Its very easy. It will run 24/7 but will need a little maintanance.
You will need a one gallon milk jug.
Fill it 3/4 way with warm NOT HOT OR COLD water.
2 cups pure sugar
1 pack dry yeast(anykind of yeast that still works)
add the sugar and shake to mix it up.
Then add yeast to mix in and skake for a few seconds.
set the milk jusg above your plants
the yeast will produce CO2 and it will overflow the milk jug and shower down on your plants.
About every 3 days you will need to take out 1/2 the water and replace it and add one cup of sugar.
NO NEED TO REPLACE THE YEAST. They replace themselves.
Its that easy.
*Note* It may smell al little so an air freshner may be needes but not always.