﻿FREEZING TEMPERATURES OF FRUITS, VEGETABLES, AND FLOWERS. 7 



Sweet potatoes. — The results of freezing 20 more or less common 

 varieties of sweet potatoes are presented in Table 2. The varieties 

 with the lowest freezing points are Big Stem and Georgia, both of 

 which froze at 28.05° F. The highest freezing points were found 

 with Pumpkin and Yellow Jersey varieties, which froze at 28.98° 

 and 28.97° F., respectively. The average of all varieties was 28.44° F. 



Tomatoes. — The freezing temperatures of 19 commercially grown 

 varieties of tomatoes were determined and are presented in Table 2. 

 These tomatoes were all grown under the same conditions at the 

 Arlington Experiment Farm. Determinations were made on both 

 ripe and practically full-grown green specimens, such as are usually 

 picked for shipment from the Southern States to the northern 

 markets. With the ripe tomatoes the lowest freezing point (29.78° 

 F.) was found in connection with the New Glory variety. The Early 

 Michigan variety froze at 30.67° F., which represents the highest 

 freezing point of all the varieties studied. There was no appreciable 

 difference in the average freezing points of ripe and green tomatoes, 

 the averages being 30.38° and 30.40° F., respectively. 



Sweet corn. — The freezing point of sweet corn varied considerably 

 with the age of the product. There was also considerable variation 

 between varieties. Four varieties were studied. (See Table 2.) 



Miscellaneous vegetables. — The freezing points of three varieties of 

 onions, three varieties of lettuce, two varieties of carrots, and three 

 varieties of peas, and of at least one variety each of beans, cabbage, 

 cauliflower, eggplant, kohl-rabi, and turnips are also presented in 

 the. body or in the summary of Table 2. 



FREEZING POINTS OF CUT FLOWERS. 



Requests have been received for information on the freezing points 

 of such cut flowers as are commonly held in cold storage or shipped 

 in quantities. Determinations were made for peonies, roses, and 

 Easter lilies, and these are presented in Table 3. Results are shown 

 for both petals and leaves. With peonies and roses the petals freeze 

 at temperatures higher than do the leaves. Rose petals froze at 

 30.04° F., while peony petals did not freeze until a temperature of 

 29.05° was reached. In the case of Easter lilies the leaves froze 

 before the petals, the latter not succumbing until the temperature 

 reached 27.50° F. 



Table 3. — Average freezing points of the petals and leaves of cut flowers . 



Scope of inquiry. 



Peony. 



Rose. 



Easter lily. 



Petals. 



Leaves. 



Petals. 



Leaves. 



Petals. 



Leaves. 





12 

 29.05 



8 

 28.39 



6 

 30.04 



6 

 28.27 







Freezing point 



° F.: 



27.50 



29.20 



RECAPITULATION. 



Freezing or freezing injury does not always occur when fruit or 

 vegetable products are exposed to temperatures at or below their 

 actual freezing points. Under certain conditions many of these 

 products can be undercooled; that is, cooled to a point below the true 

 freezing temperature of each and again warmed up without freezing 

 and without apparent injury. Certain products under certain con- 



