Keeping Water Clean & Safe

With water meters and summer hosepipe bans, collecting and saving rain water for the garden has become a must. Many greenhouses and sheds now boast a water butt, saving rainwater for the dry periods. But there is a problem…

Water Butt

Water Butt – Collecting Rain Water

Left sitting in the water butt, algae and bacteria start to grow in the water and it can quickly become green and stagnant with a repulsive smell. This doesn’t just make the water unpleasant to use. Some of those bacteria can be harmful to plants, especially seedlings. There is little point in using a quality, sterile seed compost if you then give your seedlings dirty water and cause damping off.

Envii are a British company with a reputation for innovative horticultural products using micro-nutrients and bacteria that stimulate growth and protect plants from pests and diseases. They’ve turned their attention to the problems of storing water for garden use and come up with a really clever solution.

Chemical Solution for Water Butts

You can keep water sweet by adding chemical sanitisers – I’ve used potassium permanganate in the past – but there’s a problem with those as well. We know now that the soil has a complex ecology where bacteria and fungi help plants to use the nutrients there. Watering with a bactericide is probably not the best idea!

Biological Solution for Clean Water

So Envii have developed a biological solution to keeping water sweet in the butt and stopping algae growth. Friendly bacteria working for you that won’t harm your soil ecology or plants. Even if the water has become green and stagnant, the bacteria will clear it.

Growth & Health Promoting Bacteria

They didn’t stop there, though. Envii realised that by adding another strain of bacteria they produce, they could actually improve plant growth and crop yields whilst reducing the risk of disease and pathogens. A double benefit!

Is it Safe?

It’s a completely natural and organic product. The treated water can be safely used on salad crops and vegetables. Whilst the water from a butt isn’t going to meet the stringent safety standards we have for drinking water, it’s fine for pets and wildlife. So you can give the dog a drink on the plot from the water butt.

In the Greenhouse

Water Butt inside Greenhouse

I always put a water butt inside a greenhouse. It does two things. Firstly the water heats up in the day and releases that heat at night. This helps to even out the temperature drop at night. Not a lot, but it helps.

The main reason is temperature, it gives me a handy source of water at room temperature. Watering seedlings and even full grown plants with water straight from the tap at around 4 or 5 degrees can shock them and effect growth.

Using Water Butt Klear with Tap Water

I fill the greenhouse butt with a hosepipe from the mains, so I know it’s free of any harmful bacteria. However, when you’re not using a lot of water at the start and end of the season, it too can go stagnant.

I was concerned that the chlorine in tap water would kill the beneficial bacteria and stop the Water Butt Klear from working, so I telephoned Envii and asked. They explained that the normal low level of chlorine in drinking water evaporated fairly quickly was unlikely to be a problem.

However, there are times when it varies and you can smell the chlorine. If you use a spray nozzle when filling the butt, this aerates the water and evaporates any chlorine. Alternatively, just leave the water in the butt for 24 hours before using Water Butt Klear and it will have gone.

There’s not many companies where you can pick up the phone and speak to an expert on the product!


Water Butt Klear comes in a compostable pouch. Envii take the environment seriously and are putting a lot of effort into ecologically friendly packing. See their sustainability page.

For more information and to buy – see Water Butt Klear

See Also

Trial pea seedlingsPro-biotics, The New Wave?

A look at some new biological growing aids that are now available to the gardener. Based on micro-nutrients and micro-organisms, supplements to protect plants from pests and disease whilst promoting growth. Read More…

Posted in Allotment Garden Diary
4 comments on “Keeping Water Clean & Safe
  1. Irene Hamilton says:

    Thank you, the information is just what I needed.

  2. Keith Height says:

    Do the tablet’s work on a clear IBC when tap water is in it.


    • John Harrison says:

      I believe so but if you want you can contact Envii and ask

    • Envii says:

      Hi Keith

      Water Butt Klear tablets will work in a clear IBC, but due to the volume of water in an IBC, it may be more beneficial to use Pond Klear as this treats a much larger volume of water.

      As John has said though, if you want to get in touch with us we can answer any questions you might have.

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