April 7, 1906 



HORTICULTURE 



447 



SOLUBLE FERTILIZERS. 



Paper read before the American Rose So- 

 ciety, 23d March, 1906, at Boston, 

 By Dudley Malcolm Pray. 



About three-quarters of a century 

 ago a great deal of the mystery of 

 chemistry was cleared away by the 

 discovery that a certain chemical sub- 

 stance (urea) could be made in the 

 chemist's laboratory. Up to that time 

 it had been supposed that this and 

 similar substances could be made in 

 one way only, by obscure processes 

 in the living animal. The fact that 

 such substances could be made from 

 dead things, as it were, and yet be an 

 exact counterpart of those eliminated 

 from living animals caused a profound 

 revolution of thought. Since that 

 time such progress has been made 

 that today we all but make living 

 things from inanimate matter by 

 chemicals, if you will. 



It seems to me that a similar office 

 for horticulture has been performed 

 by those who fifty years ago first 

 brought plants to maturity without 

 soil, by the so-called water culture. 

 In this method, after the seed was 

 sprouted, and when it had a few roots 

 it was supported upright by a split 

 cork or convenient holder over water 

 into which its roots hung, which con- 

 tained minute amounts of plant food 

 in solution. In this way buckwheat, 

 corn and oats were brought to ma- 

 turity. This method of growing plants 

 eliminates the soil, thus simplifying 

 the whole question of essential and 

 non-essential root-foods in plant life. 

 The essentials are found to be seven 

 elementary substances, nitrogen, phos- 

 phorus, potash, lime, chlorine, iron 

 and sulphur, and the non-essentials are 

 soda, magnesium and silica and many 

 others. Of the essentials only nitro- 

 gen, potash, phosphorus and lime need 

 concern us, as there is usually enough 

 of chlorine, iron and sulphur in most 

 soils. Lime is found in sufficient 

 amounts in many soils, but is some- 

 times added to sweeten the soil, i. e., 

 to correct acidity, which may be 

 caused by excessive moisture or acid 

 fertilizers. As a matter of fact, we 

 are concerned mainly with the three 

 remaining essentials of plant life, ab- 

 sorbed through the roots, nitrogen, 

 phosphorus and potash, for these are 

 needed in large amounts and must be 

 supplied continuously to the plant. A 

 fertilizer having these three ingredi- 

 ents is termed complete. 



Not only have these facts been 

 learned from water culture, but that 

 also extremely small amounts of food, 

 even two parts in one thousand, will 

 abundantly sustain active life. To 

 bear this out, we could mention or- 

 chids which are fed daily with very 

 dilute solutions whenever watered, 

 and occasionally with a complete 

 soluble fertilizer called Cookson's 

 formula from its originator. This 

 chemical has demonstrated its value 

 for years, and is commonly used one 

 part in ten thousand parts of water. 

 Note the extreme dilution. 



The source of nitrogen blood, tank- 

 age, guano, all sorts of animal 

 manures, and various commercial fer- 

 tilizers are used. Soluble sources, 

 nitrate of soda, liquid ammonia and 

 ammonia salts, as ammonia sulphate, 

 and phosphate. For rose culture, 

 stable or cow manure is often used, 

 and sometimes nitrate of soda, of 



which we shall speak later. Green 

 manuring is sometimes used. 



For phosphates the animal manures 

 are largely used, also bone, whose 

 phosphate of lime is very slowly given 

 up; in fact, bone-meal requires years 

 to obtain its full value. Super-phos- 

 phates are much used out of doors, 

 but not much under glass, and not 

 being soluble are not adapted to use 

 in watering. None of these above 

 mentioned are soluble or at once 

 available. In certain stages of plant 

 life the energy of the plant seems di- 

 rected into the channels of blossoms 

 rather than foliage. At this time 

 phosphates and potash are demanded 

 much more than nitrogen. The chem- 

 ical, phosphate of potash, has fifty per 

 cent, phosphoric acid and thirty-three 

 per cent, of potash, and dissolved in 

 water. Such feeding should give the 

 needed incentive for blooming, and 

 support well the blooms. 



For potash, we have the animal 

 manures from which it can be obtained 

 quite easily, and wood ashes. As 

 chemicals, there are the sulphate, 

 muriate and carbonate. These chem- 

 icals are used out of doors mostly, but 

 in doors there are often serious ob- 

 jections to their use. 



D. M. Pray. 



About a generation ago, commercial 

 fertilizers came into use. They were 

 more portable and durable than ani- 

 mal manures, and answer for farming. 

 Composed of insoluble materials, as 

 blood, ground or dissolved bone, tank- 

 age, and usually with some cheap 

 soluble chemical of the list already 

 mentioned. They are not very satis- 

 factory for rose culture even outside. 

 Their variable composition, insolu- 

 bility for tank use, often harmful in- 

 gredients, and low food value render 

 them undesirable for bench work. 

 Averaging perhaps fifteen per cent, 

 total plant foods, with three-quarters 

 useless "filler," they yet mark a dis- 

 tinct step towards an ideal soluble 

 fertilizer, and away from the old dis- 

 agreeable manures. 



Rose soil under glass is often mixed 

 with bone and dung (with the latter's 

 numerous living retinue), and some- 

 times lime. But to grow large fine 

 roses and many of them resort must 

 be had to feeding, especially in the 

 height of the season. While top- 

 dressing can be done by hand, the use 

 of the watering equipment to apply 

 soluble food is of great advantage and 

 fast coming into use. For this purpose 

 manure tanks of wood or concrete are 



much used, and the manure is dumped 

 into the water, and generally strained 

 before going into the water system. 

 This simple method gets much of the 

 potash out, but a great deal of the val- 

 uable nitrogen and the phosphates 

 must stay behind, not being dissolved 

 in water. 



An important question to every 

 grower using such tanks is: "How 

 much plant food is there in my tank 

 water?" A chemical analysis will be 

 of some use, but such analyses must 

 be made often. As ordinary stable 

 manure may be considered to have ten 

 pounds of nitrogen and potash each, 

 and less than seven pounds of phos- 

 phate per ton, and so much labor is 

 involved, the actual cost of this plant 

 food is much greater than is suspected 

 by the grower. While these figures 

 are general, they give an idea of some 

 value as to what may be expected. By 

 poor treatment one-half the nitrogen 

 may be lost, thus losing a third of the 

 value of the whole. If no urine is 

 present it has only half the value of 

 one composed of both solid and liquid 

 ingredients. Exposure may have 

 leached much of the value of the 

 manure away without the knowledge 

 of the grower. To get one pound of 

 plant food for one hundred pounds of 

 manure put into the tank is almost 

 beyond hope. 



We wish to point out the great val- 

 ue of soluble fertilizers in tank water. 

 Without repeated chemical analyses, 

 next to nothing is known of the water 

 except by the appearance of plants 

 days afterwards, and even if every- 

 thing goes swimmingly, it is doubtful 

 if the same treatment could be dupli- 

 cated. Even with chemical analyses 

 the situation is only a little clearer, 

 for liquid manure water is not avail- 

 able at once, and much depends upon 

 the soil, the condition of which we 

 are not always certain about. By the 

 use of soluble fertilizers the amount 

 of food applied to any one bench can 

 be known to a dot. For example, we 

 wish to water benches with one hun- 

 dred gallons of water and two pounds 

 of food. We put the food in a bucket, 

 see that it is completely dissolved, 

 then throw it into the tank. To save 

 time and bother, we have made out a 

 little cardboard schedule with parallel 

 columns showing respectively depths 

 if inches in the tank, gallons of water, 

 and finally figures showing in pounds 

 and ounces the proper amounts of 

 plant foods to use for various pur- 

 poses. Or soluble fertilizers may be 

 used in conjunction with the usual 

 manure water. A measuring stick 

 with light scores made at convenient 

 distances is useful in ascertaining the 

 exact amount of liquid in the tank. 

 If the tank has a dead space, so that 

 liquid always remains here, a blank 

 space should be on this measuring 

 stick, and in this way too much fer- 

 tilizer for the amount of water will 

 not be added. The grower now knows 

 exactly what he is doing, which is a 

 rather new thing. We think that 

 while many growers would like to use 

 soluble fertilizer more or less, they 

 do not know just how to begin with 

 absolute safety. They must first have 

 some clear idea of what they are now 

 doing before they can expect to dupli- 

 cate plant foods with an immediately 

 available fertilizer. They should con- 

 sult with chemists interested in soluble 

 fertilizers who could materially assist 



