We visited a greenhouse in Anchorage that grows tomato plants...thousands of tomato plants! But look past Doug in each picture and look out the windows. What you see is snow, snow, snow. You can see how deep it is.
Hot air is forced through these plastic tubes to tubes that are lying on the ground beside the plant rows.
Once the tubes on the ground are filled with hot air, a hole is punched beside each plant so that hot air blows directly on each plant.