Garduino tiny board was developed for the purpose of Valentina’s Karga workshop :
“Gaduino – alternative ways of living and pracitces of autonomy”.
It consists of an ATtiny85 chip which you can program using Arduino code, a 12V solenoid valve and 2 nails for sensing the soil moisture.
You can program the Garduino chip with an arduino compatible board by many ways.
First building the circuit of the above schematic that works as a shield for arduino. Schematic Board
Another way is to remove the ATtiny85 chip an place it to a breadboard following the connection above:
Finally you can connect the Garduino tiny board directly to an arduino following the above diagram: