I have students that run the same experiment and it has worked very well. We use the white-seeded lettuce variety 'Tango' ordered from Johnny's Selected Seeds. Seed should be kept dry while setting up the experiment and so hydration of the filter paper must be done carefully and quickly in a dimly lit area. Once moistened, the seed coat will begin receiving red/far-red signals. Germination should be checked every 24 hrs or sooner, after 2 or 3 days all seed will germinate regardless of treatment. Heat should not be necessary, but a controlled temperature environment for ALL treatments is desirable. When applying the Far-red treatment, a lower wattage incandescent bulb should be used (i.e. 40-60W maximum) and shown through the far-red filter. Red light should be applied with a cool fluorescent bulb shown through a red filter. This experiment has consistently worked very well for us adhering to these practices, good luck!
University of New Hampshire
Department of Biology