Mulches are used to achieve which effect?

• A. Smother new weed seedlings by keeping out light
• B. Increase soil salinity
• C. Attract pests
• D. Require frequent replacement of mulch

Answer: (A)

Mulches mainly work by forming a barrier that blocks light from reaching the soil surface. When weed seeds are shaded and light is limited, many of them don’t germinate or quickly die, so weed growth is suppressed. This light-blocking effect is the key reason mulches are used in beds. Along with weed suppression, mulch helps conserve soil moisture and moderate soil temperatures, which supports healthy plant growth. The other options don’t fit the main purpose: mulches don’t intend to increase soil salinity, they aren’t used to attract pests, and while some organic mulches break down over time and may need replenishment, that isn’t the primary reason for using mulch.