it will be made from natural fibres. You will need a piece of string to fasten the top, as you prepare to steep the teabag and worm castings inside.
  • You will need a worm bin to hold, ideally, red wiggler worms or whichever worms you prefer in your worm farm or bin. The worms will be producing castings from composting the organic materials like food scraps that you provide for them in your worm farm.
  • Choose a large water vessel, as you are going to use large quantities of water. Approximately five gallons is good to start with, and it is important to use rainwater or some other dechlorinated water. Water butts are a good source and if you have one with a tap at the bottom, you can simply attach a small length if hosepipe and draw the amount you wish to use.
  • Simply load the worm castings into the bag and secure the top by tying it with the string. Inevitably, some soil will be in the mix but try to avoid getting worms in there.
  • Drop the teabag into the ready filled water container and move it around a little if possible.You may wish to consider using an aerator to increase the level of oxygen. An aquarium air pump with an air stone works great. If you want to brew more tea at once, go for the commercial air pumps that allow you to aerate multiple bags of liquid. The more oxygen in the mix, the better. Oxygen increases the microbial efforts to produce good quality tea. This is key.
  • It will take several hours to produce good strength tea. Some people make it early in the morning for use in the evening. Alternatively, you may choose to leave the mixture overnight and it will be ready in the morning. You will know the mixture is ready when the liquid has turned a rich brown colour.
  • Using approximately the same amount of water used in the preparation of the tea above, you now need to dilute it. Apart from increasing the quantity of useable fertilizer for your garden, it will last longer. Unused fertilizer should be stored without a lid, though it could be placed under a shelter. By not placing a lid on top, you can maintain great oxygen levels.

How to use worm tea

When it comes to actually using worm tea, you are going to need to find a receptacle to spray or water the mix into your garden.

It will be easier to handle in smaller containers – spray bottles or watering cans are ideal. The slow flow of watering cans can seep through soil and deliver welcome nourishment  to the roots of plants, fruit-bearing shrubs and young trees as well as houseplants.

You may have been surprised to read that using spray  bottles is recommended, too. This is because worm tea is a great tonic for leaves. Worm tea is known to even cure some plant diseases – it really is a great

How often to use

In general, plants will enjoy a drink of worm tea every two weeks. Well established plants will usually require a greater quantity than smaller or younger plants.

Of course, house plants should be watered in accordance with the plant care you are familiar with and this fertilizer will usually form a smaller fraction of their usual drink.

For example, if you water a houseplant once per week, on alternate weeks it is recommended to water with only water one week and a diluted worm tea fertilizer the following week.

It is important to not overwater or underwater your plants.

The nutrients in the soil are taken up by established roots, so replenishing the nutrients in the soil is important. There are no two ways around this – worm tea definitely enriches the soil.

Of course, the more nutrient deficient soil has become, the longer it will take to show a marked increase.

It is better to use diluted worm tea over a longer period, than giving a short burst of undiluted tea.

If you are adding worm tea to a barren piece of land, you won’t see the effect until it’s planted. Of course, you may see some weeds flourish – so be careful.

The Difference Between Worm Tea and Leachate?

Worm tea is produced by collecting castings and steeping them in clean water.

Leachate, on the other hand, is the name given to the liquid residue at the bottom of compost bins or composters.

It can be ‘stale’, anaerobic and smelly, though it does contain some nutrients and may be used as a fertilizer, it is nowhere near as effective for your garden as oxygen-rich worm tea full of beneficial microbes.

What nutrients are in worm compost tea?

Worm casting tea obviously contains worm poop, but also beneficial microbes, nitrates, phosphorous, magnesium, potassium, calcium as well as nitrogen-fixing microbes. There is more to your tea than you imagine.

Does worm tea really work?

Using worm tea does indeed work very well. It has proven to be a great food source for plants, helping them to grow stronger.

It has also been proven to help save polluted soil, repopulate the soil with microbes (enriching the soil and serving as great plant food), is fantastic for water retention in the soil, and is a great way of using a completely natural fertilizer.

How long does worm tea last?

Since worm tea is full of live bacteria, the microbes will begin to die within the first 24 hours.

The reason that professionally manufactured worm tea is able to stay alive is that they brew with oxygen through a fish tank bubbler (also known as an air pump).

For the best result, you will need to use worm composting tea as quickly as possible (past two or three days, it will be nearly useless).

Do I need to dilute worm tea?

Using a 5-gallon bucket, you will need to put five or six cups of worm castings (worm manure) in about four gallons of water, to create a well-balanced tea that will help with the plant growth and not damage the soil structure.

You can put the castings in water in two ways; by using panty hose or a t-shirt to create a strong but breathable tea bag.

Can worm tea burn plants?

Will too much worm tea help or burn your plants? The good thing about worm tea is that it will never burn your plants.

Unlike regular fertilizer, worm tea poses no threat to your garden.

Can you drink worm tea?

No, you cannot drink worm tea. Or, it’s at least not recommended.

Worm tea is a type of fertilizer that is ideal for plants and crops but can be dangerous for humans if ingested. Stick to your usual teabags, milk and sugar and leave it off of your home menu – would be our advice.

Have more worm composting questions? Why not search our other posts about what worms eat (do they eat leaves, fruits, cardboard? Or what do they eat in the wild?) or our hundreds of worm farm, composting and other worm-related articles