Polystyrene ok for lettuce growing?

got these trays that were already in my greenhouse....do u think theyd br ok for growing cos lettuce if i put some drainage holes in?

 

Expanded polystyrene is inert (puffed up with Nitrogen).

Not to be confused with Poly Styrene who was far from being inert

 

They would be ok for starting lettuce off, ready to plant out later.

 

I would think so. Do you know what were they used for?

 

Yep

I keep mice in the one in my greenhouse. Think they like the warmth and watching the world turn dayglo

 

Transporting chilled/frozen stuff (including fishing bait to tackle shops is one I know of). Those boxes come with lids.

 

Well the chap was a very keen gardeners so i assume he was using them for plants.

Are they not big enough for a cos lettuce to grow in permanently?

 

I'd say not, scaling by the petals lying on the ground.