222 FRUIT CULTURE UNDER GLASS. 



independent of each other. Although great blunders 

 have now and again been committed in glazing such 

 houses with obscure glass, it need scarcely, at this 

 period of horticulture, be necessary to warn against 

 such glass in the case of all forcing-houses intended 

 for tropical fruits. 



It will be seen from the section of the house I 

 recommend, that the bed for the soil is 18 inches 

 deep. This depth may not be necessary for very early 

 and late forcing, but for crops in the heat of summer 

 I recommend a depth of soil of from 12 to 14 inches, 

 according as the loam may be lighter or more adhesive 

 in texture ; and have a decided objection to laying 

 the loam on the pavement without an intervening 

 layer of at least 4 inches of broken bricks or stones, 

 so as to let water escape freely from the soil, thus 

 keeping it sweet and wholesome. I have always 

 noticed that a body of close soil laid on smooth stone 

 or wooden surfaces, without some material to act as 

 drainage, becomes soured and inert next these sur- 

 faces. The side ventilators, whether they be in the 

 form of glass upright lights or wooden ventilators in 

 the side walls, should have perforated zinc nailed 

 over the openings, to moderate the entrance of cold 

 air when such is required ; and the openings should 

 be either directly under or opposite the hot-water 

 pipes, so that the air may be heated in entering the 

 house. Unless it be in summer weather, when the 

 fruit are setting or ripening, I do not recommend front 

 or side ventilation. My general aversion to very small 

 houses, where a steady and high temperature has to 

 be maintained, is as strong in the case of melons 

 as in that of forcing vines and peaches ; and conse- 

 quently I recommend something more extensive than 



