688 



GREENHOUSE 



GREENHOUSE 



darken a house in the cold winter weather, when light 

 is most needed. The double-boarded sides, when erected 

 with care, are warmer than ordinary masonry walls. 



Cast-iron gutters are provided to collect the rain- 

 water from the roof. By exposing the inner side of 

 these gutters to the heat of the house, they are kept 

 free of ice in the winter. Small metal clips fastened 

 with screws are used to connect the wood sash bars to 

 the cast-iron gutters, angle-iron plates and purlins. 

 This method of securing the sash bars in place is very 

 convenient in case of repairs, and renders the structure 

 practically portable. A careful examination of any old 

 Greenhouse will show that the parts of the frame which 

 decay first are those pieces of wood which are joined 

 together, for water penetrating the joints soon destroys 

 the wood. This trouble is largely avoided by arranging 

 the frame so that each piece of wood is fastened directly 

 to the iron frame instead of to another piece of wood. 

 Joints between wood and iron do not rot the wood, the 

 latter being preserved by the corrosion of the metal. 



The curvilinear form of house (Pig. 990) is ornamen- 

 tal and particularly well adapted for conservatories, 

 palm houses and show houses of all kinds. It is pre- 

 ferred for vineries and fruit houses, as the form allows 

 the canes to be supported on the line of the roof with- 

 out a sharp bend at the plate line. The light in a 

 curved house, being admitted at different angles, is 

 better diffused and more natural than when reflected 

 through a long pane of straight glass. The cost of a 

 curved roof is slightly greater in the construction, but 

 the arched frame is stronger and will keep its shape 

 better than a house with straight lines, thus largely 

 compensating for the extra cost. For special purposes 

 and locations, special forms of frames may be used. 

 Good forms of commercial houses are shown in Figs. 

 991, 992. The latter is the most popular form for the 

 forcing-house. 



For small Greenhouses and those adapted for the use 

 of amateurs, a frame made chiefly of wood will be found 

 quite satisfactory. An improved method of framing is 

 to use small rafters of wood from 5 to 8 feet apart, with 

 cast-iron brackets at ridge and plate; these rafters are 

 connected by light angle-iron cross purlins, and the 

 latter support very light sash bars spaced for glass 

 between the rafters. The ridge is usually supported by 

 gas pipe posts, and when the rafters are of consider- 

 able length additional supports are placed under their 

 centers, instead of darkening the house by rafters of 

 greater size. In this way the roof can be made as light 

 as the metal construction first described, and will nearly 

 approach it in durability and finish. Details of con- 

 struction of wooden houses are shown in Figs. 993, 994. 



It is generally admitted that the so-called "sash bar 

 construction" is not the best or lightest method of con- 

 struction, but as the absence of most of the framing 

 reduces its cost so that it is the cheapest to build, it 

 remains a popular method of putting up a commercial 

 Greenhouse. Circulars showing the various methods 

 adopted by the dealers in Greenhouse material 

 can readily be obtained by applying to them. 



The best wood to use for Greenhouse 

 framework and plant-beds is undoubtedly 

 cypress. In purchasing this lumber, 

 care should be taken that only that 

 grown in the states bordering on 

 the Gulf of Mexico be se- 

 lected. This will be found 

 of a dark red or brown 

 color, quite soft and easily 

 worked. There is an in- 

 ferior variety of cypress 

 growing farther north . 

 which is light in color, 

 hard and springy, and apt 

 to be shaky. As the latter 

 variety is cheaper than red 

 gulf cypress it is frequent- 

 ly used by those who do 

 not know the difference, to 

 the serious detriment of 

 the work and the loss of 

 reputation of cypress for 

 such purposes. 



In the market there are three grades of cypress 

 lumber, and it is important to know which to select. 

 The best grade is known as "firsts and seconds," and 

 calls for lumber with a small amount of sap on the 

 edges and occasionally a small sound knot. This is the 

 quality which should be ordered for all the framework 

 of the roof, sash-bars, etc. In order to make the ma- 

 terial entirely free from sap there will be a waste in 

 cutting up this quality of from 10 to 20 per cent. The 

 second grade is known to the trade as "selects." TLis 

 name indicates that it has been graded so that one face 

 of each piece of lumber is of about the same quality as 

 the "firsts and seconds," the other face generally being 

 largely sap. This quality is only fit for outside board- 

 ing in Greenhouse construction; it has too much sap. 

 The cost is usually about five dollars per thousand less 

 than the best grade. As it looks to the inexperienced 

 eye almost the same as the best grade, too much of it 

 finds its way into Greenhouse structures. Such sap 

 lumber will not last more than from two to five years. 

 Too great care cannot be exercised to avoid its use. The 

 third grade of cypress lumber is termed "cutting up," 

 and is so called because it embraces all the pieces Avhich 

 have imperfections, such as large knots, splits, etc., 

 which bar them from the better grades. This is a good 

 quality to purchase for base boards and plant tables, for 

 by cutting out the sap and objectionable knots it will he 

 found satisfactory for these purposes. The "cutting 

 up " grade costs about ten dollars less per thousand than 

 the "firsts and seconds." The percentage of waste in 

 cutting up will be somewhat greater than in the other 

 grades. 



Cypress lumber which has been in use for gutters, 

 sash-bars, plates, etc., in Greenhouses where high tem- 

 peratures have been maintained is still, after many 

 years, apparently in as good condition as when first 

 used. Owing to the porous texture of the wood, the 

 paint, when applied, sinks in and does not make as fine 

 a coat as on some other woods, but Because of this fact 

 the paint adheres to the wood better and lasts longer. 



Glazing and Pa inting. Ordinary sheet or window 

 glass is in general use for greenhouse glazing. It is 

 better to use only the thickness known to the trade as 

 "double thick." This weighs from 24 to 26 ounces per 

 square foot* The thickness known to the trade as 

 "single thick" weighs only about 16 ounces to the 

 square foot, and is entirely too frail for the purpose. 

 There is very little difference at present in the quality 

 of the imported French or Belgian and the Americj 



Three-quarter-span Rose- or Carnation-house 

 Cast-iron piping. 



