I have a "Secret Garden" in a storage room in the basement of my house. It's currently a [[Hydroponics | hydroponics]] system growing leafy greens. You can see an hourly photo of it below:
The garden uses nutrient film technique (NFT) to continuously deliver a shallow stream of nutrient solution to the plants growing in 2" ABS pipe. A submersible fountain water pump sends nutrients up 1/4" irrigation hose to each of the four pipes. The nutrients flow down the slope passed all the roots and return to the ~25 L reservoir. An air stone oxygenates the water. Two computer case fans ensure adequate [[Airflow|airflow]].
My previous system [[Helios Alpha]] could grow up to six plants. It's designed around a single 102 L plastic tote. It holds enough water to harvest lettuce once before refilling. After the initial setup, the system can be ignored for weeks.