Using milk to water plants will help them grow better.
 

Milk and plants

Most of the ingredients found in milk are not required by plants. Fat, lactose and carbohydrates found in milk are not essential to plants. Proteins in milk are rich in nitrogen but they are not in a form that plants can synthesize. However, milk contains calcium and some minerals that may help plants grow better.

Plants get most of their nutrition directly from soil. Water is very important for plants to grow and remain healthy. During photosynthesis, plants use water and carbon dioxide to produce sugar and oxygen. Water is also used to transport minerals absorbed from the soil to other parts of the plant. Plants also need water to prevent dehydration and for transpiration.
 

The hypothesis that using milk to water plants will help them grow better is disproved.

Watering plants with milk may provide additional nutrients for the soil, but the transpiration of water from the soil may cause the concentration of milk solutes to increase and make it hypertonic. This will make the plant wilt because they cannot absorb water from the soil. Milk will also cause bacteria growth and attract insects that can harm the plant and its roots. Plants watered with milk usually wilt and die after a few days or weeks.
 

Try to repeat the science fair project using other types of plants like radish, chili or sunflower.

Try using 4 or more pots in this experiment – eg. 2 or 3 pots of seeds watered with water, 2 or 3 pots watered with milk – for more accurate results.

The experiment can also be repeated using different concentrations of milk mixed with water.