Share 'bolting of crops'

Dear All, If you're like me (a sad state of affairs must be said) you may have bolting lettuces, spinach etc in your garden. I know enough to realise it is a combination of heat and daylength (actually night length). But can anyone explain where to find out, in a simple enough form, what conditions cause plants to bolt. Also how this information can be applied to choosing between spring and fal...