540 



The Weekly Florists^ Review* 



FEBRUARY 24, 1S9S. 



be consiilered primitive implemeuts, 

 which ai'c to be laid aside as soon as 

 improved methods can be devised. A 

 move ill tli:s direction has been madt' 

 by carnationists in using a modified 

 nozzle and applying the water to the 

 soil without wetting the foliage. 



It is because the carnationists have 

 shown themselves progressive, and 

 willing and ready to test promising in- 

 novations, that I venture to advocate 

 to-dav a radical change in watering the 

 greenhouse, and one that requires 

 some expense to inaugurate. I remem- 

 ber with pleasure the reception of my 

 paper before this society at its Buffalo 

 meeting, in which I suggested water- 

 ing carnations between the rows and 

 keeping the foliage dry as far as prac- 

 ticaljle,. Although the wraith of the 

 red spider seemed to hover over the 

 assembly and threaten grave disaster 

 to such a course, yet th? suggestion 

 was tested, approved, and under vari- 

 ous modified forms became a part of 

 standard carnation culture, I now- 

 come before you to advocate watering 

 the benches from beneath the soil and 

 practical abandonment of surface 

 watering and spraying. It is some- 

 times called sub-irrigation, but a bet- 

 ter term is sub-watering. 



The essential feature of ths meth- 

 od, which was originated at the I ni- 

 vei'sity of Ohio, and has been tested in 

 a n amber of p'aces for various gla.5S- 

 grown vegetable crops, consists of a 

 water tight bench with a layer of opjn 

 material on the bottom 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 ap- 

 plied directly to the soil, and all use 

 of the nozzle is done away with. Be- 

 fore giving the working details of tnis 

 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, gen- 

 erally 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, grassiS, 

 mosses and mou'ds. 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 per cent of the 

 total weight, yet in the young shoots, 

 such as would be suitable for cuttings, 

 it rises to 90 per cent, and in the half- 

 formed leaves is even greater yet. If 

 we remember that the chief growth of 

 the plant takes place in the parts 

 where the largest amount of water oc- 

 curs, we shall be reasonably safe in in- 

 ferring 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 witn 

 the pressure — before growth will pro- 

 ceed. Each cell must be stretched by 

 the internal pressure of the water, as 

 a toy balloon 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 appreci- 

 able growth can take place in leaves 

 and stems that are wilted, or in a 

 wilted condition. In the carnation the 

 cell structure is so compact and the 

 walls so rigid that the loss of water 

 is often very considerable before vis- 

 ible wilting takes place. At this point 

 lies a danger, for the p'ants may suf- 

 fer for water for some time before the 

 attendant notices their condition. With 

 ideal treatment 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 se- 

 cure its active development, but a 

 stream of water must be passing 

 through the plant constantly, from th3 

 roots to the leaves. This upward flow 

 of water is essential to most plants. 

 It is the means of taking in the vari- 

 ous fertilizing materials, or food sub 

 stances, from the soil, and transport- 

 ing them to the upper parts of the 

 plant, where they enter into the solid 

 structures forming the tissues. The 

 root hairs on the fine roots suck in the 

 soil water and its burden of nutritive 

 material and foi'ce it forward into tli^ 

 larger roots and the stem with pump- 

 like activity, so long as the water is 

 available. The leaves dispose of the 

 water by allowing it to escape from 

 their surfaces as an invisible vapor, 

 leaving behind all substances held in 

 solution. 



In some instances the water passss 

 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 transpiration must 

 therefore be through the stomata. 

 These openings are very numerous, 

 there being from 100.000 to 500,000 

 on every leaf. Unlike 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 throughout, 

 both above and below. If one should 

 look through g'asses that magnified as 

 much as a common microscope, the 

 leaf would appear to be thickly stud- 

 ded with round openings, like little 

 wells, and peering into one, some 

 ways below the surface would be seen 

 a double valve that automatically 

 opens and closes, much as the lids 

 open and shut to permit or prevent the 



passage of substances into the mouth. 

 These are the guard cells, and when 

 they are shut, little or no moisture can 

 pass out or in. There are two condi- 

 tions especially under which the sto- 

 mata are closed; the first is when the 

 plant wilts. This is a fortunate ar- 

 rangement, 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 matters not how much water the 

 roots are taking in at the time — the 

 whole water system of the pant is 

 clogged, and development is retarded. 



Sometimes the movement of water 

 through the plant is stopped evea 

 when the stomata are open; for whe'a 

 the atmosphere is saturated it is evi- 

 dent that evaporation from the plant 

 must necessarily come to a standstill. 

 Perfect saturation of the atmosphere is 

 probably rare, even in a closed green- 

 house, but partial saturation must in 

 a measure check the internal water 

 stream, and in so far must be detri- 

 mental to the best development of the 

 plant. 



If there is anything that the struc- 

 ture of the carnation plant and tne 

 known functions of the organs clearly 

 teaches, it is that there should be a 

 never failing supply of moisture foi 

 the roots and a fairly dry atmosphere 

 for the foliage. I venture to say that 

 these conditions cannot be better met. 

 than by sub-watering. The present 

 method of surface watering, even when 

 most skillfully done, probably never 

 gives the plants the full amount of 

 w^ater they would use. The soil is al- 

 ternately too wet and too dry, and be- 

 sides often suffers from a lack of 

 water at the bottom of the bench, al- 

 though the surface seems wit enough. 

 The difference between the amount oC 

 growth when an ample and constant 

 water supply is provided, and that se- 

 cured from the usu'al surface method 

 of watering, is always a source of as- 

 tonishment when fairly tested, and 

 the results clearly set forth. I have no 

 data to present in growing carnations,, 

 by the new method of sub-water. ng,. 

 and will not detain you with figures 

 taken from crops of vegetab'es. but 

 that the carnation will respond to this, 

 method, as have other plants, there 

 can be no doubt. 



One other point needs mention in 

 this connection. The physical charac- 

 ter of the soil has much to do with 

 successful cultivation. Some writers, 

 maintain that it is quite as important 

 an item as the food supply. With sub- 

 watering, the soil remains light and 

 friable, readily permeated with oxy- 

 gen from the atmosphere, easily pene- 

 trated by roots, and at all times in 

 the best of condition for serving the 

 plant. The soil of the bench once- 

 suitably prepared for the reception o[ 

 the plant remains so. or even improves; 



