Frost Injuries and Protection, Secondary Bloom 339 



ous materials; as, stable manure, leaves, baled hay or 

 straw, or in fact anything that will allow of the blaze being 

 easily controlled to give rise to a dense smoke. Within 

 certain limits such means of protection is successful, but 

 when more than five or six degrees of frost occurs, the 

 smoke and the small amount of heat given off by the burn- 

 ing of the smudges does not afford sufficient protection. 

 Moreover, smudge material is difficult to secure in large 

 quantity, and the supply too often gives out at the critical 

 time. 



The failure of smudging under conditions in which we 

 would expect it to be successful can be attributed, no 

 doubt, to half-hearted work, failure to begin before the 

 danger point is reached, or lack of concerted action. Al- 

 though the fruit districts of the inter-mountain states-, iso- 

 lated valleys as they are, seem to furnish ideal areas under 

 which to demonstrate the value of smudging, it must be 

 said that after thorough trial under existing conditions 

 (isolated orchards, extremes of temperature, and the lack 

 of suitable smudge material) it does not meet the require- 

 ments of frost-fighting. In lack of other protection, how- 

 ever, the grower should not give up, for faithful smudg- 

 ing is a failure only in the case of an extreme drop in 

 temperature. 



The fires should be started before the danger point is 

 reached, and the cloud of smoke maintained until the sun 

 is well up, or until the temperature rises above the freez- 

 ing-point. The smoke screens the frozen plants from the 

 sun's rays and prevents rapid thawing out, which is as 

 detrimental as freezing. 



