Greenhouse Construction for Vegetable Grow^ers 



Robt. W. King, Toronto 



WHEN contemplating the erection 

 of' a glass house for vegetable 

 growing, the first question that 

 broadly presents itself is "what is the 

 best kind of a house to build?" 



A very good article on greenhouse con- 

 struction for vegetable growers by J. 

 D. Fraser, Leamington, Ont., is pub- 

 lished in the annual report for 1907 of the 

 Ontario Vegetable Growers' Association. 

 rVom his experience, the following point- 

 ers may be gleaned : 



1. Greenhouses should be sheltered 

 from the wind. 



2. In no case is it advisable, either 

 for defence or protection, to exclude sun- 

 light. "Admit," he says, "every pos- 

 sible ray of sunlight." 



3. Discard wood as much as possible. 



4. For supports, use gas pipe set in 

 cement. 



5. For sash bars and other necessary 

 wood work, cypress is preferred and 

 must be painted. 



Fig. 1. Sath Being Used for Side Ventilation 



Where a largo amount of .side ventilation iH required, 

 side Hash can be hinged ut the eveH, or whore the eves 

 are too high a header may be run along the Hides of the 

 houHo, and the sash hinged to it as is shown in the 

 illustration. The header is carried by special brackets 

 bolted to the posts. 



6. Vegetables, for proper finishing, re- 

 quire a free circulation of air and lots 

 of ventilation. 



7. There is not sufficient air in very 

 low houses. 



8. Mr. Fraser builds hou.ses with four- 

 teen feet spans, connected in blocks up 

 to 100 feet wide ; but for a house only 

 thirty-five to forty feet wide, he prefers 

 a single span. 



g. Large houses are easiest to heat. 



10. Don't give a man a contract to put 

 in pipes unless you are sure he knows 

 how to do it. "The ordinary plumber 

 doesn't know anything about heating a 

 greenhouse." 



As regards nine of the ten pointers 

 quoted from Mr. Fraser's paper, it is 

 needless to refer to any authority, eith- 

 er in support or contradiction. The only 

 one not accepted or that called forth 

 any question from the numerous experts 

 assembled was No. 8 which refers to the 

 width and height of the houses. And 

 this has been just as much a question 

 with florists with whom we have asso- 

 ciated for the last fifteen or more years, 

 as it is with the vegetable men to-day. 



LIGHT AND VKNTILATION 



There are some plants and flowers that 

 like shade and others that thrive better 

 in the sun, but they all want light and 

 air. As the art is not to succeed under 

 glass in the summer when the sunshine 

 and light is in plenty, so much as to pro- 

 duce during the dark days of winter 

 when prices are up and the sun is down 

 the nearest approach to summer out-of- 

 door conditions, we want it in our power 

 to admit every possible ray of light, even 

 if we have to do .some shading in the 

 summer months. As regards the con- 

 struction of the houses for ventilation, 

 as much as is required should be secur- 

 ed for the summer months with as little 

 increase as possible to the shadow of the 

 sash during the darker days in winter. 



SINGLE vs. CONNECTED HOUSES 



Regarding the width of houses, the 

 question of the day seems mainly to be 

 between blocks of comparatively narrow 

 houses built high and single separate 

 houses of widths ranging from forty to 

 sixty feet. For commercial purposes, 

 the low, narrow, single house has long 

 since become one of the mistakes of 

 the past. 



The advantages claimed for separate 

 houses are: (i) The additional light on 

 the first bed facing the south, the houses 

 being placed a good distance apart ; (2) 

 the ability to obtain side ventilation ; (3) 

 in the colder climates the avoiding of the 



168 



piling-up of snow in the valleys, especial- 

 ly where the colder temperatures are re- 

 quired to be maintained. 



The disadvantages are the extra ex- 

 penses in a large plant of houses, of 

 the said outside walls and side ventilat- 

 ing, together with the large extra cost 

 per square foot of growing surface for 

 real estate, fuel and boiler plant to heat 

 the same. This has lead to the present 

 idea (by advocates of separate houses) of 

 building them extra wide until in a case 

 of a house 150 feet wide by 500 feet long, 

 a whole block is enclosed in a single 

 span, but in such cases, there is no more 

 advantage as regards side light than 

 would be obtained in a block of narrower 

 houses of the same size. 



In such houses, other objections ma- 

 terialize, as, for instance, the large ex- 

 tra amount of end glass to install, wind 

 brr.tes and heat in the winter. .Another 

 objection is the limited amount of ridge 

 ventilation practical to be installed, also 



Fig. 2. Method of Ventilation at the (iround 



The glass over the wall is intended to reach to within 

 one foot of the ground. The wall is formed by setting 

 a two by six plank edgewise. The plank is carried by 

 special brackets bolted to Ihe posts of the house. An 

 opening is left at ground for ventilator which can be 

 banked up in cold weather. 



