Want fresh lettuce without the fuss? Skip the soil and learn how to grow it hydroponically on your countertop or windowsill.

In general, the green of spring leaves is fresher and lighter than the ... or how well plants are exchanging nutrients, water, and gases like carbon dioxide and oxygen with the surrounding ...

The process chemically converts carbon dioxide (CO2) and water into food (sugars) and oxygen. The chemical reaction often relies on a pigment called chlorophyll, which gives plants their green color.