"Other methods include leaving a jar in the sun for several days, then adding a teaspoon of dried yeast or milk to get the culture to bloom. A third method involves placing fresh grass clippings in the jar with water and allowing the mixture to ferment in the sun."
"Infusoria feed on bacteria, so to get a batch going you will need to set up a culture of decomposing organic matter to feed the bacteria. This is best done in a jar. I recommend using either a handful of grass or a 1 cm piece of potato in 500 ml of water."
All I do is put some Java Moss from an established tank along with some of the tank water, in a beanie container, add a couple drops of Liquifry #1 and put it in the windowsill...Infosoria galore in no time.