GREENHOUSE 



GREENHOUSE 



1399 



It is commonly 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 



175S. A compact two-walk house. 



greenhouse. Circulars showing the various methods 

 adopted by the dealers in greenhouse material can 

 readily be secured by applying to them. 



The best wood to use tor 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 selected. 

 This will be found of a dark red or brown color, quite 

 soft and easily worked. There is an inferior va- 

 riety of cypress growing farther north, which 

 is light in color, hard and springy, and 

 hkely to be shaky. As the latter variety 

 is cheaper than red Gulf cypress it 

 is frequently 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 pur- 

 poses. 



In the market there 

 are three grades of 

 cypress lumber, and it 

 is important to know 

 which to choose. The 

 best grade is known 



as "firsts and seconds," and calls for lumber with a 

 small extent 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, and so on. In order to make the material entirely 

 free from sap there wiU be a waste in cutting up this 

 quality of 10 to 20 per cent. The second grade 

 is known to the trade as "selects." This name indi- 

 cates 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 fit only for outside board- 

 ing in greenhouse construction; it has too much sap. 

 The cost is usually about five dollars a 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 v/ay into greenhouse structures. Such sap 

 lumber usually will not last more than 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 

 which have imperfections, such as large knots and splits, 

 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 be found satisfactory for these purposes. The 

 "cutting up" grade costs about ten dollars le.ss a 

 thousand than the "firsts and seconds." The percent- 

 age of waste in cutting up will be somewhat greater 



than in the other grades. Cheap timber is likely to 



give unsatisfactory results in greenhouse work. 



Cypress lumber which has been in use for gutters, 

 sash-bars, plates, and the hke, in greenhouses where 

 high temperatures 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 so 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 painting. 



Ordinary sheet or window glass is in general use for 

 greenhouse glazing. It is better to use only the thick- 

 ness known to the trade as "double -thick." This 

 weighs from twenty-four to twenty-six ounces a 

 square foot. The thickness known to the trade as 

 "single thick" weighs only about sixteen ounces to the 

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

 There is very httle difference at present in the quality 

 of the imported French or Belgian and the American 

 glass. The weight of most of the glass of American 

 manufacture is about 2 ounces greater a foot than the 

 imported, and therefore it is proportionately stronger. 

 This greater strength is of considerable importance in 

 the additional security which it affords from damage 

 caused by that enemy of the florists, the hail-storm. 

 There is a great difference in the quality of the glass 

 made by different manufacturers in its adaptation to 

 greenhouse use. This difference is caused chiefly 

 by the quality of the material used in the glass, 

 making it more or less opaque, and in the 

 variations in thickness causing lenses 

 which concentrate the sun's rays and 

 burn the foliage of the plants. 

 This last defect in the glass 

 cannot be wholly 

 guarded against, as the 

 product of a factory 

 does not always run 

 the same so that any 

 favorite brand cannot 

 be fullj' relied upon in 

 this respect. The waves 

 which burn will be 

 found in all the differ- 

 ent grades of glass, 

 firsts, seconds and thirds, with Uttle, if any difference, 

 the grading being done chiefly for other defects, such 

 as affect the value of the glass for window purposes. 

 For these reasons, in selecting the glass for a green- 

 house, it requires experience to decide what make of 

 glass it will be best to purchase. It will be well to pur- 

 chase from someone who makes a specialty of furnish- 

 ing glass for greenhouses or call in the aid of some 

 friend who has had experience in building, and can give 

 intelligent advice. 



The second quality of glass is usually selected for the 

 best greenhouse work. The standard widths are from 

 12 to 16 inches, and lengths vary from 1(3 to 24 inches. 



1756. Section of curved-eave house. 



1757. Ridge-and-furrow houses. 



A favorite size is 16 by 24 inches. This is about as large 

 as it is practicable to u.se double thick glass, and makes a 

 roof with comparatively few lajjs. 



It is not safe to purchase fourth quality of glass or 

 the so-called "greenhou.se glass" frequently offered by 

 window-glass dealers, as both of the grades contain the 



