plastic bottles covering vegie seedlings

[frozzbite]

What are the benefits of putting plastic bottles over vegie seedlings.
I'd like to know the science(in laymans terms)behind this supposedly helpful trick of vegie growing.
And I also want to know if it is benificial to drill a few small holes in the bottle.

 

[atulkalaskar]

I can think of few things.

First it will create humid environment around the seedlings.
It will also trap CO2 which can be used by the plant.
It offers protection against wind and cold but you may want to be careful if your climate is hot and in such cases prolonged heat exposure with high humidity may cook your seedlings.