SHADING AND VENTILATION 55 



plants would be quite useless for any purpose- 

 scarcely fit for rabbit food even. 



When growing Lettuces, Cauliflowers, Carrots, 

 Radishes and other crops mentioned in the following 

 pages under lights or cloches, the gardener will at 

 once recognise the great importance of giving light 

 and air at exactly the right moments, in accordance 

 with the instructions given ; and in doing so he 

 must always take the state of the weather into account. 



By using the tilts (see figs. 9 to 12) for lights and 

 cloches, or even bricks or blocks of wood, as much 

 or as little air may be given as desired. On very 

 cold days, perhaps only a " crack " of air, as gardeners 

 say, is given by placing the tilts on the lowest notch 

 or on the thinnest side ; and even then perhaps no 

 air will be given until near mid-day just for an 

 hour or so according to climatic conditions. On 

 other occasions, such as a bright balmy morning, air 

 may be given quite early, and perhaps the cloches 

 or lights will be opened to the full extent of the tilts 

 used. This is called " putting on full air." 



Whether much or little air is given, it is always 

 advisable, as already stated, to note the direction of 

 the wind. The tilt is then placed on the opposite 

 side of the cloche or light, so that the draught does 

 not blow directly on to the tender heads of the plants, 

 but passes over them without causing a chill, and 

 a possible check to the growth. 



COMBINATION AND ROTATION CROPS 



One of the most interesting and striking features 

 of intensive cultivation is the way in which the same 



