IO4 



Commercial Gardening 



a few inches of soil rest on hard rock beneath, trenching and even double 

 digging is often out of the question. 



When trenching ground, the soil is marked out in strips about 3 ft. 

 wide, and the first trench is taken out to a similar depth. Before the 

 soil adjacent is thrown into the trench in front it is a good plan to place 

 a good layer of weeds, green vegetable refuse, twigs, &c. in fact all 

 coarse and untidy vegetation at hand in the bottom. The only refuse 

 to avoid putting in the trenches is Potato haulms and the clubbed roots 

 of cabbage crops. These should be always burned to destroy the spores 

 of the terrible diseases which often afflict them. Having prepared the 

 first trench in the way indicated, the next piece of ground is marked off 

 3 ft. wide, and the soil from this, spit by spit and layer by layer, is placed 

 in the trench, until this is of course filled up, and a new trench is along- 



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AC B 



Fig. 86. Diagram showiug how ground may be trenched 3 ft. deep, bringing the bottom layer to the 

 top to be fertilized by the weather, and to allow the free passage of air, rain, and roots downwards. 

 Shaded portions indicate layers of manure. Note how trenched soil A is raised higher than the un- 

 trenched B. shows how soil has been dug out and placed at A. In B the figures 1 to 9 show how the 

 soil is to fill the trench in the same way as at A. 



side. Where plenty of refuse and manure are available it will pay to 

 place a layer between the spits, keeping the best and most rotted manure 

 for placing beneath the top spit. A kind of sandwich of soil and manure 

 will thus be formed, as shown in the diagram (fig. 86). 



Very few, if any, commercial gardeners adopt this system of culti- 

 vation, partly because of the cost of labour and manure, and partly because 

 they fear that it would be one of the greatest mistakes possible to bring 

 up the subsoil from a depth of 3 ft., and place it on the surface, especially 

 if it happens to be of a clayey, sticky nature, or of gravel. But it would 

 be well to remember the words of Virgil: 



" Well must the ground be digged and better dressed 

 New soil to make, and meliorate the rest". 



One can appreciate the argument against trenching on the score of ex- 

 pense; but if it is going to be done there will be no more, or very little 

 more, expense or labour attached to bringing up the bottom spit and 

 exposing it to all the fertilizing influences of the weather. As a rule 

 this is the case. There is only one possible danger, and that is if the 

 subsoil should contain a large proportion of ferrous oxide or protoxide 



