46 THE TEMPERATURE FACTOR 



product in temperate climates during the normal season of weather 

 favorable to their development. Such crops can be planted in 

 the open ground after the weather has become sufficiently warm 

 in spring, and will complete their growth and mature their crop 

 before the plants are killed by the frosts of autumn. This group 

 includes string beans, Lima beans, sweet corn, cucumbers, gherkins, 

 muskmelons, watermelons, okra, squashes and pumpkins. Of 

 these crops, string beans and sweet corn will germinate at a lower 

 temperature, and hence can be planted earlier, than the Lima 

 beans and the vine crops. All the crops in this group demand 

 warm weather, but some of them will suffer if the weather is 

 excessively hot and dry. Those most resistant to drought are 

 gherkins, watermelons and okra; and these crops are especially 

 adapted to southern localities. 



Some of the vegetables in this group will not mature in the 

 extreme northern part of the United States unless transplanting 

 is resorted to, as in the following group: 



(2) The second group of warm season crops consists of those 

 having so long a period of growth that they are unable to mature 

 a full crop in temperate climates unless started under glass con- 

 siderably in advance of the normal season for weather suited to 

 their growth in the open. This group includes eggplants, peppers, 

 sweet potatoes and tomatoes. Of these, eggplants and sweet 

 potatoes demand a higher temperature than tomatoes and peppers, 

 and under normal seasonal conditions should not be transplanted 

 to the open ground until two or three weeks after the ideal time 

 for setting tomatoes. Eggplants and sweet potatoes are especially 

 suited to growing in localities subject to severe drought, for after 

 these plants have once become well established, their demands 

 for moisture are not great, and the more intense the heat, the 

 better they grow. 



Importance of Season. — The wide differences in the tempera- 

 ture and moisture requirements of the various vegetable crops, 

 as above outlined, explain why some crops thrive much better 

 some seasons than others, in the same locality, and also why 

 certain crops are most extensively grown in certain localities. 

 However, careful attention to the time of planting each crop in 

 view of its particular temperature requirements, will enable the 

 gardener to' grow to perfection a much larger assortment of vege- 

 tables in the same garden than could possibly be done without 

 consideration of the specific requirements of each particular crop. 



