You could have a barrel of nutes/water, put a grommet in the bottom side for a 3/4" barbed fitting. Insert a straight barbed fitting through the grommet. Using 3/4" hose connect a submersible pond pump and have it in the bottom of the barrel. Connect a garden hose to the outside of the barbed fitting and connect a watering wand to the end of the hose. Plug in the pump and water. Unplug the pump when done.