The hardest part for this project is finding a water tight tub. Luckily the college I was attending had very wasteful students! I found both of these tubs for free!
The toilet valve on the right is fed by the white hose at the top of the picture. When the water level is low, the valve will drip until the float rises and seals up the valve again.
The red tray is for soil. The nylon strings wick water up from the reservoir. They extend to the bottom of the tub so as to extract every last drop of water in a drought situation.
The tube on the right of the tub is for overflow in the event the rain barrel fills up and gushes water into the greenhouse.
Some shower rings make a great rain chain for directing water into the cider jug/ vacuum hose downspout. Bent steel and pvc make as good a gutter as any.
Rain barrel from a trash barrel!
Plumber’s putty is handy!