Fertilizing blueberries using your drip irrigation system, also referred to as "fertigation," enables you to deliver the diluted fertilizer directly to the plant roots, meaning you can use far less fertilizer. Feeding your blueberry plants through drip irrigation prevents potential injuries to the plants from over-fertilization and makes dosing your fertilizer application much more precise. Several models of automatic fertilizing systems exist that connect to your drip-irrigation faucet assembly.
Apply a water-soluble nitrogen fertilizer to your blueberries through the drip irrigation during a scheduled watering at bud break, again six weeks later and a third time six weeks after that.
Install and connect the automatic fertilizing system to your drip-irrigation faucet assembly, according to the manufacturer's instructions.
Place the automatic fertilizer tank on top of a small table or stand so that the tank is within 12 inches of the height of the faucet connector.
Fill the tank with 2 inches of water. Mix into the water a water-soluble blueberry plant fertilizer that is high in nitrogen and potassium but low in phosphorous, such as a 27-9-18 or 12-4-8 NPK (Nitrogen-Phosphorous-Potassium). Cut the regular dosage recommended on the package in half.
Open the valves that control water flow from and to the tank. Turn on the water at the faucet. Watch to ensure that the tank fills with water and begins to flow out into the drip-irrigation main line.
Adjust the water flow rate using the dial on the tank's cap. Allow the fertilizer solution to flow out of the tank until it's empty and the tank fills with clean water.
Shut off the water when the irrigation cycle is finished. Close the two valves to and from the tank, and remove the automatic fertilizer system from the faucet assembly. Rinse out the tank and assembly thoroughly, allowing it to dry before storing it.