72 POPULAR FRUIT GROWING. 



may also be laid on the ground and successfully carried through 

 the winter when covered with corn stalks. 



(b) By smudges which make a cloud of smoke over the 

 land and thus prevent evaporation. This is effective when 

 there is sufficient wind to spread the smoke. The material used 

 for this purpose is wet straw, tar, resin, etc., or a combination 

 of such material. It may be carried about the orchard on a stone 

 boat or the smudges may be located in various places. 



(c) By heating the air directly by means of fires, as Is 

 done in parts of Florida where wood is piled ready to be set 

 on fire whenever frost threatens. 



(d) By cultivating the land; moist soil is exposed, which 

 furnishes considerable protection by the evaporation of the mois- 

 ture from the freshly expos-ed soil. 



(e) By spraying the plants; the air is brought near to dew 

 point and also warmed. In order to make this effective the 

 spraying must be repeated during the night when frost is ex- 

 pected. 



(f) By irrigating the land: the air is brought near to dew 

 point and it is also warmed. This is frequently resorted to 

 in the case of cranberries. 



(g) By covering with tents, as practiced in Florida and 

 other places and even by using stoves in tents. 



(h) Covering the flowers with straw mulch at night is 

 practicable in the case of strawberries. Where the mulch is 

 kept between the rows to protect the fruit from dirt, it may be 

 thrown over the plants when frost threatens the flowers. If 

 the weather continues cold, it may remain on the plants for a 

 few days without injury, otherwise it should be promptly re- 

 moved. 



Protection against frost. In the Yearbook of the United 

 States Department of Agriculture for 1907, G. H. Powell has the 

 following to say in regard to frost protection in California, which 

 is of very general application: 



"Theie are few districts in the citrus belt of California that 

 may not be visited by frost in December, January, or February. 

 The prevention of injury by frost may be influenced to a large 

 extent by the location of groves on lands over which there is 

 a sufficient air drainage. The new groves established during 



