i8o 



GARDENING. 



Mar. /, 



Water hides under no disguises; it is 

 alwaj*s separable and recognizable; it 

 does not partake of the mysteries of the 

 food supply. 



The man who undertakes to protect 

 plants from the accidents of outdoor life 

 by housing them under a canopy of glass, 

 becomes the step-parent to nature, and 

 will succeed best when he most fully 

 understands the needs of the charges 

 entrusted to his care. It does not follow 

 that the greenhouse cultivator is to imi- 

 tate nature in her methods of supplying 

 the wants of the plant; more economical, 

 more direct, and more efficient methods 

 are often possible, and in fact are often 

 necessary to secure commercial success. 



Because out of doors it rains on the just 

 and unjust alike is no reason why the 

 florist should drench everything within 

 his houses daily. Overhead watering 

 under glass may be a good imitation of 

 nature, but it is not necessarily the way 

 to bring about the result the florist has 

 in view, healthy plants with a maximum 

 development of flowers. The watering- 

 pot and its substitute, the spray nozzle, 

 are to be considered primitive implements, 

 which are to be laid aside as soon as 

 improved methods can be devised. A 

 move in this direction has been made by 

 carnationists in using a modified nozzle 

 and applying the water to the soil with- 

 out wetting the foliage. 



It is because the carnationists have 

 shown themselves progressive, and will- 

 ing and ready to test promising innova- 

 tions, that I venture to advocate to-day 

 a radical change in watering the green- 

 house, and one that requires some expense 

 to inaugurate. I remember with pleas- 

 ure the reception of my paper before this 

 society at its Buffalo meeting, in which I 

 suggested watering carnations between 

 the rows and keeping the foliage dry as 

 far as practicable. Although the wraith 

 of the red spider seemed to hover over the 

 assembly and threaten grave disaster to 

 such a course, yet the suggestion was 

 tested, approved, and under various mod- 

 ified forms became a part of standard 

 carnation culture. I now come before 

 you to advocate watering the benches 

 from beneath the soil and practical aban- 

 donment of surface watering and spray- 

 ing. It has sometimes been called sub- 

 irrigation, but a better term is sub- 

 watering. 



The essential feature of this method, 

 which was originated at the University 

 of Ohio and has been tested in a number of 





w 



BBNOH ARRANGED FOR SUB-WATERING. 



places for various glass-grown vegetable 

 crops, consists of a water-tight bench 

 with a layer of open material on the bot- 

 tom through which water moves readily, 

 and the filling of the bench completed 

 with soil in the usual manner. The bench 

 is kept moist by supplying water to the 

 porous layer beneath, from which the 

 soil takes it by capillarity. No water is 

 applied directly to the soil, and all use of 

 the nozzle is done away with. Before 

 giving the working details of this method, 

 I wish to call attention to some of the 



reasons why watering plants should be 

 considered a matter of great importance 

 and worthy of the most careful study. 



In the first place every plant, generally 

 speaking, consists of three parts of water 

 to one part of all other kinds of substances. 

 This proportion is quite universal for all 

 living things. It is equally true of trees, 

 grass, mosses and molds. It also holds 

 for animals. A cabbage plant and the 

 body of a dog do not vary much in the 

 proportion of water to solids. 



Immature organs contain more water 

 than when matured. Although the water 

 in a whole carnation plant, roots, stems, 

 leaves and flowers amounts to about 75% 

 of the total weight, yet in the young 

 shoots, such as would be suitable for 

 cuttings, it rises to 907c, and in the 

 half formed leaves is even greater yet. If 

 we remember that thechief growth of the 

 plant takes place in the parts where the 

 largest amount of water occurs, we shaK 

 be l.asonably safe in inferring that water 

 is a very essential factor in growth. 



It has been ascertained, in fact, that 

 the tissues must not only be saturated 

 with water, but they must be super- 

 saturated, that is, contain so much water 

 that every cell is distended with the 

 pressure, before growth will proceed. 

 Each cell must be stretched by the inter- 

 nal pressure of the water, as a toy bal- 

 loon is distended by the air forced into it. 

 It is this by no means inconsiderable 

 tension that renders young parts firm 

 and brittle, and when it is removed they 

 wilt. No appreciable growth can take 

 place in leaves and stems that are wilted, 

 or in a wilted condition. In the carna- 

 tion the cell structure is so compact and 

 the walls so rigid that the loss of water 

 is often very considerable before visible 

 wilting takes place. At this point lies a 

 danger, for the plants maj- sutler for 

 water for some time before the attendant 

 notices their condition. With ideal treat- 

 ment the plants should never wilt, and 

 never lack for water to enable them to 

 grow. 



Not only must a certain amount of 

 water be present in the plant to secure its 

 active development, but a stream of 

 water must be passing through the plant 

 constantly, from the roots to the leaves. 

 This upward flow of water is essential to 

 most plants. It is the means of taking in 

 the various fertilizing materials, or food 

 substances, from the soil and transporting 

 them to the upper parts of the plant, where 

 they enter into the solid structures form- 

 ing the tissues. The root hairs on the 

 fine roots suck in the soil water, and its 

 burden of nutritive material and force it 

 forward into the larger roots and the 

 stem, with pump-like activity, so long as 

 water is available. The leaves dispose of 

 the water by allowing it to escape from 

 their surfaces as an invisible vapor, leav- 

 ing behind all substances held in solution. 

 In some instances the water passes out 

 through any part of the surface, but there 

 are always stomata, minute openings, 

 sometimes called breathing pores, which 

 permit it to escape much more readily. 

 The carnation has the surface of all green 

 parts, both stems and leaves, overspread 

 with a layer of white wax, which is 

 impervious to moisture. All transpira- 

 tion must therefore be through the 

 stomata. These openings are very numer- 

 ous, there being from one to five hundred 

 thousand on every leaf. I'nlike most 

 plants, the carnation shows no material 

 difference in the minute structure of the 

 upper and lower surfaces of the leaves. 

 They contain no spongy tissue, and have 

 the stomata distributed evenly through- 

 out, both above and below. If one 



should look through glasses that magni- 

 fied as much as a common microscope, 

 the leaf would appear to be thickly stud- 

 ded with round openings, like little wells 

 (see fig. 1), and peering into one, some 

 way below the surface would be seen a 

 double valve that automatically opens 

 and closes (see fig. 2), much as the lips 

 open and shut to permit or prevent the 

 passage of substances into the mouth. 



PIGS I AND II. 



These are the guard cells, and when they 

 are shut, little or no moisture can pass 

 out or in. There are two conditions 

 especially under which the stomata are 

 closed; the first is when the plant wilts. 

 This is a fortunate arrangement, for it 

 tends to prevent loss of moisture at a 

 time when the roots for some reason are 

 no longer able to supply the needs of the 

 plant. The second condition closing the 

 stomata, is when water is dashed over 

 the plant. A drop falls into each opening 

 and causes the guard cells to swell until 

 they effectually fill the passage. It mat- 

 ters not how much water the roots are 

 taking in at the time, the whole water 

 system of the plant is clogged and 

 development is retarded. 



Sometimes the movement of water 

 through the plant is stopped, even when 

 the stomata are open; for when the 

 atmosphere is satuated it is evident that 

 evaporation from the plant must neces- 

 sarily come to a standstill. Perfect satura- 

 tion of the atmosphere is probably rare 

 even in a closed greenhouse, but partial 

 saturation must in a measure check the 

 internal water stream, and in so far must 

 be detrimental to the best development 

 of the plant. 



If there is anything that the structure of 

 the carnation plant and the known func- 

 tion of the organs clearly teaches, it is 

 that there should be a never failing sup- 

 ply of moisture for the roots, and a fairly 

 dry atmosphere for the foliage. I venture 

 to say that these conditions can not be 

 better mjt than by sub-watering. The 

 present method of surface watering, even 

 when most skillfully done, probably never 

 gives the plants the full amount of water 

 they would use. The soil is alternately 

 too wet and too dry, and besides often 

 suffers from a lack of water at the bottom 

 of the bench although the surface seems 

 wet enough. The difference between the 

 amount of growth when an ample and 

 constant water supply is provided, and 

 that secured from the usual surface 

 method of watering is always a source of 

 astonishment when fairly tested and the 

 results clearly set forth. I have no data 

 to present in growing carnations by the 

 new method of sub-watering; and will 

 not detain you with figures taken from 



