664 PARKS 



Of course some requirements demand several compartments to ensure dif- 

 ferent growing temperatures, in which case the eighteen, twenty-five or 

 thirty-foot house is doubtless best for general park purposes. When it 

 comes to bench and walk widths, follow the experience and advice of green- 

 house experts. 



Ridge and furrow versus separate houses. There is much divergence of 

 opinion as to the comparative merits of separate houses as against those 

 built together. Ridge and furrow does make possible better ventilation, 

 but this is offset in snowy sections by the way the snow piles up between 

 the houses, causing shade at just the time of year when light is so essential. 

 For the same amount of money more space can be covered with ridge and 

 furrow houses, but the fact that in most sections of the country there is 

 only one such layout to every ten or more of separate houses indicates that 

 the separate houses are to be preferred. 



Construction. In these days the semi-iron or pipe frame and the full 

 iron frame house has taken the place of the all-wood house. The semi-iron 

 (Plate 248) is a thoroughly good house, costing from ten to fifteen per cent 

 less than the iron frame house. As far as growing conditions are concerned 

 there is very little or any difference. The main difference lies in the rigidity 

 of the frame. The semi-iron or pipe frame has no rafters. The roof depends 

 entirely for its support on the added size of the glazing bars and the pipe 

 purlins supported about every eight feet with pipe columns. 



The iron frame (Plate 249) is of entirely self-sustaining construction, 

 rigid and strong of itself. The roof bars, serving only as glazing members, 

 can be much lighter and so cast less shade. The semi-iron house must have 

 numerous columns, while even a house seventy feet wide, of iron frame con- 

 struction, requires only two columns across its width. As a permanent 

 investment, unquestionably, the iron frame is the best type of house. Its 

 upkeep is lower and there is less glass breakage because of its greater rigidity. 



Wood. One of the oldest and largest firms of horticultural builders 

 states that, after having experienced and made extensive tests with various 

 woods over a period of close on to three-quarters of a century, it has come 

 to the conclusion that no wood so well meets the demands of combined 

 strength and resistance to rot as tidewater tank cypress, that is sap free. 

 Government statistics bear out this firm's conclusions. 



Design. There are three rather distinct designs, one of which is prac- 

 tical for the semi-iron and all for the iron frame type of house, (a) For 

 both types of houses the so-called eaves plate design is adaptable. This 

 has an angle iron eave plate at the eave line. To it are secured the roof bars 

 and the side sash hinged. It makes a rigid, enduring eave that casts the 

 minimum shade, (b) The iron frame gutter house, which has the same 



