Flooding

Flooding is an important part of cranberry management. In the spring we flood to protect the vine from cold weather. Once it warms up the flood is withdrawn and the vine can begin growing. We install an irrigation system at this point. When we get cold weather later in the spring, we run the irrigation system to protect the plant from frost.

The vine is hardy to about 20F when it is dormant, but as soon as it starts to grow the tolerance is about 29 1/2F. The irrigation system spreads water on the vine. The water has some latent heat which warms up the vine. Once it has given up most of its heat and freezes it gives up more heat (the change of state liquid to solid) to the vine. As long as you keep irrigating, the vine will now be damaged. Needless to say... cranberry farmers always watch the weather and get poor sleep in springtime.