Which amendment improves moisture retention and aeration in soil?

• A. Vermiculite
• B. Perlite
• C. Lime
• D. Gypsum

Answer: (A)

Moisture retention and aeration in soil depend on amendments that hold water while keeping enough air spaces for roots to breathe. Vermiculite fits this well because it is a hydrated mineral that expands and traps a significant amount of water in its layered structure. That water is released to plant roots as needed, helping keep the root zone consistently moist without becoming waterlogged. At the same time, its light, flaky particles create porous pockets that improve soil aeration and reduce compaction, which helps roots access oxygen.

Perlite also improves aeration but doesn’t hold as much water, so it’s more about drainage and airy texture than moisture retention. Lime raises soil pH and adds calcium, which changes chemical conditions rather than water holding. Gypsum improves soil structure and supplies calcium and sulfur but doesn’t notably boost moisture retention. So, vermiculite is the best choice for enhancing both moisture retention and aeration.