A chemical substance used mainly for enriching soil for farming, but in-game is used mostly for creating explosives at the Chemistry station.
With the addition of the Contraptions Workshop add-on, it is also used to craft ammo.
Fertilizer can be found all around the Commonwealth.
For sale at Diamond City Surplus.
Connie Abernathy sells two shipment of 25.
Daniel Finch sells a shipment of 25.
Supervisor Greene sells two shipment of 25.
If the player has a brahmin in their settlement, such as the one at Abernathy farm or purchasing one from Kelly, then fertilizer will be gathered at a rate of one per day and added to the workbench similar to excess purified water and scrap collected by settlers. If the player places a brahmin feed trough in a settlement, settlers will bring at least one brahmin. With the Wasteland Workshop DLC the Sole Survivor can build brahmin cages to capture brahmins.
By purchasing or producing fertilizer with brahmins in settlements, the player can produce Jet for a profit.