GREENHOUSE 



GREENHOUSE 



695 



among amateurs. The housewife is always asking how 

 to make her wax-plant bloom, without knowing that it 

 would bloom if she would let it alone in winter and let 

 it grow in spring and summer. What we try to accom- 

 plish by means of fertilizers, forcing and other special 

 practices may often be accomplished almost without 

 ftfort if we know the natural season of the x>lant. Nearly 

 all Greenhouse plants are grown on this principle. We 

 give them conditions as nearly normal to them as pos- 

 sible. Wc endeavor to accommodate our conditions to 

 the plant, not our plant to the conditions. There are 

 some plants which it is possible to make bloom in ab- 

 normal seasons, as roses, carnations, lilies : these we 

 may force (see Forcing). But these forcing plants are 

 few comv»ared with the whole number of Orccnhouse 

 species. The season of normal activity is the key to the 

 whole problem of growing plants under glass ; yet many 

 a young man has served an apprenticeship, or has taken 

 a course in an agricultural college, without learning this 

 principle. 



The second principle from the plant side is this: 'Flic 

 (/renter part of the growth i^houtd be DuuZe before the 

 plant is expected to bloom. It is natural for a plant lirst 

 to grow: then it hUxjms and makes its fruit. In the 

 great majority of cases, these two great functions do 

 not proceed simultaneously, at least not to their full de- 

 gree. This principle is admirably ilhistrated in woody 

 plants. The gardener always inijin-sses upon the ap- 

 prentice the necessity of securing*' wtdl ripened wood "of 

 Azaleas, Camellias, and the like, if he would have good 

 tiowers. That is, the plant should have completed one 

 cycle of its life before it begins another. From imma- 

 ture and sappy wood only poor l)loom may l)e expected. 

 This is true to a large degree even in herljarHiins plants. 

 The vegetative stage or cycle may be made shorter or 

 longer by smaller or larger pots, but the stage of ranid 

 tjrowth must be well passed before the best bloom is 

 wanted. Fertilizer applied then will go to the pro- 

 duction of flowers ; but before that time it will go to 

 the production of leaf and wood. The stronger and bet- 

 ter the plant in its vegetative stage, the more satisfac- 

 tory it will be in its blooming stage. 



Closely like to the last principle is the law that elierk- 

 ing growth^ so long as the plant remains healthi/, in- 

 duces frnilfulness or florift'ronsiiess. If the gardener 

 continues to shift his plants into larger pots, he should 

 not expect the best results in bloom. He shifts from 

 pot to pot until the plant reaches the desired size; then 

 he allows the roots to be contiued. and the plant is set 

 into bloom Over-potting is a serious evil. When the 

 blooming habit is once begun, he may ajiply liquid ma- 

 nure or other fertilizer if the plant needs ir. The rose- 

 grower or the cucumber-grower wants a shallow bench, 

 that the plants may not run too much to vine. 



Most pJa})fs demand a paiiicidar season of inactivity 

 or rest. It is not rest in the sense of recuperation, but 

 it ia the habit or custom of the plant. For ages, most 



thick rhizomes always signify that the plant was obliged, 

 in its native haunts, to carry itself over an unpropitious 

 season, and that a rest is very necessary, if not abso- 

 lutely essential, under domestication. Instinctively, we 

 let bulbous plants rest. They usually rest in our winter 

 aTid bloom in our spring and summer, but some of them 

 — of which some of 

 the Cape bulbs, 

 Nerines, are exa 

 pies — rest in c 

 s u m m e r a n d b 1 o < 

 in fa 



1003. Violet house with water heating. 



plants have been forced to cease their activities because 

 of cold or dry. These habits are so tixed that the plants 

 must he humored when they are grown under glass. 

 Some plants have no such definite season'^, and will grow 

 more or less continuously, but these are the exceptions. 

 Others may rest at almost any time of the year; butmost 

 plants have a definite season, and this season must be 

 learned. In general, experience is the only guide as to 

 whether a plant needs rest; hut bulbs and tubers and 



100-4. Rose house, 150x20 ft., piped for stea 



Tlie naturnt habitat of the plant is significant to the 

 culfirator: it gives a suggestion of the treatment undtr 

 u'hich the plant will be likehf to thrive. Unconsciously 

 the plant-grower strives to imitate what he conceives to 

 be the conditions, as to temperature, moisture and sun- 

 light, under which the species grows in the wild. 

 We have our tropical, temperate and cool houses. Yet, 

 it must be remembered that the mere geography of a 

 plant's native place does not always indicate what the 

 precise nature of that place is. The plant in question 

 may grow in some unusual site or exposure in its native 

 wil Is. In a general way, we expect that a plant com- 

 ing from the Amazon needs a hothouse; but the details 

 of altitude, exposure, moisture and sunlight must be 

 learned by experience. Again, it is to be said that plants 

 do not always grow where they would, hut where they 

 must. iMany plants which inhabit swamps thrive well 

 on dry lands. 



The upshot of all this is, that the habitat and the 

 zone give the hint : with this beginning, work out the 

 proper treatment. Examples are many in which culti- 

 vators have slavishly followed the suggestion given by 

 a plant's nativity, only to meet with partial failure. Be- 

 cause the Dipladf-nia" is Brazilian, it is generally sup- 

 posed that it needs a hothouse, but it gives best results 

 in a coolhouse. Persons often make a similar mistake 

 in growing the pcpino warm, because it is Central and 

 South American. Ixia is generally regarded in the 

 North as only a glasshouse subject because it is a Capo 

 bnlb. yet it thrives in the open in parts of New England, 

 when well covereil during winter. 



The best method of j>rnpagat>on is to be determined for 

 but, as a rule, qtUcker results and 

 storkicr phnits are obtained from 

 cuttings than from seeds. Of neces- 

 sity, most Greenhtjuse plants are 

 LT'>wn from cuttings. In the great 

 majority of cases, the best material 

 fur cuttings is the nearly ripe wood. 

 In woody plants, as Camellias and 

 orhers, the cutting material often 

 mav he completely woody. In 

 herbaceous plants, the proper ma- 

 terial is stems which have begun 

 to harden. Now and then better 

 results are secured from seeds, even with perennials, 

 as in Grevillea and Impatien.'s Sultani. 



Coming, now, to some of the principles which underlie 

 the proper management of the house, it may be said, 

 first of all, that the grower should attempt to imitate a 

 ■natural day. There should be the full complement of 

 continuous sunlight ; there should be periodicity in 

 temperature. From the lowest temperature before 

 dawn, there should be a gradual rise to midday or later. 



