Bottle / Tub  Gardens  – Self watering systems (reservoir)

Overview: Plants in traditional pots lose a great deal of water through the bottom of the pot as well as through evaporation from the top of the soil. There are designs which allow a water reservoir at the bottom of the container that the roots can access either by using a wick that transfers water from the reservoir to the roots or  by having a separate section for the water

Task: You are to produce the most water efficient method for growing plants possible using plastic bottles, bags or containers.

Equipment Provided: Plastic Bottles, plastic bags, plastic containers, compost/soil measuring cylinder/bottle with gradations. seeds/plants. Paper/cloth/socks etc to act as a wick

Health and Safety: You must carry out your own risk assessment (Rubbish Science accept no liability)  Note: Take care when cutting and wash hands after handling rubbish and compost

Things you might need to know / Questions you might ask:

  • How much water do plants need?
  • Where is water lost when growing plants in a conventional pot?
  • What happens to a plant if the roots get completely waterlogged?
  • How can you get paper or cloth to act as a wick?
  • How might you reduce water loss by evaporation?
  • Why might putting a hole a few centimetres above the base be better than in the base itself?

Prototyping: Try to answer the questions above using small scale experiments

Modifications:How might you modify your designs based on what your preliminary results look like? What have others done and what can you learn from them?

Prediction: What do you think will happen and why?

Do it: Create a table of results or some way of comparing the amount of water used

What happened?: Was your garden effective?

Tell Someone: Explain what you did and why you felt your plant growing was effective. Listen to others do they have any good ideas?

What did you learn? What do you know now that you didn’t know before you started this investigation?

Extension/Modify/Do it again: How could you extend this to produce a commercial plant growing business

Possible Models- How can you optimise the design?

  Note: This activity is ideal to do as a CREST Award