696 



GREENHOUSE 



GREENS 



As a rule, the night temperature should be 10-15 Falir. 

 below the maximum day temperature in the shade. A 

 high night temperature makes the plants soft and tends 

 to bring them to maturity too early. It makes weak 

 stems and flabby flowers. The temperature should 

 change gradually: violent fluctuations are fatal to good 

 results, particularly to plants which are grown at a high 

 temperature. 



In Greenhouse cultivation, every plant is to receive in- 

 dividual care. In the field, the crop is the unit: there 

 we deal with plants in the aggregate. In the Green- 

 house, each plant is to be saved and to receive special 

 care: upon this success depends. There should be no 

 vacant places on the Greenhouse bench; room is too 



1005. Range of modern commercial Greenhouses. 



valuable. All this means that every care should be taken 

 to so arrange the house that every plant will have a 

 chance to develop to its utmost perfection. Patient 

 hand labor pays with Greenhouse plants. The work can- 

 not be done by tools or by proxy. Therefore, the gar- 

 dener becomes skilful. 



Every caution should be taken to prevent the plants 

 from becoming diseased or from being attacked by in- 

 sects. The greater part of insect and' fungous troubles 

 in the Greenhouse are the result of carelessness or of 

 mistakes in the growing of the plants. Determine what 

 diseases or pests are likely to attack any plant; dis- 

 cover under what conditions these diseases or pests are 

 likely to thrive: then see that those conditions do not 

 arise. Keep the house sweet and clean. Destroy the af- 

 fected parts whenever practicable. Then if trouble come, 

 apply the fungicide or the insecticide. Remember that the 

 very protection which is given the plants, in the way of 

 equable conditions, also protects their enemies : there- 

 fore, it is better to count on not having the difficulties 

 than on curing them. If diseases or pests have been 

 troublesome, make a complete change of soil or stock 

 before the next season, if practicable. At least once 

 every year there is an opportunity to rid the place of 

 pests. Many gardeners carry their troubles year by 

 year by trying to fight them, when they might succeed 

 by trying to avoid them. 



The higher the temperature and the more rapid the 

 growth, the greater the care necessary to insure good re- 

 sults. Plants grown under such conditions are soft and 

 juicy. They are easily injured by every untoward cir- 

 cumstance, particularly by drafts of cold air. Let a 

 draft of cold air fall on cucumbers or rapid- growing 

 roses, and mildew will result in spite of Bordeaux mix- 

 ture and brimstone. 



In dark weather, grow the plants slow. If given too 

 much heat or too much water, they become soft and 

 flabby, and fall prey to mildew, green fly and other dis- 

 orders. A stocky plant is always desirable, but particu- 

 larly in the dull weather and short days of midwinter: 

 at that time, take extra precautions in the management 

 of the house. 



Watering plants under glass requires more judgment 

 than any other single operation. Apply water when the 

 plants need it, is a gardener's rule, but it is difficult to 

 apply because one may not know when they need it. 

 Yet, if the gardener will put the emphasis on the word 

 need he will at least be cautioned; novices often apply 

 the advice as if it read, Apply water when the plants 

 will stand it. Water thoroughly at each application. 

 Mere dribbling may do more' harm than good. Many 

 people water too frequently but not enough. Remember 

 that in benches evaporation takes place from both top 



and bottom of the soil; and in pots it takes place from 

 all sides. Water on a rising temperature. This advice 

 is particularly applicable to warrnhouse stuff. Watering 

 is a cooling process. The foliage should not go into the 

 night wet, particularly if the plant is soft-growing or is 

 a warmhouse subject. Water sparingly or not at all when 

 evaporation is slight, as in dull weather. 



In all Greenhouse work, see that the soil is thoroughly 

 comminuted and that it contains much sand or fiber. 

 The amount of soil is small: see that it is all usable. 

 In the garden, roots may wander if good soil is not at 

 hand: in pots they cannot. The excessive watering in 

 Greenhouses tends to pack the soil, particularly if the 

 water is applied from a hose. The soil tends to run to- 

 gether or to puddle. Therefore, it should con- 

 tain Tittle silt or clay. The gardener's prac- 

 tice of adding sand to his Greenhouse soil is 

 thus explained. 



Ventilation is employed for the purpose of 

 reducing temperature and of lessening atmos- 

 pheric moisture. Theoretically, it is employed 

 also for the purpose of introducing chemically 

 fresh air, but with the opening and shutting 

 of doors, and the unavoidable leaks in the 

 house, it is not necessary to give much thought 

 to the introduction of mere fresh air. Venti- 

 lating reduces the temperature by letting out 

 ., warm air and letting in cool air. The air 

 should be admitted in small quantities and at 

 the greatest distance from the plants in order 

 to avoid the ill effects of drafts on the plants. Many 

 small openings are better than a few large ones. Venti- 

 late on a rising temperature. 



Most plants require shading in the summer under 

 glass. Shading is of use in mitigating the heat more 

 than in tempering the light. A shaded house has more 

 uniform conditions of temperature and moisture. If 

 plants are grown soft and in partial shade, they are 

 likely to be injured if exposed to bright sunlight. Sun- 

 scalding is most common in spring, since the plants are 

 not yet inured to bright sunshine and strong sun heat. 

 The burning of plants is due to waves (not bubbles) in 

 the glass. It should be said that, other things being 

 equal, the larger the house the easier is the manage- 

 ment of it. It is less subject to fluctuations of tempera- 

 ture and moisture. In the "nesting" of houses, one 

 house protects the other from the weather. A good 

 commercial American Greenhouse plant is shown in 

 Fi S- ] 005. L . H . B. 



GEEENS, CHRISTMAS. The Christmas Greens in- 

 dustry has developed to an enormous -extent within a 

 few years. Some twenty years ago, when florists began 

 to use lycopodium, a dozen barrels were all that was 

 used in a single season in many of our lower cities. 

 To-day the output in the United States is probably 

 nearly 200 tons about 40 car loads. 



The materials now used, mentioned in something like 

 their order of commercial importance, are holly, lyco- 

 podium (also known as bouquet green, ground pine, 

 club moss, etc.), mistletoe, laurel, and cedar clippings. 

 Other articles of similar utility are wild smilax, hardy 

 ferns, needle pines, outdoor palm leaves, Florida moss, 

 galax leaves and leucothoe sprays : these all come 

 from the South. 



Lycopodium is one of the oldest and commonest of 

 decorative materials. During seasons of long con- 

 tinued "Indian summer," a surplus is frequently gath- 

 ered by careless pickers and dumped on the market. 

 The choicest picked stock being obtainable only through 

 the regular and well established trade channels, such 

 sources are usually the only ones in case of early snow 

 storms, which prevent the gathering of it. Choice 

 stock from eastern Vermont, northern New York and 

 Pennsylvania has been usually handled in large sugar 

 barrels, tied in carefully arranged bunches, weighing 

 perhaps one-half to one pound each. These bunches are 

 packed in the barrels in layers, with roots toward the 

 center. The quantity is always limited and the price 

 25 to 35 per cent higher than the Wisconsin and Michi- 

 gan stock. Lycopodium, as handled in the West, comes 

 almost entirely from northern Wisconsin, and is ga iU 

 ered from the north end of Lake Michigan, in the 



