GREENHOUSE 



among amateurs. The Iiousewife is always asking how 

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

 would bloora 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 

 effort if we know the natural season of the plant. N early 

 all Greenhouse plants are grown on this principle. We 

 give them conditions as nearly normal to them as pos- 

 sible. We 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 Foreinfi). But these forcing plants are 

 few compared with tlio wlmlf number of Greenhouse 

 species. The season n|- normal ;u'tivityis the key to the 

 whole problem of grow in- phdiis under glass ; yet many 

 a young man has scrvid .in apprenticeship, or has taken 

 a course in an agricultural college, without learning this 

 principle. 



The second principle from the plant side is this: The 

 greater part of the (/roirfh should be mnCe before the 

 plant is expected to h/<">iii. It is natural for aplant first 

 to grow: then it bI<M.nis and makes its fruit. In the 

 great majority of casts, tlirsr two great functions do 

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

 gree. This principle is admirably illustrated in woody 

 plants. The gardener always impresses upon the ap- 

 prentice the necessity of securing" well ripened woud "of 

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

 flowers. That is, the plant should have completed one 

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

 ture and sappy wood only poor bloom may be expected. 

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

 The vegetative stage or cycle may be made shorter or 

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

 growth 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 bhjoming stage. 



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

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

 duces fruitfuhiess or fiorifivoitsnfss. 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 confined, and the plant is set 

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

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

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

 grower or the cucumber-grower wants a shallow bench, 

 that the plants may not run too much to vine. 



Most plants demand a /mrfirnlar season of ivactirity 

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

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



GREENHOUSE 



695 



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 

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

 —of which some of 

 the Cape bulbs, as 

 Nerines, are exam- 

 ples — rest in our 

 summer and bloom 

 in fall. 



species 



1003. Violet house w^ith water heating. 



plants have been forced to cease their activities because 

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

 must be humored when they are grown under glass. 

 Some plants have no such definite seasons, and will grow 

 more or less continuously, but these are the exceptions. 

 Others may rest at almost any time of the year; but most 

 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; but bulbs and tubers and 



1004. Rose house. 150x20 ft., piped for steam. 



The natural habitat of the plant is significant to the 

 cultivator: it gives a suggestion of the treatment under 

 which the plant will be likely 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, but where they 

 must. Many 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 Dipladenia 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 pepino warm, because it is Central and 

 South American. Ixia is generally regarded in the 

 North as only a glasshouse subject because it is a Cape 

 bulb, yet it thrives in the open in parts of New England, 

 when well covered during winter. 



The best method of propagation is to be determined for 

 as a rule, quicker results and 

 stockier plants are obtained from 

 cuttings than from seeds. Of neces- 

 sity, most Greenhouse plants are 

 grown from cuttings. In the great 

 majority of cases, the best material 

 for cuttings is the nearly ripe wood. 

 In woody plants, as Camellias and 

 (jthers, the cutting material often 

 may be 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 Impatiens Sultani. 



Coming, now, to some of the ]>rinciples which underlie 

 the proper management of the bouse, 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. 



