134 GARDENING FOR BEGINNERS 



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 lower- 

 ing 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. 



Posit/on. Where a choice of position exists an unusual occurrence, 

 except in large gardens a span-roof structure should run east and west, 

 thus allowing the midday sun to shine full on its side. 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 required. 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- 

 side of the glass with a painter's brush, and if the sun is shining on the 

 glass at the time so much the better. This shading gradually thins, so 

 that by the autumn, when the sun loses power, there is little left. 



In a sunny spot when the shading is on rollers it may be used during 



