36 THE NURSERY 



for this. These manures should only be used on the cleaning 

 crop, as, if applied directly to the trees, it might prove too 

 stimulating, and the wood of the young trees would not get 

 properly ripened. 



(1) Seed Beds. 



These must always have a very fine tilth, and a small 

 amount of sifted rubble or ashes should be raked over the 

 top soil, so as to prevent the soil from " running " together 

 and forming a " cake," through which the seedlings of small 

 seed would have great difficulty in piercing. 



Over such beds as require special protection, a screen of 

 " peignon " or chestnut pale fencing may be stretched over a 

 light frame-work about 2 feet 6 inches from the ground. 

 This is by far the most convenient way of affording to tender 

 species protection from late frosts in the spring or early 

 frosts in the autumn, and also, provided the beds run north 

 and south, of affording protection from hot sun. 



These screens can be very quickly rolled up, when their 

 protection is not required. 



For instance, they might be rolled up every morning and 

 unrolled every evening during the end of April and all 

 through May as a protection against night frosts. A cheaper 

 method of affording this protection, but one not nearly so 

 convenient, is to place branches of birch, with the leaves on, 

 across the bed from side to side. 



Under no circumstances should branches of conifers be 

 used for this purpose. 



(2) Liability to Frosts. 



Silver Fir and Beech are perhaps more in need of this 

 protection than any other common species. They are very 

 sensitive to frosts in the spring and autumn and also to hot 

 sun, at any rate for the first few years of their existence. 



Most young trees will succumb to or be seriously injured 

 by late spring and early autumn frosts, but of those especially 

 tender, besides Silver Fir and Beech, may be mentioned 

 Black Walnut, Weymouth Pine, Acacia, Ash (all varieties), 



