Deluxe Fertilizer

Greatly improves soil quality, increasing your chance to grow quality crops. Mix into tilled soil.
Overview
Deluxe Fertilizer is a fertilizer that increases the chance that a crop will grow in higher quality. It can be placed on tilled soil before or after planting a seed, and it can also be applied at any stage of crop growth. When used, it gives crops a chance to be harvested at iridium quality, and it is the only fertilizer that allows iridium quality crops to be grown.
The fertilizer affects only the crop’s normal harvest. Any extra crops produced at harvest, such as from Coffee Beans, Blueberries, or 
Deluxe Fertilizer is not used in any bundles or quests. It can be used in the spool of the 
Official description
Greatly improves soil quality, increasing your chance to grow quality crops. Mix into tilled soil.