32 



Farmers' Bulletin 1096. 



aids considerably in protecting the plants immediately surround- 

 ing them. In planting a field to a low-growing crop that is to be 

 protected with heaters, vacant spaces about 18 inches square should 

 be left at the points where the heaters are to be placed, as the 

 plants very close to the heaters are likely to be scorched. 



Orchard heating has been practiced for six years on one of the 

 largest lemon groves in the country, located in southern California. 

 During the season of 1912-13, a season when the citrus crop in many 

 parts of southern California was practically a total loss and thou- 

 sands of trees were killed outright, the lemon crop from this grove 

 brought $734,318.07 f. o. b. California. 



On higher ground on the same ranch 5-year-old lemon trees 

 which were not protected were frozen to the ground. The mana- 

 ger of this ranch states it is his belief that the business would not 

 have been profitable since 1912 without means of protection from 

 frost. 



MAXIMUM COST OF FIRING 



Records on the cost of protecting 220 acres on this place during 

 the past six years are shown below. (Table 1.) It will be seen that the 

 returns from the fruit saved in 1913 alone would pay the costs of 

 protection for many years. About 500 acres of lemons are now 

 being protected here. 



TABLE 1. Average cost per acre for protecting 



heaters. 1 



acres of lemons with oil 



i Small open heaters used in 1913; down-draft, short stack type in later seasons. 



This ranch is located on both high and low ground, but only the 

 low ground is protected. Lemons are more easily damaged than 

 oranges, and as the small green fruit is protected here, the fires are 

 lighted oftener than in most other orchards. The costs given above 

 are for firing about the maximum number of times that would be 

 necessary anywhere in the country. 



AVERAGE COST OF FIRING 



Mr. Willis S. Jones, of Claremont, Calif., has kept accurate records 

 on the cost of firing his 40-acre orange grove, which is on rather 



