[GekkePrutser]

Those greenhouses are the size of many football fields.. Putting tarps over them is a job that will take many days :)

But yeah shutters or something smarter (like two-state glass) should work IMO. I think you even get glass that can switch to mirror mode.

[_jal]

> like two-state glass

That would be crazy-expensive. A lot of greenhouses use poly-film, to give you an idea of the budget. Replacement cost is a large factor.

[Someone]

There is research on whether solar arrays would be a net benefit. Those cells would catch most of the sun’s light, turn it into electricity to power the LEDs that have wave lengths that are better matched to what the plants need.

A variation of that only catches the sun’s green light and uses it to power pink/red LEDs (https://www.treehugger.com/solar-technology/solar-smart-gree...)

[imtringued]

Mass produced photovoltaic is 22% efficient. LEDs tuned to the plant are 50% efficient. Net efficiency 11%. Now you need 9 times as much land to grow the same number of plants.

[DagAgren]

Plants reject a lot of the visible spectrum. The question is, can you make up for the losses in solar panels by giving plants light that they can use more efficiently?

[wastedhours]

Probably expensive and still a waste of electricity, but why not automate it like the covers over pro-tennis courts?