What factors influence the effectiveness of plastic sheets in weed control?

The effectiveness of plastic sheets in weed control is heavily influenced by their thickness, weight, and the presence of additives that retard breakdown by UV light. Thicker sheets can provide a more robust barrier against weeds, preventing light penetration which is essential for weed germination. The weight of the plastic also determines how well the sheet can remain in place and resist environmental factors like wind.

Additives that slow down the degradation of the plastic due to ultraviolet (UV) light are crucial because exposure to sunlight can cause plastic to break down over time, reducing its effectiveness as a weed barrier. By incorporating such additives, the lifespan of the plastic sheets can be significantly extended, allowing them to maintain their functionality for a longer duration, thereby enhancing weed control efforts.

While the other factors like color, material type, and brand reputation can have some influence, the most direct elements that impact the practical performance in the field are those mentioned in the correct answer.