Home | Acids, Bases and Neutral Substances | What is pH? | Plants and the Effects of pH | My Experiment | Results and Photos Trial 1 | Results and Photos Trial 2 | Discussion, Conclusion and more | Science Experiment Ideas | Links Page
* * * Plants and pH * * *
Plants and the Effects of pH

Plants can be affected by many factors, for example: temperature, sunlight, deforestation and much more. However many people don't realise that acids, bases and their pH can have an effect on plants. This can be, for example from the soil, the rain or maybe from the substance the plant is being watered with.

Soil pH
The pH of soil is important for the growth of plants. Some plants grow better in acidic soils and some prefer alkaline soils. The effect of soil pH is great on the solubility of minerals or nutrients. Fourteen of the seventeen essential plant nutrients come from the soil solution. Most minerals and nutrients are more soluble or available in acid soils than in neutral or alkaline soils.
The pH of soil can be tested using soil pH test kits. If the soil is too acidic, basic substances can be added, for example powdered limestone. If the soil is too alkaline, acidic substances, acidic substances can be added, for example manure.


Acid Rain
In Northern Europe and North America millions of trees have died due to acid rain. The acid reaches into the roots and leaves of the trees and kills them. Some lakes are so acidic that all the fish and other marine life have died. Tiny water plants have also been killed off. If trees are not killed by acid rain they are affected and lose a lot of their leaves.
Acid rain is defined as rain that is more acidic than rain water. Normal rain water is usually slightly acidic because the carbon dioxide in the air mixes with the water to form carbonic acid. However gases from factories and motor vehicles make rain much more acidic than usual. These gases combine with water in the air to form acids such as sulfur dioxide and sulfur trioxide. These acids then attack the environment.
Plants and animals are not the only things that are effected by acid rain. Buildings can also be effected. The acids speed the rusting of metal buildings and stone buildings. Metal pipes also rust must quicker in areas where there is acid rain.
Most acid rain has a pH of 4.5-5.5. However in the USA acid rain as acidic as vinegar (pH 3) and lemon juice (pH 4) has been recorded. 

How Acid Rain is Formed

Water pH
Plants can be effected greatly by the water or substance being used to water it. The pH of the substance will effect the way the plant grows. This was the basis of my experiment. Although the plants were the same type and height they each grew very differently because of the substance and its pH that i was using to water each plant. Neutral substances especially water are the best for plant growth. A substance very acidic would eat away the plant and a substance very alkaline would toxicate it.

My experiment involved water pH

Intel Young Scientist 2004