Why is spreading compost better for growth in plants?

Answer 1

That it provides a healthy environment conducive to optimal growth is the way in which compost is related to plant growth.

Specifically, compost can be considered the end product of a decomposition process which yields dark, fresh, nutrient-rich matter for the soil environment in which plants grow. Nutrients such as carbon and nitrogen count among the necessary ingredients for healthy soils, soil food web members, and plants. Compost provides the nutrients in such a way that they can be taken in by plants. It also represents the source of both improved air and moisture passage through and retention by soil since it contributes to how soil holds together.

Answer 2

That it works effectively as a natural fertilizer and a mulch is a reason why spreading compost is better for plant growth.

Specifically, compost can be applied above and below the ground. Below the ground it functions as a ready source of soluble nutrients whose presence aids plant growth and improves soil fertility and structure. Above the ground it may be applied as a mulch whose presence balances temperature extremes, facilitates moisture retention and obstructs weeds. As it decomposes, it will leach nutrients into the soil in beneficial ways.

Answer 3

Compost nourishes plants.

It's also a good idea to mix compost with the soil -- amending it -- each year before you plant.