What can protect plants from cold except film?

For protecting plants from cold may be used different covers - mats, paper caps, etc.
Good plant protection caps are made of translucent waterproof paper. Paper caps are doing as:
paper is cut into squares with sides equal to 50cm, angles are cut little, then fold the paper so as to form eight segments extending from the center of the square. Then two any segments are folded together and added to the third. For the strength of folded paper can fasten with pin. But cap keeps its shape pretty good without this).
In order caps not to carry away by the wind, their edges are covered with soil.   
Cucumber, tomato, eggplant, pepper plants are covered with paper caps after planting in open ground. If weather is warm, should not to do it.

To protect plants also can be used pottery or other pots without a bottom. The diameter of the pot 16-17cm. Square-shaped pieces of glass, cut from broken glass are used to secure the top of pottery.
To protect plants at night, you can use put together from boards gutter.  The using the boxes and other devices are recommended also for protecting plants.