What practice helps avoid weed contamination when using compost-based topdressing?

• A. Use well-composted material and apply in moderate amounts.
• B. Apply raw compost in thick layers.
• C. Use only sand with compost.
• D. Do not apply during renovation.

Answer: (A)

The main idea is that weed contamination from compost topdressing is minimized when you use material that has fully matured and you apply it in moderate amounts. Well-composted material has undergone enough heat and microbial activity to kill many weed seeds and pathogens, giving you a stable, well-integrated topdressing rather than a seed source. Applying a moderate amount helps level the surface and improve turf growth without creating a thick layer that can smother the existing grass or create conditions that encourage weeds to germinate once the layer breaks down. By contrast, raw or immature compost can still harbor viable weed seeds and pathogens, thick layers of material can trap moisture and reduce oxygen, and other options don’t directly address the weed-seed issue.