Bokashi juice: dilution, uses and limits of “bokashi tea” for your plants

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At the bottom of your bucket, an amber liquid builds up over the days: this is bokashi juice, also known as “bokashi tea”. It is sometimes credited with every virtue under the sun. The reality is more nuanced: well diluted and poured at the base of plants, it is a useful little nutritional supplement; neat, it is too acidic and too concentrated for them.

This guide sets out what it really contains, the dilution to stick to, the right way to use it and what not to expect from it.

Where the juice comes from and what it contains

The juice is the water released by the waste as it ferments, pressed down under its own weight. How much you get depends mainly on what you put in the bucket: fruit and vegetables release a lot, bread and cooked leftovers much less. It often appears after a few days, sometimes only in the second week, and it is normal to have very little in winter.

Several analyses tell us what it contains:

• It is very acidic: its pH ranges from 3.5 to 4.9 depending on the measurements, an acidity comparable to that of orange juice.
• It is low in nitrogen: around 130 to 300 mg per litre, almost entirely in the form of ammonium.
• It is rich in potassium and phosphorus: roughly 2,400 to 4,300 mg of potassium per litre and 500 to 1,000 mg of phosphorus in the samples analysed.
• It can be salty: juice from cooked meal leftovers contained far more sodium and chlorides than juice from peelings.
• It is alive: it mainly contains lactic acid bacteria, the ones that fermented the bucket.

Did you know?

In an analysis of juice from four different kitchens, the juice from a household that mostly added peelings was the richest in potassium, phosphorus and calcium, and among the least salty. So the most useful juice for plants comes from peelings, not from meal leftovers.

The right dilution: at least 10 ml per litre

The basic rule, found in our instructions as well as those of most manufacturers, is a dilution of 1:100, in other words 1 cl of juice (10 ml) per 1 litre of water. For a 10-litre watering can, that makes 10 cl, or a small glass. This is a minimum: some sources recommend 1:200 or even more if you water more than once a week or if your plants are sensitive.

Diluting more carries no risk. Diluting less, on the other hand, exposes the roots to an acidic, salty liquid. If in doubt, use less juice, never more.

As for frequency, watering with juice once a week to once a fortnight is plenty. The rest of the time, water with clean water. In the diagram: a dose of 1 cl of juice (1) per 1 litre of water (2).

Emy's tip

Keep a dosing syringe or a small measuring glass by the watering can, set aside for the juice. You will measure accurately in seconds, without ever pouring “by eye”.

Water at the base, not on the leaves

Always pour the diluted juice onto the soil, at the base of the plants, on ground that is already slightly moist. Some manufacturers allow it to be sprayed on the foliage early in the morning, but leaves are much more sensitive than roots, and this acidic mixture can mark them. Our instructions advise against it, and we stand by that advice: soil only.

Diluted juice is suitable for vegetable garden plants, flower beds, shrubs and houseplants.

Seedlings and young plants: dilute much more

For seeds, seedlings and cuttings, dilute between 1:500 and 1:1000, i.e. 1 to 2 ml per litre of water. One teaspoon (5 ml) in a 5-litre watering can gives 1:1000; in 2.5 litres, about 1:500.

A published trial on tomato plants used exactly these dilutions: seeds soaked for half an hour in juice diluted at 1:500, then watered weekly at 1:1000. According to its authors, stem diameter was about 13% greater than in plants watered with plain water. The treated plants were also slightly taller, but this difference was not statistically significant, and the trial involved only a few plants. It is encouraging, nothing more. To find out more about seedlings and micro-organisms, see the EM guide article Seedlings, young plants and repotting with EM.

Use it quickly: within 24 to 48 hours

The juice is a living liquid that changes quickly once it leaves the bucket. We recommend using it the same day or the day after draining, and diluting only the amount you need. If you have to keep it for a few days, put it in a well-filled, closed bottle in the fridge or somewhere cool and dark. Some bucket manufacturers claim it keeps for up to a month in these conditions: we prefer to err on the side of caution. A distinctly bad smell or coloured mould is a sign that it should be thrown away.

If your tap gives almost nothing, that is not a problem: the bucket works perfectly well with little juice. We explain draining and how often to do it in the article Looking after your bokashi. A model with a tap, such as the Comfort Bokashi Composter, makes collecting the juice easier.

Drains and septic tanks: what we can say

Many instructions, including ours, suggest pouring the neat juice down the sink, shower or toilet. It is a good way to use it when you have no use for it in the garden: rather than throwing it away, pour it down a drain, followed by a little water.

However, we cannot promise that it unblocks pipes or maintains a septic tank: no study has shown this, and biological septic tank additives in general have no proven long-term effect. The subject is covered in the EM guide article Septic tanks, drains and dry toilets. Just remember that it is no substitute for a drain snake or a tank emptying.

What the juice is not

Bokashi juice is not a complete fertiliser. Being low in nitrogen, it cannot feed a plant on its own: in a pot trial, plants fed only with diluted juice grew noticeably less than plants given a conventional fertiliser. It mainly provides potassium, some phosphorus and soluble organic matter. Think of it as a supplement, alongside living soil, compost or vermicompost.

Nor is it compost tea: the liquid from a wormery, which is less acidic, is diluted differently, as explained in our article Harvesting vermicompost and worm tea. Do not mix up the two recipes.

Finally, if your bucket receives a lot of salty meal leftovers, its juice will be salty too. In that case, it is better to keep it for the drains rather than for potted plants, where salt builds up more easily. We also discuss this in the article What waste can go in a bokashi?.

Key points

Never neat, always at the base: at least 1:100 for established plants, 1:500 to 1:1000 for seedlings and young plants, used within 24 to 48 hours.

In summary

Bokashi juice is an acidic liquid, low in nitrogen but rich in potassium, that gives plants a small boost when used properly. Dilute it at least 1:100 (10 ml per litre) for established plants and 1:500 or 1:1000 for seedlings, pour it onto the soil rather than the leaves, and use it within two days. Any left over can go down the drains, without expecting miracles. And to truly feed your plants, rely first on buried bokashi and living soil.

Related products

Bokashi Composter Skaza Organko 2

Capacity 9.6 litres, individually or in a set of 2

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Urbalive Bokashi Composter

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Bokashi Confort Composter

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£34.06 €40.83

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Bokashi EM compost activator | 1 kg bag

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Other topics in the guide

Vermicomposting30 sheets →Composting25 sheets →EM micro-organisms26 sheets →