Scientific explanation of grey water's affects on plant growth. Quick and easy to follow.
Step 1: Background Information:
Today we are faced with two significant issues in society: the overuse of the finite supply of water in the world and the cost of living. Many households save both water and money by recycling grey water on their garden. This means watering ones garden with old dishwashing water, shower water or laundry water.
However, does the soapy water negatively affect the plant’s growth and development. Some sources say that “plants have been scientifically proven to grow better with grey water”  . However some other sources suggest that it could harm the plant and that normal clean water should also be used.
“the potential harm is less to the plants than to the soil, with its complex bacterial and fungal make-up. Recycled soapy water (‘grey’ water) is perfectly usable for plants, but I would not use it exclusively. Rotate it with ‘clean’ water on an alternate basis and, as with all watering, direct it at the roots rather than the foliage.” 
Step 2: Aim
To find out whether using a solution of detergent and water to water plants will negatively effect the growth of that plant.
Step 3: Hypothesis
The more detergent used whilst watering the beans, the less these beans will grow. All the beans will show some growth.
Step 4: Equipment
- 9 Sauces
- 18 Lima Beans
- 72 cotton wool disks
- 20mL Syringe
- Cold Water
- Washing Detergent