August, 1910 



THE GARDEN MAGAZINE 



23 



blossoming period should be fed with liquid 

 manure. Plant 6x6 in., in rich soil, not less 

 than seven inches deep. Give them a night 

 temperature from 40 to 55 degrees. Pansies 

 require a very rich, sandy loam — it cannot 

 be made any too rich — and an abundance 

 of water during the growing season. 



Based on thirty-eight years of experience, 

 I think the two best strains of pansies, 

 either for commercial use or for gardens, 

 are as follows: 



For forcing during winter in a violet-house 



or for exhibition I)ed: Vilmorin Boulogne 

 Giant Five Blotched excels all other strains. 

 It is of robust constitution and free flowering. 

 The flowers, of the most vivid colors that 

 exist in pansies, and measure two and 

 three-quarter inches across, carried erect 

 above the foliage on heavy stems seven inches 

 in length. This strain will blossom thirteen 

 weeks after sowing, and can be wintered in 

 a frame with the protection of cotton cloth. 

 For hardiness, freedom of bloom, compact 

 and robust growth, the Peerless Hybrid 



Giant of Switzerland is well named. The 

 flowers have a wide range of colors, a large 

 percentage are marked with three and five 

 blotches; they measure three inches across, 

 and are gracefully carried above the foliage 

 on heavy, stiff stems six inches in length. 

 This strain will stand a temperature of 20 

 degrees below zero without any protection, 

 although a light covering will be beneficial 

 to keep the ground from freezing and thaw- 

 ing. The plants will blossom twelve weeks 

 after sowing. 



The "Acid Soil" Bugaboo!— By j. A. Bonsteel, ^r 



reau ot Soils, U. S. 

 pt. of Agriculture 



NEW LIGHT ON AN OLD FALLACY THAT WORRIES THE GARDENER WITHOUT REASON 



THE statement has been frequently made, 

 both orally and in print, that the gar- 

 dener, farmer, or the teacher in a rural school 

 should" get a Httle litmus paper and test the 

 soil for acidity." This advice has been given 

 by so many people whose authority upon 

 other lines than soil investigation is unim- 

 peachable that it is necessary to call some 

 attention to the limitations and deficiencies 

 of such a test. In the first place, acidity 

 is not necessarily harmful; indeed, an "acid 

 condition of the soil" is beneficial to certain 

 crops; second, acidity of the soil is of no 

 material influence on the majority of other 

 crops; and, third, it is definitely harmful 

 only to one great group, the legumes. 



Soils declared to be "acid" by the major- 

 ity of "testers" are distinctly favorable to the 

 production of Irish potatoes of the highest 

 quality and in good quantity. Many 

 grasses, like timothy, red-top, brome-grass, 

 and the fescues, thrive in an acid soil. Even 

 Kentucky blue grass will do well upon soils 

 which are not distinctly alkaline. 



One fact is incontestable, however, that the 

 leguminous crops — such as the clovers, 

 alfalfa, peas, beans, and peanuts — are 

 usually grown to the best advantage upon 

 soils which are naturally alkaline to a faint 

 degree, or which have been limed. Yet 

 the alsike and white clovers will grow and 

 thrive upon soils which most tests would 

 indicate to be "acid." 



Chemical acids can be added to the soil 

 upon which wheat, oats, or barley is being 

 grown to amounts greater than are usually 

 encountered in any soil, and not infrequently 

 the growth of the crops will be stimulated 

 and not retarded. 



Thus the so-called "acidity" of soils is 

 rather overfeatured in current soil dis- 

 cussion. 



Even if there were any great need for the 

 universal determination of the "acidity" 

 or alkalinity of soils, the proposed litmus test 

 would not furnish the necessary information. 



A soil might become acid from a variety 

 •of reasons. In the first place, all soils 

 contain ip their included atmosphere a con- 

 siderable proportion of carbon dioxide. 

 This, in the presence of the soil moisture, 

 becomes a weak solution of carbonic acid. 



When a sample of soils is moistened and the 

 litmus paper is pressed into it, nearly 90 per 

 cent, of all samples will show a faint acid 

 reaction, as evinced by the red tinge given to 

 the litmus. 



The carbon dioxide is an essential part of 

 the soil atmosphere and very necessary to 

 the growth of the plants. It could not be 

 eliminated from the soil even if that were 

 desirable, since the growing plants and the 

 rainwater are renewing the supply contin- 

 ually. It would require constant attention 

 with a lime sprinkler to eliminate it from the 

 soil or to neutralize it. 



Other acids are being continually formed 

 more or less by the decay of old organic 

 matter in the soil. This is also necessary 

 and inevitable. These acids may accumu- 

 late in swamps or even in some upland soils. 

 The processes of decay which give rise to 

 them are some of the most necessary in the 

 economics of soil sanitation. The acids 

 which are thus given off are of indefinite 

 or unknown composition, and their effects 

 upon soils and upon plant growth are little 

 understood. They seem to be necessary 

 to soil formation and renewal. They would 

 be shown by the htmus test, and their mean- 

 ing could not possibly be foretold from it. 



A very few soil minerals, particularly the 

 sulphides of iron, will decompose so as to give 

 rise to free mineral acids. These are not 

 infrequently harmful where there is any 

 large supply of the original material. They 

 occur, chiefly, in poorly drained bottom 

 lands, and are rarely of any great areal 

 extent. 



Thus "acidity" may arise from a variety 

 of causes, some of which might be harmful, 

 but many of which are beneficial to plant 

 growth and necessary to the proper func- 

 tioning of the soils. 



As to the litmus test for soil acidity under 

 ordinary conditions, little can be said in its 

 favor, and much against it. It is scarcely 

 possible in the majority of cases to determine 

 by the use of litmus paper in contact with the 

 soil whether the soil is acid or not. 



The litmus paper is merely a cellular, 

 fibrous material for absorbing the blue salt 

 of the litmus dye. Litmus itself is red and 

 possesses a weakly acid character. Now the 



soil is also a cellular body capable of a high 

 degree of absorption. As a result, when the 

 dyed paper is put into the moist soil there is 

 a conflict as to which shall secure the red 

 dye stuff, and which the base that makes the 

 dye blue. In many cases, the soil wins. 

 The blue litmus is usually the sodium salt 

 of the red dye and it comes in contact with 

 the soil moisture and is hydrolized. Then 

 the base is absorbed by the soil and the acid 

 by the paper. This simply shows which has 

 the greater attraction for the dye, paper or 

 soil, and does not show whether there is any 

 real soil acidity or not. 



The same reaction may be secured by 

 wrapping the litmus paper in absorbent cot- 

 ton, moistening with distilled water which 

 has been freed of carbonic-acid gas, and 

 aflowing the paper and the cotton to remain 

 in close contact for a few minutes. The 

 paper will turn red by selective absorption, 

 proclaiming the cotton to be "acid," and all 

 of the time you know it is not! 



The danger of a wrong conclusion based 

 upon the litmus "test" is thus very great. 

 Under average conditions neither the gar- 

 dener, nor the farmer, nor the teacher would 

 derive any information about the real con- 

 dition of the Soil. This kind of testing has 

 resulted in the wrong conclusion that the 

 vast majority of soils are acid, a statement 

 very far from the facts. 



There can be no short cut, no handy 

 method for making the determination of the 

 acidity or alkalinity of the soil. 



The real reaction of a soil can be deter- 

 mined in a well-equipped laboratory by a 

 competent analyst who will secure the water 

 extract of the soil, ehminate the carbonic 

 acid gas reaction, and then treat the solution 

 with the sensitive phenol-phthalein which is 

 used for determining not only the quahtative 

 reaction, but also as an indicator of the 

 quantitative acidity of the soil solution. 

 Even when this has been properly done 

 there is need for the interpretation of the 

 results into terms of farm practice. For 

 this the cause of the acidity must be known 

 and its probable effect upon plants of dif- 

 ferent kinds. 



Let us leave the litmus paper in the 

 laboratory, where it belongs. 



