Power raking untangles dead grass from the living plants around it, a process that can bruise and even kill the live plants if you are not careful, which is why you should hire a professional to do this for you.
Power raking should be done either in the spring or fall, when grass is growing vigorously but heat stress is not a problem. This will give plants a chance to recover before they become dormant in winter or midsummer. Power raking should be done when the soil is dry but the grass is not brittle. Wet soil will not hold live grass plants well, and more will get pulled out or torn during the raking than when the soil is drier.
Lawn aeration is done through the use of a special tool designed to aerate soil in which lawn grasses grow. Aeration improves soil drainage and encourages worms, mirofauna and micoflora, which require oxygen. Lawn areation helps in two important ways, controlling lawn thatch and reducing soil compaction. Lawn thatch is a layer of dead organic tissue that deprives the lawn of much-needed oxygen. Soil compaction makes it difficult for grass to root and it disturbs natural rainwater irrigation.