[Ag-eq] gardening

[Jewel]

Is the soft styrene that is used for meat trays etc poisonous for the soil?
I believe that they are a no-no for the recycling bin, but if that material is safe, could it be cut 
up into little pieces and mixed into the soil in winter.  I wondered if it would help to keep the 
soil warm so that vegetables would continue to grow, and that  would also apply to the foam styrene 
that you find in cartons to prevent the contents from being tossed around while in transit.

          Jewel