August, 1908 



THE CANADIAN HORTICULTURIST 



173 



Greenhouse Construction 



(Continued from Pnut 1(J9/ 



In locations where, on account of snow, 

 lie side sflass will have to be kept up two 

 more feet, a good arrangement would be 

 use the ordinary King side wall modi- 

 ed by hinging the dead wall below the 

 ite, or otherwise to make it removeable 

 tttirely, which can be arranged. 

 Before the subject of ventilation can be 

 ^ghtly understood, it is necessary to theor- 

 te to some extent. To obtain proper ven- 

 iation, sufficient openings must be made 

 the roof to allow the over-heated^ air to 

 scape, while cooler air, due to its extra 

 height, will force itself in (even through 

 lie same aperture, if necessary) to take 

 be place of the warmer air, whose light- 

 less causes it to ascend. Thus we get the 

 xchange of air necessary to the growth of 

 plants, and which must be brought about, 

 some extent, even in the dead of winter, 

 l^t the cost of fuel for heating. But that 

 not all the question. What is usually 

 Complained of may not be so much a lack 

 of change of air, as it is the intense heat 

 "i radiation, due to two kinds of glass. 



KINDS OF HEAT 



There are two kinds of heat to consider. 

 One is heat from convection; the other is 

 heat from radiation. Convected heat is 

 -uch as travels in currents of air, and can 

 he carried away by a process of ventilation-, 

 by which movement of the air is produced. 

 ileat from radiation is that scorching heat 

 due to too close a proximity to some over- 

 heated body in the open air, and by which 

 even the moving of the surrounding air 

 may increase the distress that the heat is 

 causing. Above us, we have the scorch- 

 ing sun playing its heat on the glass. 

 Glass - intensifies, rather than obstructs, 

 the heat of radiation. In the lower strata 

 we have the cooler radiation from Mother 

 Earth. Following this theory to its legiti- 

 mate conclusions, you may find a very good 

 and convincing reason why, if other con- 

 ditions arc not allowed to interfere, or be 

 in themselves deficient, with glass carried 

 high over head, mainly in high houses, 

 they can be made cooler in summer and 

 warmer in winter, than any houses where 

 the glass is low. So that when you are 

 considering the getting rid of the convect- 

 ed heat in the nature of overheated air 

 that needs to be exchanged, you may as 

 well consider the injurious effect of the 

 heat of radiation from the glass in winter, 

 and move it further away from your grow- 

 ing space. 



Build your houses, no matter for what 

 purpose, roomy, to give lots of air, and 

 evenness of ventilation, and reasonably 

 high, to get away from the heat of the 

 glass in summer and the cold in winter. 

 _rhe best way to insure this effect will not 

 ~ to set up air currents in the houses so 

 |uch as to obtain as even a distribution 

 ventilation as possible throughout the 

 fchole of the block, not looking so much 

 Ipon getting one bed in a big house bet- 

 Br than the rest, as to get all parts of 

 he house equally good. 



SOME CONCLUSIONS 



The practical conclusions to be drawn 

 ^om the theories advanced are, to keep 

 Bur glass up, that separate houses, with 

 lide walls not less than six or seven 

 eet high, should be built wide, say up to 

 to 60 feet, and should have double ven- 

 Blation at the ridge, side ventilation be- 

 ng left optional with the grower, accord- 

 ng to the requirements of the stock raised. 

 The wider houses have an advantage in the 



glass being higher on the average than 

 in a narrow house with side walls of equal 

 height, and in having a less area of glass 

 to heat per square foot of growing space. 

 Hence the claim that the larger houses are 

 cooler in the summer, and easiest to heat 

 in the winter. 



For blocks of connected houses, a reason- 

 ably wide span should be used (up to 25 

 feet) but to obtain as good results as in 

 the separate houses, due to the elevation 

 of the glass, the side walls should be 

 higher. 



Now comes the question: "How high 

 should they be ?" Not to be thought a 

 crank on the question of high glass, allow 

 me to say that this question depends large- 

 ly on the size of the blocks you are going 

 to build. If it is a small block or a single 

 house of a block to start with, you cannot 

 afford high outside walls, because it takes 

 too much fuel and heating plant to heat 

 them, especially with the glass kept low, 

 and on the north as well as the south side, 

 as it should be. But, as the size of the 

 block increases, the proportion of outside 

 walls decreases until it is practically of 

 vey little consideration. Then you can 

 well afford to keep your outside walls 

 higher, eventually striking as good an 

 average for height of glass. Or, better, if 

 you like, than is to be obtained in the ex- 

 ample of a single house first referred to, 

 an idea that presents itself at this point, 

 is that in building a block of houses, one 

 could start with a standard height of out- 



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side wall, and keep raising the gutters to- 

 wards the centre of the block. 



Having quoted from Mr. Eraser's paper 

 as authority for vegetable growing in a 

 district where, he says, they have very lit- 

 tle snow, I may, perhaps, be excused for 

 referring to a personal conversation with, 

 perhaps, the largest vegetable grower in 

 Canada down east, where the snow loads 

 are most extreme, and who is, in conse- 

 quence, afraid of ridge and valley houses, 

 and who has recently returned from a trip 

 through the vegetable-growing' districts of 

 the United States. He is in favor of the 

 wide single houses with roof of skeleton 

 construction, so as to admit lots of light, 

 and also of keeping the outside walls up 

 higher than he has previously been accus- 

 tomed to. 



to empty a house 



In regard to emptying a block of houses 

 at the side rather than at the end, this, 

 apparently, is a hobby of Mr. Eraser's. 

 Mr. Fraser advocates a main walk in the 

 centre, and then narrow footpaths leading 

 from it to the side, driving his team along 

 side of the house when disposing of its 

 load, but since he makes his block of 

 houses 100 feet wide, it does not appear 

 what advantage, as regards the loading, is 

 to be obtained in comparison with loading 

 the team at the end, having, say, a centre 

 walk in each house section, with an out- 

 side door at the end, through which a 

 handcart, or barrow, can be run in the 



more usual manner, or a horse and cart 

 for that matter. 



In regard to the heating of a vegetable 

 house, having due regard to the possibili- 

 ty of introducing horse power in the work- 

 ing of the same, a bank of pipes may be 

 supported on each row of valley posts with 

 a pair of pipes higher up or just under 

 the gutter on either side. Then, there 

 should at least be a corresponding quantity 

 of piping in the centre of each section of 

 house to counteract the current of cold air 

 that otherwise would fall from the roof, and 

 especially from the ventilating sash, when 

 open in winter. This bank of pipe may be 

 put on special supporting uprights, set in 

 the ground, corresponding to the valley 

 and wall, supporting posts so as to be 

 low down near the ground, or, what may 

 be better still, to have this bank of pipes 

 more widely separated, and hung over 

 head, so as to leave the whole space of 

 each span clear for cultivation, and, at the 

 same time, give a more even distribution 

 of the heat. 



It is worthy of note that in the North 

 Wales house, over 150 feet wide, after put- 

 ting a reasonable amount of pipe on the 

 two outside walls, the main body of the 

 piping is hung on flie roof, directly under 

 the glass. If this answers at all satisfac- 

 tory (and it is claimed that it does) then, 

 surely to hang fifty per cent, of the piping- 

 only, say, eight or nine feet from the 

 ground, should be all right. One of the 

 arguments in favor of this plan is that, 

 naturally, heat comes from above, and that 

 the thing to avoid in winter is the falling of 

 cold air from the glass by compelling it 

 to first pass the heating pipes. If this 

 plan is tried, it will be well to keep the 

 pipes pretty well up, and not immediately 

 over the walks, as a heating pipe too near 

 the heads of the workmen is liable to cause 

 some distress in the way of headaches. 



Ringing Herbaceous Plants 



"Ringing" is a practice sometimes employed 

 to apparent advantage in vineyards, as by it 

 the bunches of grapes are in some cases made 

 larger and earlier. It seemed feasible to apply 

 the same practice to herbaceous plants, but test 

 made upon tomatoes and chrysanthemums at 

 the experiment station at Geneva, N.Y., proved 

 the theory fallacious. With neither class of 

 plants was there any gain in yield, increase in 

 size or hastening of maturity; but in nearly 

 every case the ringing was detrimental. So 

 marked was the injurious effect in many in- 

 stances, especially upon the root systems of the 

 plans, that the experimenters doubt whether 

 the practice is not more injurious than useful, 

 even upon grape vines where the apparent ad- 

 vantage is most evident. These tests are re- 

 corded in bulletin No. 288 of the station. 



Fertilizing Old Orchards 



Bulletin No. 289, issued by the agricultural 

 experiment station at Geneva, N.Y., teaches 

 some important lessons on orchard fertilizing, 

 as follows: That an orchard soil may not need 

 potash, phosphoric acid, nor lime, even though 

 the soil may have been cropped a half century; 

 that in a soil which produces apples of poor color, 

 potash and phosphoric acid may not improve 

 the color; and that the apple does not seem to 

 be as exhaustive of soil fertility as farm crops. 

 The experiment suggests, as well, that to assume 

 without defmite knowledge that a tree needs 

 this or that plant food often leads to the waste 

 of fertilizing material ; and that in the matter of 

 fertilizing an orchard a fruit grower should e- 

 pcriment for himself, since an orchard's ner 

 fertilizer can be determined only by the !> 

 of the trees when supplied with the sevt 

 foods. 



