The removal of small soil plugs from a lawn, and the introduction of air to the soil. Lawn aeration helps prevent soil compaction, which can reduce the pore space within the soil that typically holds air. Since roots need oxygen to grow, a compacted lawn can result in low nutrient uptake for grass and a physical barrier for root growth. Aerating is essential to proper lawn care, as it can help improve growth and prevent fertilizer and pesticide runoff.