Q: Why do we seed at the rate we do?
A:We know through experience and research that crowded plants are less vigorous than well spaced ones. This is true for vegetables, perennials, trees, shrubs and grasses. If we plant new shrubs close enough to look full they will become stressed as they mature due to competition. The same is true for grass.
As each seed germinates it starts as only one very thin blade but as the plant matures it puts out many more blades that are each much thicker. The purpose of these blades is only to intercept sunlight to make food for the plant. If we plant too thickly for a full look at the beginning of the life of the grass there won’t be enough room for each plant to spread out and intercept enough light to grow well. That means stressed plants and that means prime targets for infection.
We live in a climate that is already great for fungal and bacterial disease development and a stressed plant is an unnecessary invitation to attack. We seed lighter than most people are used to and if needed come back and add more seed. That makes more sense to us than seeding too heavy and coming back and adding fungicides.