Subject: Why does my wires light up a lightbulb with a battery and not with a lemon

I am doing the science project Food Batteries.I've tried everything.The 
only thing that lights up my tiny lightbulb is a battery.I've tried having 
bigger electrodes, having different fruits and vegetables, and I've tried 
different sizes of fruits, basically everything.Nothing has lit up the 
bulb.I really need some answers for this, if my parents and I can't figure 
out a way to do this simple project then you need to take it out of your 
archives

Re: Why does my wires light up a lightbulb with a battery and not with a lemon