Bring a pot of 3-percent hydrogen peroxide to 140 degrees Fahrenheit on the stove. Place alfalfa seeds in the strainer, and lower the strainer into the hydrogen peroxide. Allow the seeds to cook for five minutes to kill any pathogens.
Rinse the alfalfa seeds for one minute under running water. Place the seeds in a container and cover it with about 1 to 2 inches of water. Skim any floating items from the surface of the water.
Disinfect your canning jar with a mixture of ¾ cup of bleach to 1 gallon of water. Allow the jar to soak for five minutes, and then rinse it off with clean water.
Place 2 tablespoons of alfalfa seeds in the jar and fill the jar with cold water. Set the cheesecloth over the top of the jar and screw the canning lid over it to hold the cloth in place. Allow the seeds to soak for about eight to 12 hours.
Drain the water and rinse the seeds with fresh water. Drain the seeds again. Swish the seeds around in the jar so they are sticking to the sides, and place the jar in a dark location with the jar tilted at an angle.
Rinse the seeds twice a day until the alfalfa sprouts are 1 inch long.
Place the jar of sprouts in a sunny window for two to three hours so the sprouts turn green. Rinse the sprouts in a bowl of clean water, and remove anything that floats to the top. Store the sprouts in the refrigerator.