Relation of Weather to Crops 105 



After the early part of April the weather is sufficiently warm 

 for tomatoes to begin making more rapid growth, and until the 

 first of June most varieties grow with increasing rapidity. As the 

 weather grows warmer, only the varieties with heavy foliage con- 

 tinue thrifty. All varieties with finely divided or thin foliage are 

 seriously injured by heat during June, and none of them produce 

 much fruit. Only the Dwarf Champion, and a few related varieties 

 with heavy foliage, can be counted on to produce a crop regularly. 



Fruit begins ripening during the latter part of June and increases 

 in quantity until the middle of July. The vines continue to make 

 some growth and to ripen fruit until about the middle of August. 

 While they continue blossoming some through the summer, no 

 fruit is ordinarily set after the middle part of July. Hence,, none 

 ordinarily ripens during the latter part of August, or during Sep- 

 tember. As the weather becomes cooler during the latter month, 

 fruit again begins to set. It begins ripening during the latter part 

 of October, the total amount of the crop depending upon the earli- 

 ness of the fall frosts. The vines are usually killed during the latter 

 part of November or the early part of December. In 1899, they 

 were killed December 10, and in 1900 not until December 27. In 

 1901 they were slightly injured December 8, when the minimum 

 temperatures were 27° at the ground, 81° in the government shelter, 

 and 36° at the Weather Bureau, and were nearly killed the next 

 morning, when the minimum temperatures were, respectivelyt 25°, 

 28°, and 33° at these points. In 1902, they were slightly injured 

 November 16, when the minimum temperatures were 31° at the 

 ground, 35° in the government shelter, and 43° at the Weather 

 Bureau, were considerably injured November 26, when the minmium 

 temperatures were, respectively, 29°, 32°, and 34° at these points; 

 were partially killed November 28, when the minimum temperatures 

 were 27°, 30°, and 34°; and were killed December 3, when the mer- 

 cury fell to 24°, 28°, and 33° at the above points. During 1903 they 

 were killed December 5, when the record showed minimum tem- 

 peratures of 25° at the ground, 30° in the government shelter, and 

 ?5^ at the Weather Bureau.' 



By comparing the records of spring and fall frosts it will be 

 seen that young tomato plants endure quite as low temperatures 

 as mature ones, and in some cases were uninjured by lower tem- 

 peratures than seriously injured full-grown vines. In the fall, fresh 

 growth is usually injured less than older growth, indicating that 

 more vigorous action on the part of the plant renders it less suscepti- 

 ble to the effects of frost. 



