[TigersEye]

So the glass panels of greenhouses will heat up from solar infrared and conduct energy in both directions.

That is true of the properties of glass but the main source of heating within a greenhouse comes from infrared light that passes through the glass and hits the solid objects below like floor, walls and the plants themselves. Those solid objects then release that energy through conduction to the gases within the greenhouse passing in direct contact over them.

[justa-hairyape]

The infrared does not significantly penetrate the glass. The glass on a green house has to be of a significant thickness to withstand wind, hail, etc.. In fact, infrared only penetrates a few inches into water. Gets primarily absorbed. The solar energy that heats the interior of the green house is visible light. An experiment was done that painted an inside of a clear glass green house white. Did not significantly heat. Basically, visible light gets absorbed by colored surfaces inside the greenhouse, the surfaces warm and conduct heat to the interior atmospheric (green planet) gases which are trapped by the glass.

[palmer]

Major gases like nitrogen and oxygen, then, do not just radiate heat to the earth below, but the total of this radiation vastly exceeds what minor players like carbon dioxide and water vapor contribute

This is false. The CO2 molecule is much more likely to throw off the IR photon before it bumps into an N2 or O2 molecule to heat it. The N2 and O2 blackbody radiation is very small compared to the returned radiation from the GH gases.