SMUDGING TO PREVENT FROST 



W. J. GREEN 



The protection of fruit and vegetable plants against frost has 

 been widely practiced, especially in the coast regions of the extreme 

 west. It has not been so generally practiced in the eastern states 

 but there are few localities where the plan has not been tried to 

 some extent. At one time smudging was looked upon by many as 

 one of the essential horticultural operations but belief in it as a 

 practical and necessary item of orchard practice is less firmly held 

 than formerly. 



The main reason for the change in opinion is because of the 

 cost of such work and uncertainty as to results. The temperature 

 can be raised in this manner but it often happens that when one has 

 spent considerable time and money in smudging against a looked-f or 

 frost the temperature does not fall below the danger line. This 

 makes smudging of very doubtful utility, even though it is some- 

 times the means of saving a valuable crop. 



Wood and coal are not satisfactory materials for smudging as 

 they require too much labor and respond too slowly when it is 

 desired to raise the temperature quickly. Crude petroleum, burned 

 in suitable heaters, will raise the temperature quickly and hold it 

 for a considerable time, but one cannot be sure that a frost will 

 occur even though it is predicted by the officials of the weather 

 bureau. 



Just when to begin lighting the heaters can be determined only 

 approximately even though a constant watch is kept through the 

 night. Heating in winter to protect fruit buds is even less prac- 

 ticable than heating to protect blossoms in spray time. 



Mulched strawberry beds may be set on fire unless a consider- 

 able space around each fire pot is left uncovered. There is danger, 

 also, of setting fire to grass and straw with heaters in mulched 

 orchards. 



While it is true that there are considerable losses by burning 

 oil in orchards when not needed it may be due, in some cases, to over 

 zealous orchardists who are anxious to try something new. The 

 fact should not be overlooked, however, that orchard heating is an 

 expensive operation even when no unnecessary work is done. 



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