WEATHER IN CRANBERRY CULTURE 89 



SIZE OF BERRIES AND SIZE OF CROPS 



Some large cranberry crops (e. g., those of 1923, 1926, and 1937) are of small 

 berries; but crops of berries much larger than normal (e. g., those of 1922, 1925, 

 1931, 1933, and 1942) probably are never small unless they have been much 

 reduced by such accidents as frost or winterkilling. Size of berries is evidently 

 related to crop size, but the factors that affect it often fail to work in unison with 

 others equally important that determine crop totals. 



WEATHER AND CRANBERRY RIPENING 



The only relations between the weather and the time of cranberry ripening 

 found interesting are set forth in Table 3. The dates of the first full-car ship- 

 ments of the Early Black variety by the New England Cranberry Sales Company, 

 kindly provided by the management, were used to Index the times of ripening. 

 No work with other varieties was attempted because of obvious difficulties and 

 irregularities. 



Table 3 gives the following correlations between temperature and time of 

 ripening: 



Correlation Coefificients 



March +0.384 ± 0.096 



April +0.512 ± 0.083 



May +0.335 + 0.10 



June +0.434 ± 0.091 



August -0.494 + 0.G85 



The spring months (Marrh + April + May) +0.592 ± 0.073 



The spring months + June +0.614 + 0.07 



Balance between the spring months + June 



and August (March + twice April + May 



+ June - twice August) +0.732 + 0.052 



The mean temperatures of each of the three spring months and of June show a 

 positive and that of August a negative relation to the time of ripening. April 

 and August are about equal and more important than the other months in their 

 influence, and the spring months together more important than August alorie. 

 A correlation coefficient fourteen times the probable error appears when the 

 five months Involved are roughly weighted according to their probable impor- 

 tance, shown by their Individual correlations, and August Is balanced against the 

 other months together. This Is convincing evidence that this relation is real and 

 suggests strongly that it is the main one that determines the time of ripening 

 of Early Black cranberries. This conclusion may seem to contradict the results 

 of some experiments'^ which showed earlier ripening as a consequence of watering 

 during a drouth; but other findings^ suggest that this effect came about through 

 the lowering of temperature by evaporation. The negative correlation of August 

 fits in nicely with the temperature effects on cranberry coloring obtained In the 

 storage experiments. 



July temperature shows no relation to the time of ripening. Cranberry vines 

 in that month, being in bloom and setting their fruit, probably are in a condition 

 of transition or balance between the earlier temperature influence and that of 

 August. 



^Mass. Agr. Expt. Sta. Bui. 271:250, 1931. 



«Mass. Agr. Expt. Sta. Bui. 293:23-24, 1933; 347:9, 45, 1938; 355:52, 1939. , 



