748 



THE GARDENERS' CHRONICLE OF AMERICA. 



held in check in a fairly dry atmosphere than in one reek- 

 ing with moisture. 



Damping, however, is generally overdone ; but excep- 

 tion might be taken to the above statements regarding 

 the damping of rose, carnation and chrysanthemum 

 houses on very hot, dry days ; since on such days damp- 

 ing has a very beneficial effect, in that, Urst, it cools the 

 air — this cooling is almost independent of the tempera- 

 ture of the water used for damping, the conversion of 

 the liquid into a gas is. that which absorbs the heat of 

 the atmosphere ; and because, in the second place, wlien 

 we moisten the atmosphere on extremely hot days we 

 cut down the transpiration of water through the leaves : 

 a very desirable operation, for when the water-carrying 

 capacity of the roots is unequal to the heavy drafts upon 

 it, wilting (and sometimes burning) results — though the 

 plants be ever so wet at the roots. 



Why is it important to give the right aspect to a green- 

 house, and the correct pitch to the roof? I introduce 

 this subject because it seems to me highly important that 

 everv gardener should have this well fixed in his mind 

 as he may be called upon any time to select a site for a 

 greenhouse, and should he make any great error in this 

 selection and the greenhouse be built, endless trouble and 

 dissatisfaction will result. Generally speaking, the good 

 firms of greenhouse builders will offer valuable sugges- 

 tions as to the site, but, this notwithstanding, every gar- 

 dener should competently inform himself on this im- 

 portant point. Plants that malce their growth between 

 March and November 1 thrive well in houses running 

 north and south and (of course) facing east and west — 

 especiallv if of the span-roof type. Such houses make 

 good graperies, peach and chrysanthemum houses. 



Winter-grown roses and carnations do well in houses 

 running east and west — or, better, with the southerly 

 side facing about twenty degrees east of due south ; this 

 slightly easterly aspect being a very important factor in 

 the work of the rose grower. His houses catch the early 

 morning sunshine: he is--able to dispense with the fire 

 heat sooner; his syringing can be attended to earlier — 

 the plants benefiting by a longer drying period ; and 

 thus he insures and conserves the full photosynthetic vir- 

 tue of the early morning sunshine — which scientists claim 

 to be greater than that of the afternoon. Thus many 

 reasons favor the house with a little east of south aspect. 



We now come to the matter of pitch or slope of the 

 roof. Theoretically, the roof of a greenhouse for the 

 winter growing of plants should be as nearly at a right 

 angle to the sun as is possible during the darkest winter 

 months, say, during November, December and January. 

 Among many practical reasons militating against carry- 

 ing this theory strictly into practice is the one often ad- 

 vanced that the theory necessitates constructing houses too 

 high and too narrow; but. generally speaking, the roof 

 should be as steep as possible, conforming to the general 

 structural requirements. For this latitude a pitch of about 

 thirty-six to forty degrees is a very good one. The 

 steeper the roof the greater the amount of light \yhich 

 reaches the plants. As we go north a steeper roof is re- 

 quired than would be needed at a point further south in 

 order to obtain the same amount of light. A very good 

 feature of steep roofs is the facility with which they shed 

 the snow in winter — especially where there are no gut- 

 ters on the house. 



Why are two-inch wrought iron heating pipes to be 

 preferred to four-inch ca.st iron ones for heating green- 

 houses with hot water? Because in any given number of 

 feet of radiating surface we have only half the quantitv 

 of water to heat — this means more rapid' circulation and 

 economy. The two-inch pipe takes up less space, can 

 be easily removed and repaired, offers the advantages of 



standard threads and fittings. The cast iron, it is true, 

 offers greater resistance to corrosion and will generally 

 last longer than the wrought iron. 



Why is it more important to keep uniform tempera- 

 tures at night than during the day? I conceive this to 

 be a question seldom asked and, perhaps, seldomer an- 

 swered. Experience shows night temperatures are the 

 best which keep the plants as inactive as possible during 

 darkness without checking the growth too much. The 

 optimum temperature being given for any kind of plant, 

 let us consider the result of deviation in either direction, 

 up or down. Take a rose, for instance, of some variety 

 whose optimum temperature is 58, and suppose the night 

 temperature to be allowed to fall to 54 or 55 for any 

 length of time, what will be the result? We will find 

 shorter stems, fewer flowers, and — if it. is at the critical 

 period in the fall of the year — some varieties will go to 

 sleep, taking a month or two to awaken. On the other 

 hand, suppose the temperature be allowed to run up to 

 62 or 63 — we will have longer but weaker stems and 

 flowers of poorer keeping quality. Besides, the forcing- 

 process decreases the resistance of the plant to the at- 

 tacks of insect and disease. The ill effects are likely to 

 be more pronounced when the temperature see-saws up 

 and down — high one night and low the next — and it 

 might be advanced as an axiom that the ill effect is com- 

 mensurate to the amount of deviation from the correct 

 temperature. 



It has ever been my expereince that, other things being 

 equal, the best stock was grown where correct night tem- 

 peratures were kept. Strictly uniform day temperature 

 is not so important because, in the main, variations are 

 caused bv the sun, and if the heat runs up in bright sun- 

 shine causing more rapid growth, so likewise the sun's 

 power to keep pace with the heat is greater, the function 

 of the plant leaves to develop their elaborate chemical 

 processes is facilitated, and quality as well as quantity of 

 grows is assured. 



Why does a plant appear to draw towards the light 

 when set near the window? It is because light retards 

 growth. The portion of the stem further from the light 

 over-grows — i. e., grows faster than — the portion of the 

 stem directly exposed to and facing the light; hence the 

 marked inclination of the plant to the light. 



Why do we feed plants? Air and water, of course, 

 are the two greatest factors in plant growth, but the term 

 feeding the plant refers, perhaps technically, to supplying 

 the mineral salts in which the soil appears to be deficient. 

 We feed nitrogenous substances to promote and increase 

 growth ; phosphatic substances for fruitfulness and early 

 maturity, and potash for quality — such as high color and 

 flavor in fruits, scent in flowers, etc. Every user of fer- 

 tilizer should familiarize himself with its chemical prop- 

 erties, ingredients and virtues; adapting the particular 

 fertilizer to the result desired, and should possess a 

 cogent concept of just what he is feeding for. If T may 

 use the term, he should function chemically, and strive 

 for technique. 



Why do we spray orchard and other trees? To keep 

 insects and fungoid diseases in check, to promote and 

 enhance the vigor of our trees and the quality of the 

 fruit. Copper sulphate in the form of Bordeaux mixture 

 is generally used for fungoid diseases ; arsenate of lead 

 for leaf-eating worms and insects, and lime sulphur or 

 crude oil spray for scale and sucking parasites. 



Why do we prune? Some do not; others prune spar- 

 ingly. To prune intelligently a clear idea of the objects 

 nf pruning is essential. To thin out the weak and super- 

 fluous growths, thus conserving maximum light and air, 

 and assuring further fruitful, strong and healthy growth ; 



