CH. ivj Late Frosts 69 



crops are grown or, as we shall soon see, fruit; still 

 higher comes grass land, especially in the cold north, 

 while above the 600 or 700 ft. contour is wood or waste 

 land. 



The small difference in temperature between a north 

 and a south slope may have a considerable effect on the 

 crop, vegetation on a south slope being a little more 

 forward and ready for market before that on the north. 

 In ordinary agricultural practice this is not usually of 

 much importance but it is for market garden work; 

 amazing differences in price are often attached to small 

 differences in time of marketing. 



More important, however, than high mean tempera- 

 ture is the absence of spring or autumn frosts. Low 

 lying valley lands are peculiarly susceptible to frosts on 

 clear calm nights; the cold air drifts down from above 

 and collects in the valley where it chills the trees and 

 not infrequently kills the fruit blossom and the tender 

 shoots of early potatoes. Land lying above this stagnant 

 pool of cold air escapes these frosts and is therefore a 

 safer place for susceptible crops, even though its mean 

 temperature may be lower than that of the valley. 

 Where, however, the low land adjoins the sea or any 

 great body of water it is protected from these frosts and 

 is, indeed, better than land Ijing further off because it 

 is warmer. 



We can now understand why fruit is so often grown 

 in undulating country. Slopes are needed to give the 

 desired shelter and aspect, but above all to avoid risks 

 of late frosts. The "lucky banks" of the Evesham 

 district, on which crops can nearly always be got, are 

 of this character. In the fruit-growing region of Kent 

 the fruit tends to collect on the middle slopes, hops on 



