What’s the ideal form of frost protection?

There are a number of different individual features to consider and there are a number of separate interest groups with stakes in the method.

Interest groups:

• The Grower
  
• The Crop
  
• The Environment
  
• The Neighbours
  

The Grower:
Features that are important to the grower are things like;

• It should be cost effective to install and run.
  
• It must be reliable.
  
• It must protect the crop from frost.
  
• It should not be labour intensive.
  
• It must be safe to operate.
  

The Crop:
Features that are important to the crop are things like;

• It must not affect the normal growth / development of the plant.
  
• It should not introduce any foreign contaminants.
  
• The quality of the fruit should be unchanged.
  

The Environment:
Features that are important to the environment are things like;

• It should not deplete a natural resource.
  
• It should not make any physical impact other than on the crop.
  
• It should not introduce any pollutant to the environment.
  

The Neighbour:
Features that are important to the neighbour are things like;

• Its operation mustn’t affect their health.
  
• Its operation shouldn’t degrade their property values.
  
• It shouldn’t degrade their enjoyment of their own property.
  

Now I am sure that there are other features and possibly other interest groups in the wider scheme of things, but this is a fair start.
Of course the list provides an opportunity to evaluate different methods on their appropriateness, but because each interest group has a different agenda, there will always be conflicting drivers for what constitutes an ideal method.
That said, there is merit in evaluating the methods and comparing them, simply because it highlights the disparity between the different groups, promotes debate and perhaps arrives at resolutions / compromises.