34 STUDIES IN GARDENING 



a stiff clay without a thorough and deep preparation 

 of the soil. 



The soil also should be carefully prepared where 

 any annuals are to be sown, for a stiff clay is by nature 

 too hard and rough and uneven, even when thoroughly 

 broken up, for seeds to germinate well in it. Indeed, 

 on clay one seldom sees those self-sown seedlings which 

 are so common in a sandy soil; and even trees repro- 

 duce themselves from seed much more rarely, which 

 is, no doubt, the reason why light soils are apt to 

 be more wooded than heavy ones. Therefore, when 

 seeds are sown out of doors on clay the surface of the 

 soil should not only be very thoroughly broken up, 

 but should be enriched and softened with leaf-mould 

 and grit. It is seldom much use to sow annuals in 

 autumn on clay, though it is the best way of growing 

 many kinds on a light soil. Indeed, all annuals should 

 be sown, even in the spring, some weeks later on clay 

 than on sand. In the case of biennials and perennials 

 many kinds which can be sown in the open ground 

 when it is sandy should be sown in boxes of prepared 

 soil where the natural soil is clay, since not only are 

 they apt to fail to germinate, but they are also liable 

 to be eaten off by slugs while still in a young and 

 tender state. Slugs and snails are perhaps the worst 

 pests of a heavy soil, and there is no means of extir- 

 pating them. They can only be dealt with in detail 

 by killing all that are encountered and by surround- 

 ing the plants for which they have a particular fancy 

 with soot or ashes. Not only is the voracity of slugs, 



