Plastic that looks like plastic adds its own surreal touch to any scene. I use sheets of food wrap to cover plugsheets trays until the seedlings push up above the surface. The plastic holds in heat and keeps the seedling mix moist, both of which the seeds definitely like. As soon as the seedlings emerge, off comes the plastic. Time to let the air flow. I reuse new sheets of wrap for a whole season. With use, they lose their clinginess and are that much easier to handle. The little things add up!