282 GARDENING FOR BEGINNERS 



In narrower houses these dimensions may be proportionately reduced. 

 For a house sixteen feet wide a central stage is necessary. It may be 

 four feet in width, with a walk of three feet on each side, and an outside 

 stage of the same dimensions sixteen feet in all. Ample ventilation is 

 essential, and this should be provided for by means of lifting or sliding 

 lights on the top, and also in the sashes around the sides, while if it is to 

 be heated by hot-water pipes, a few wooden traps in the wall close to 

 the pipes are serviceable. By means of these a little air may be given 

 in the winter, when the pipes are hot, without lowering the temperature 

 to any extent, the cool air admitted by this means serving to neutralise 

 the drying effects of the hot pipes. 



For a lean-to greenhouse the question of ventilation applies with 

 equal force, but, of course, the arrangement of the staging is quite differ- 

 ent from that of a span-roof structure. The usual plan is to have a 

 stage along the front, then the path, and at the back of the house a 

 stage arranged in a step-like way, so that the plants can obtain a full 

 amount of light and air. 



Various materials are used for staging, one of the neatest and most 

 permanent being slates, but their cost is frequently prohibitive. If the 

 stage is made of ordinary deals, two good coats of red-lead priming must 

 be given before applying the paint. Flat stages should be covered with 

 a moisture-retaining material, and for this purpose nothing is better than 

 the sea shingle, largely composed of cockle shells, used so much for 

 paths, &c. Besides retaining the moisture, it is sweet, clean, and does 

 not harbour insects. Other materials may be used, such as fine gravel, 

 with the sand sifted out, ashes, &c., but shingle is the most satisfactory. 



Position. Where a choice of position exists an unusual occurrence, 

 except in large gardens a span-roof structure should run north and 

 south, so that both sides of the house will be exposed to the sun some 

 time during the day. With a lean-to one must take advantage of an 

 existing wall, therefore it by no means invariably faces the south ; indeed, 

 it is sometimes almost entirely shaded. Even when a greenhouse is shut 

 off from the sun it may be made attractive, though the selection of plants 

 for this purpose will be different from that in a sunny spot. Hardy Ferns 

 would succeed in a shaded house. 



Shading. Though, as stated, a greenhouse in a quite shaded place 

 is suitable for only a small collection of plants, yet full sun is injurious 

 to so many subjects that shading is absolutely necessary, and that not 

 only for the sake of the plants themselves, but for comfort too. The 

 most desirable form of shading material is some kind of canvas fastened 

 on rollers, so that it can be drawn up when not requried. This needs 

 constant attention, therefore many prefer permanent shading. Nume- 

 rous mixtures are sold for the purpose. One that can be thoroughly 

 recommended is known as " Summer Cloud." 



A good home-made permanent shading can be formed by placing 

 seven pounds of size in a pail, and standing it over the fire until dis- 

 solved, then stir in a knob of whiting, pounded fine, and one pound of 

 Brunswick green. This must be applied, while still warm, on the out- 



