Inline fertilizers allow you to place fertilizer inside a container and distribute it automatically through a sprinkler or hose. Commercial inline sprinklers contain a tank, a suction tube, and an inlet and outlet for pipes. It's possible to make your own inline distributor using an old plant-food distributor and a few plumbing fittings. Reconfiguring the plant-food dispenser mimics the commercial fertilizer dispenser for a fraction of the cost, while saving save time and money maintaining your lawn or garden.
Locate the sprinkler irrigation control box outside the house. Pull up on the colored lid exposing the valves.
Decide which zone to attach the fertilizer. For example, if zone one on your timer controls the front lawn, then attaching the fertilizer to that zone valve provides fertilizer to the front lawn.
Remove the supply pipe that's connected to the chosen zone valve by unscrewing it with an adjustable wrench.
Screw the supply line nut that you just removed into the threaded outlet side of the plant food distributor. The outlet is marked on the container.
Screw a male-to-male PVC adapter into the plant food distributor’s other end. Tighten it with the wrench.
Screw the other end of the adapter into the port on the sprinkler valve. You have now completed the connection among the valve, the fertilizer and the sprinkler supply pipe.
Unscrew the plant food distributor’s bottom and fill the container with a high-quality liquid fertilizer. Do not use dry fertilizer, as it clogs the system.
Turn the sprinkler timer to the "on" position and test the connection. Fertilizer begins flowing into the sprinkler system for the installed zone.