Growers
Here are the chief benefits of using compost whether you are a grower of fresh produce or pot plants, bedding or nursery stock. 

• Reduces cost - Compost improves soil quality which leads to better plants and crops that need less irrigating, that are easier to cultivate and need less fertilizing. It is difficult to put a finite cost on this benefit but growers and horticulturalists, particularly those who get their compost locally, thereby reducing transport costs, definitely notice the difference.
• Reduces the need for inorganic fertilizers - Compost is a valuable organic source of the nutrients commonly found in inorganic fertilizers. Nitrogen, phosphate, potash, magnesium and sulphur (as well as trace elements) all occur naturally in compost, in quantities that can be extremely valuable.
• Improves soil structure - It's been proven that compost improves the aggregate strength of soil. It also allows root systems to penetrate more easily, enabling them to find nutrients and water more efficiently. Adding compost improves workability, too, and makes soil less likely to compact under heavy farm machinery - meaning it can be used more frequently.
• Can increase yield - Modern plants and crops need to establish rapidly in order to thrive. To do this, they depend on very high levels of organic matter in the soil. Tests prove that adding fertilizer is no substitute for this organic matter. Compost not only provides fertilization, it is high in organic matter. 
• Raises water retention capacity - Soil rich in compost absorbs and retains water better. This means it needs less irrigation, which reduces overall consumption. 
• Reduces soil erosion - Wind and rain can erode soil, particularly when it contains low levels of organic matter. Compost can be applied generally to solve this problem, or deployed in areas of particular concern. 
• Contains valuable micro-organisms - Micro-organisms do three good things to soil. Feeding off the organic matter in compost, and teaming up with the micro-organisms already present in the soil to which they've been added, they release polysaccarids and humic sustances that help improve soil structure. They release nutrients in organic matter and make it available to plants and crops to use as food. They can suppress soil borne plant pathogens.