A green leaf is a small solar-powered workshop. In photosynthesis, it uses light energy to make sugars from carbon dioxide and water, releasing oxygen. The plant can use those sugars, store them or turn them into other materials.

Think of photosynthesis as income. For the ordinary green garden plants in this lesson, it supplies the ongoing energy and carbon needed for growth. Seeds and established plants can also draw on reserves; they do not start every morning with an empty account.

This helps explain why light matters, but a garden is not a fixed price list. There is no universal number of sun hours that buys leaves, flowers or fruit. Different species and growing conditions change what the plant can do.