1. practicalaction.org/floatinggardenchallenge
Briefly explain that this is a challenge put together by an organisation called Practical Action; a charity who
work with poor people all over the world, using technology to help them lift themselves out of poverty.
practicalaction.org/floatinggardenchallenge

2. What problems are caused by climate change?
Look at the photographs given to you by your teacher
What do you see in the photographs?
Where do you think it is happening?
What are the main problems for people in the photos?
Sort your pictures into two groups. You decide how…
Divide students into groups, give each group a set of pictures and encourage them to discuss. Climate
change is making both flooding and drought more of a problem throughout the world.

3. Flooding and drought
You may have divided your pictures into different groups:
Flooding and drought, or
Effecting the UK and other countries.
Either way is correct 
Flooding and drought are caused by changing weather patterns and are having devastating impacts in the UK and around the world.
Some of the students will have divided pictures into groups – drought and flooding. Discuss how these
extremes are both being made worse as a result of climate change.

4. Impacts of changing climates
Practical Action works with people living in Bangladesh who experience some of the worst effects of climate change.
Floods affect over 1 million people in Bangladesh and last longer each year.
Many families lose their crops and the vegetables they were growing to feed their families.
Explain the challenge: you may like to look at the geography of Bangladesh and get students to think about
why Bangladesh is more prone to flooding than other countries. It is important that they understand flooding
has always been a problem but climate change is making it worse.

5. Your Challenge
The problem: The land where crops used to grow now gets regularly flooded. The challenge: Design and build a model of a structure that people could grow their crops on even when it floods. Present your findings: You will be asked to present your work and model to the rest of your class.
There are teacher’s notes to support you to prepare and run the challenge, available on the website.
For secondary age students, if you would like your students to take part in the CREST Discovery Award scheme, go to to find out more.
For more information visit britishscienceassociation.org/crest or
For primary age students you could adapt for a CREST Superstars award by simplifying to designing one
floating garden then building it. You could also give students a set of materials to choose from with two or
three variables e.g. buoyancy.

6. What should you consider?
For crops to grow on flooded land they could be planted on a raft like structure, or ‘floating garden’.
The top of your model should be fairly flat so you could grow your own crops on top of it.
Your model must not be wider or longer than 23 x 30 cm, so you can test it in a washing up bowl.
The winning group will be the one whose raft holds the most weight before it sinks.

7. A solution?
Practical Action works with people to develop sustainable technologies that enable people to have a decent quality of life. In Bangladesh, Practical Action worked with farmers to develop floating gardens, a technology that uses locally available materials to grow vegetables even during the floods.
For further information on the technical construction of a floating garden and its use in Bangladesh
a technical brief is available at practicalaction.org/floating-gardens.

8. How are floating gardens made?
The rafts are approximately 8 metres long and 1 metre wide.
They are made up of layers of water hyacinth, bamboo, cow dung and compost.
The crops are then grown on
the top layer of soil.
The garden floats to the top of the water during the rainy season and returns to ground level when the floods subside.
For further information on the technical construction of a floating garden and its use in Bangladesh
a technical brief is available at practicalaction.org/floating-gardens.

9. Making a difference?
Many families are benefiting from their floating gardens as they are able to grow vegetables such as okra and leafy vegetables throughout the year.
Watch the video from Bangladesh.
What do you think happens to the ‘raft’ once the crops have been harvested?
Do you think floating gardens would work elsewhere in the world?
During harvesting, the rafts can be accessed by foot or by raft or boat if the water is very deep. A more
detailed case study of Rahima and how her family has benefited from their floating garden is available.
Floating gardens are an excellent example of sustainable farming. The materials used are locally available.
The old rafts are used as fertilizer for the next crop. Go to practicalaction.org/floating-gardens to find out
more. We have also encouraged farmers to keep ducks instead of goats for one simple reason – ducks float!!
practicalaction.org/floating-gardens

10. What can you do next?
Grow some food on your floating garden! Place damp blotting paper and a bit of soil on top of your garden. Then sprinkle a few cress or lettuce seeds on top and watch your garden grow.
Scale Up – develop a real floating garden for use on a pond.
There are a number of other activities your students can get involved in following the challenge. They are freely
available at practicalaction.org/stem

11. Taking your ideas further…
If you’ve enjoyed taking part in the Floating Garden challenge you might want to try some of Practical Action’s other STEM challenges:
Stop the Spread
Design For A Better World
Beat the Flood
Squashed Tomato challenge
practicalaction.org/stem
There are a number of activities your students can get involved in following the challenge. They are freely
available at practicalaction.org/stem
There are a number of activities your students can get involved in following the challenge.
If you have achieved your CREST Discovery Award through the Floating Garden challenge you can go on to work towards your CREST Bronze Award crestawards.org

12. Thank you for taking part in the challenge
Let us know how you got on with your floating garden challenge by
ing your photos to
We’ll add them to our website: practicalaction.org/schools