I thought I'd enlighten myself on what a Fresnel lens is - and what it could
have to do with agriculture. Well, here is the first url that came up, but I
am still in the dark, thanks!,
http://lighthousegetaway.com/lights/fresnel.html
In my experience, I have found common green plastic tarps to pass enough
light to keep sod growing, and black plastic to take considerably longer
than clear to kill quack grass. Del
>Good idea about the fresnel lens. I know that people use propane
>torches (eg Red Dragon) to control weeds without herbicides. I can see
>the fresnel lens accomplishing the same with free solar energy. As a
>kid, I used to melt lead with my giant lens. To anyone going to
>experiment with this... use the same caution you would with weed torches
>and wear extra dark glasses.
>-Mark Lee, Seattle