By topping from summer through to autumn you will encourage a better quality grass to grow. By cutting the weeds before they seed you will lessen the chance of them returning. It's best for grass to grow to 4", but not more than 6" before grazing.
The idea of harrowing is to remove dead grass and moss, etc., allowing the light and air to the base of the grass. This encourages growth and strengthens existing grass.
Crushing the grass crowns encourages the spreading of the plant, thereby maximising the spring growth. When combinded with harrowing, it will significantly help level areas.
