Mercury Vapor Lights

Dennerle is not the only manufacturer of Mercury Vapour Lights for plants!
I am using a Quebec-made product, called the WonderLight, which is MV (plus
some secret ingredient to adjust the colour spectrum). The CRI is fairly high,
but the efficiency is low. I have some background on the bulbs, e-mail me
directly if you are interested.

in sunny but cold Waterloo