128 PRINCIPLES OF PLANT CULTURE 



large plantations in this manner. Considerable plantings 

 of the strawberry have been successfully protected from 

 frost by covering the rows in the evening with straw or 

 marsh hay, and where these materials are convenient, 

 the work may often be cheaply and quickly performed. 



Sometimes small plants standing in well-separated 

 rows, such as potatoes, may be saved from frost injury by 

 so running a plow between the rows that the plants are 

 covered. The soil should be removed by the drag or 

 otherwise as soon as safe. 



The use of numerous small fires of oil or other com- 

 bustible material to raise the temperature above the 

 frost point has been recently adopted by western fruit- 

 growers as a means of averting frosts. 



