I would say yes. Plastic takes super long as you know to break down so no issue on this material lasting, though my only concern would be toxic residue from the plastic. So perhaps something to look up and confirm before going ahead, especially if you're growing food.
Is it safe to cover them with soil or bury them in a garden bed for drainage?
I would say yes. Plastic takes super long as you know to break down so no issue on this material lasting, though my only concern would be toxic residue from the plastic. So perhaps something to look up and confirm before going ahead, especially if you're growing food.
Doesn't it matter that they are flammable?
I know they should only be used for insulation - and depending on council requirements would probably be required to have an anti-flammable coating.