There seems to be an ongoing discussion about this subject and not a final conclusion yet, I imagined maybe somebody on this forum could know better.
Low-e glazing (at least Pilkington Energy Advantage Low-e pyrolytic coating) gives a subtle blueish tint when looking at it, that means it is reflecting some of the blue light spectrum from the sun and not allowing it to enter your house or greenhouse.Plants use the PAR (Photosynthetycally active radiaton) spectrum of the sunlight, which is a little broader than the human eye visible spectrum (it includes some of the IR and UV spectrum). In other words, you can’t judge with your bare eye if the glass is allowing inside the house the light that plants need to thrive.

In my own house, my wife complains about plants not thriving enough and blames the low-e glazing. We are building a greenhouse for fruits/vegetable production and are in doubt of whether to use low-e double-plane glazing or just plain double-panes.

Any thoughts about this?

Thanks guys.

Some interesting links I found on the web (not really sure if all of this are unbiased):

http://forums2.gardenweb.com/discussions/1480695/low-e-windows-effect-on-plants
https://www.pilkington.com/resources/ats148growingplantsbehindlowe20130114nsgformat.pdf
http://www.pcsierteelt.be/hosting/pcs/pcs_site.nsf/45191b4dc69a85ccc1256c25004b9e3d/fcbcffb4eedb8a58c1257c1a0041dbeb/$FILE/Low%20E-glass%20an%20alternative%20for%20horticultural%20production.pdf