Competition in plants

Light

All plants and algae need light to photosynthesise. Plants compete for light by growing quickly to reach it and often shade other plants with their leaves. When an old tree in a forest dies and falls to the ground, there is a race to fill in the gap in the canopy. It doesn't look like a race to us because it happens slowly.

Water from the soil

Water is a reactant in photosynthesis and it is essential that plants have a regular supply of water for the process to occur. Some fully grown trees, like the oak tree, lose a staggering 150 litres of water per day, which is used to transport materials through the plant to the leaves. Some plants have roots that are shallow but extend a long way from the tree to maximise the update of water after rainfall. Others have roots that are deep to find stores of underground water.

Minerals from the soil

Plants require minerals for healthy growth. These include nitrates and magnesium. Without sufficient minerals plants suffer deficiency diseases because they cannot grow healthily. Plants that grow in soils with few minerals, such as bogs, have evolved different ways of accessing minerals. Some, like the Venus flytrap and pitcher plants, have evolved to be carnivorous and consume insects, enabling them to grow more successfully than their competitors on mineral-poor soil.

Space

Plants also require space for healthy growth. This means their leaves are not shaded which maximises photosynthesis. Some gardeners have experimented by planting vegetables very close together. This results in much smaller vegetables being produced.