Miracle-Gro makes a "Garden Feeder" that attaches to the end of a hose. You put water soluble fertilizer into the "Garden Feeder" reservoir and it mixes with water from the hose, which then sprays out onto your plants. Has anyone tried using one of these with a drip irrigation system? My thought is that you could remove the "showerhead" from the "Garden Feeder" and attach the reservoir in line with the source end of the drip irrigation hose. Then, when you wanted to feed your plants, you could do it by adding fertilizer to the reservoir instead of mixing it and manually pouring it on the plants.