1400 



GREENHOUSE 



GREENHOUSE 



culls and lights only fit to glaze cheap sash for market- 

 gardeners, and is of doubtful economy even for this 

 purpose. Rough plate and ribbed glass is used on large 

 palm-gardens and conservatoiics in which the maximum 

 of light is not an essential feature. Where this glass is 

 used larger roof-bars are needed and stock construction 

 has to be materially changed. Recently a few conserva- 

 tories have been glazed with thick, polished plate- 

 glass, making very handsome roofs, but rather expen- 

 sive. 



To set glass properly in a greenhouse roof, it should 

 be bedded in the best putty on wood sash-bars and 

 lapped at the joints. The bars should be spaced accu- 

 rately, so that the glass will fit the rabbets with not 

 over YE of an inch allowance, and the panes of glass 

 should lap each other not more than from }^ to }^ of 

 an inch. Zinc shoe-nails fasten the glass best, using 

 from four to six to each pane, according to the size of 

 the light. No putty should be used on the outside of 

 the glass. A comparatively new system of glazing has 

 been adopted by some florists in which no putty is 

 used, but the glass is placed directly on the rabbets of 

 the bars and the ends of the panes are butted together 

 and held in place by wood caps fastened to the sash- 

 bars. This system does not make a tight roof, allowing 

 considerable water to enter the house through the joints, 

 nor does it provide any means of escape for the con- 

 densed water from the under side of the glass, which is a 

 very serious objection. In ordinary glazing, where 

 each light laps over the one below, the condensed water 



1758. Details of iron-frame benches. 



passes through the joints to the outside, forming a 

 perfect remedy for this trouble. The difference in the 

 cost is very slight, if anything, provided the work is 

 equaDy well done, as the value of the putty omitted 

 is fully offset by the extra cost of the caps. 



The painting of a greenhouse roof is a very impor- 

 tant part of the work. Owing to the extremes of heat, 

 cold, dryness and moisture to which it is exposed, the 

 conditions are decidedly different from ordinary build- 

 ings. Three-coat work is the best. The priming coat 

 on the woodwork should be mostly oil, and, as far as 

 possible, the material should be dipped into a tank of 

 paint. Iron and steel framing material should be primed 

 with a metallic paint. The priming coat should be 

 applied before the material is exposed to the weather. 

 The material of the second and finishing coat should 

 be pure linseed oil and white lead. Experience has 

 shown that this material is the best for this work. The 

 color should be white or a light tint of any desired shade 

 may be used, but no heavy color should be adopted 

 which requires coloring matter in place of the lead in the 

 mixing. Each coat should be applied thin and well 

 rubbed out. While the appearance may not be quite 

 so fine when the work is first done, the paint will not 

 peel off, and will last longer and form a better protection 

 for the structure than when it is put on in thick coats. 

 It will also form a good base for repainting, and this 

 should be done in a similar manner. It is economical 

 to repaint a greenhouse every two years, and generally 

 one coat will be sufficient. Neglected unpainted green- 

 houses soon suffer, and are also very unattractive. 



Plant-tables. 



Stages for plants in pots, or raised beds for planting 

 out, usually cover the entire area of a greenhouse except 

 the walks, and their cost constitutes a considerable 

 proportion of the expense. Pakns are usually grown in 

 solid beds or in pots or boxes sitting on the ground. 

 Many vegetables are grown in solid beds near the 

 ground-level. Roses and carnations are usually in 

 raised beds. Angle-iron frames supported on adjusta- 

 ble gas-pipe legs, with slate or tile bottoms, form the 

 best plant-tables (Fig. 1758). Wood bottoms which 

 can be readily renewed are frequently substituted, sav- 

 ing a part of the first cost. Wlien the table supports are 

 of wood, care should be taken that they are not fastened 

 against any part of the framework of the house, unless 

 iron brackets are used so as entirely to separate the 

 woodwork. 



Ventilation. 



No greenhouse is complete without a good ventilating 

 apparatus. About one-tenth of the roof should be 

 arranged to open or close for ventilation, although this 

 percentage will vary according to the form of house and 

 the purpose for which it is used. It is not desirable to 

 open all the ventilators in a long house with one set 

 of apparatus, for frequently one end will not need so 

 much ventilation as the other end or may be affected 

 by the wind, forming a current lengthwise of the house. 

 To avoid this, a greenhouse 200 feet long should have 

 three or four sets of apparatus which can be operated 

 separately. In all greenhouses of considerable width 

 it is desirable that ventilation should be provided on 

 both sides of the ridge so that the ventilation can be 

 given on the "leeward" side, which will prevent the 

 wind from blowing directly into the house. 



Heating. 



The success of the florist, gardener or amateur in 

 the management of a greenhouse depends largely on 

 the satisfactory working of the heating apparatus. 

 There are two systems of greenhouse heating which, 

 when the apparatus is properly installed, are economi- 

 cal and satisfactory; viz., hot water and steam. The 

 open-tank hot-water heating has more advantage in 

 its adaptation to general use than any other, and is 

 so simple that its management is readily understood by 

 anyone. It is practically automatic and is capable of 

 maintaining an even temperature for ten hours without 

 attention. Low pressure steam-heating is well adapted 

 to large commercial ranges, and to large conservatories 

 in parks and private places where a night attendant can 

 be kept in charge of the fires to turn on and shut off 

 steam from the radiating pipes as the changing outside 

 temperature may require. The heating of greenhouses 

 to the best advantage, under the varying conditions of 

 climate and interior requirements, demands, like the 

 designing of greenhouses, the services of an experi- 

 enced speciaUst in horticultural work. 



Lord & Btjbnham Co. 



Vegetable forcing-houses. 



The evolution of the vegetable forcing-house has 

 been rapid and very pronounced. From the low-built, 

 flue-heated, dark stuffy type of house to the high, well- 

 lighted, steam- or hot-water-heated, well- ventilated 

 house is a change that has come not only in a very 

 short time but which has been as marked as the transi- 

 tion from the ox-cart to the automobile. 



Location. 



In selecting a suitable location for vegetable forcing- 

 houses, one of the most important things to consider 

 is the marketing possibilities. It would be folly to go 

 to the expense of building a forcing-house in which to 

 grow vegetables to make money if they could not be 



