open ended self venting low tunnels

I am thinking of building low tunnels out of PVC pipe to get our community farm off to a running start. We already have a high tunnel with automatic venting, but we have too many early crops for them all to fit.

If I covered the hoops, including the ends, with row cover, and then covered the hoops, not including the ends, with builder's plastic, would the tunnels get enough ventilation out of the ends? Automatic venting is prohibitivly expensive, and we can't be sure that somebody would be there every morning and evening to cover and uncover them.

The tunnels would be about 10 feet long. This is in Colorado in March, so the sun is hot when it is around, but there are quite a few cloudy days in March.