Why do cacti require so much less water than other plants?

The answer to both your questions is "yes." They are models of efficiency. Over many eons they adapted their structures to the requirements of living in areas of diminished rainfall. read more

The “how” includes several strategies, such as pleated ribs that expand to store water; waxy skin to keep moisture in; opening their pores at night to keep water from evaporating during the hot day; and broad, shallow root systems to collect as much rainwater as possible. read more

Although they’re far more resilient than most other types of plants, cacti still need a good balance of fertilizers to help them thrive throughout their growing season. For most varieties of cacti, this is going to be in the warmer, more humid summer months. read more

Like all living things, cacti need water to survive. Given the areas where they live, though, water is often scarce. To compensate, cacti have developed special abilities that allow them to conserve the water they do receive and make it last a long time. For example, the prickly spines of cacti are actually highly-modified leaves. read more