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20 



The Weekly Florists' Review* 



Makch 23, IMl. 



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FERTILIZERS 



FOR FLORISTS 



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WHAT THEY ARE AND HOW USED. 



Natural and Artificial. 



A fertilizer is defined as "any sub- 

 stance which, Avhen added to the soil, 

 adds directly or indirectly to the amount 

 of nutritive substances available to the 

 ])Iants growing in that soil." However, 

 to better understand the role that fer- 

 tilizers play in the growing of plants, 

 one should understand what elements are 

 necessary for the development of the 

 jilant itself. 



Among the elements necessary for plant 

 growth are carbon, oxygen, hydrogen, 

 sulphur, potassium, phosphorus, calcium, 

 magnesium, iron, chlorine, sodium and 

 silicon. Although the last three are 

 found in nearly all plants, the plants will 

 grow without them. The question then 

 arises as to where the plant secures these 

 elements. With the exception of carbon, 

 all are taken from the soil. The soil, 

 then, is the source of all the mineral ele- 

 ments which are represented by the ash 

 of the plant. All this mineral food-stuff 

 is taken up in solution through the 

 minute root-hairs of the plant. 



The carbon which is used in building 

 up food substances which are later used 

 in the construction of plant tissues is 

 taken through the breathing pores of the 

 leaves and other green parts of the plant. 

 Carbon is taken up in the form of carbon 

 <lioxide and is decomposed by the energy 

 of sunlight acting on the chlorophyl 

 bodies of the living cell; the carbon and 

 part of the oxygen are combined with 

 other elements to form foods and the re- 

 mainder of the oxygen is given off to the 

 air. As carbon dioxide is always present 

 in the air, there is no need to worry about 

 the source of the supply of this food-stuff. 

 To give the plants a suflScient supply 

 means merely good ventilation. 



The Most Important Elements. 



It is well to study the role of some of 

 tiie more important mineral elements. 



Nitrogen is necessary for cell building 

 or growth. It is specifically directed to 

 increasing the vegetative parts. An ex- 

 cess of nitrogen tends to make the plant 

 grow for too long a period, forming more 

 leaves and shoots and retarding the devel- 

 opment of the flowers and seeds. It also 

 tends to deepen the color of the leaves. 



Phosphorus is necessary for the forma- 

 tion of protoplasm and tends to increase 

 tlie ripening process, particularly seed 

 formation. It thus causes an early ripen- 

 ing of the crop. 



Potassium is necessary for the forma- 

 tion of carbo-hydrates, such as sugar and 

 starch, and plays an important part in 

 the development of the wood and the 

 fleshy parts of the fruit. 



Magnesium is a constituent of chloro- 

 phyl. 



Calcium is present in all plants and 

 serves to. neutralize the acids formed dur- 

 ing growth. 



Iron is necessary for the formation of 

 chlorophyl, and its absence produces 

 chlorosis. 



All these elements are found in the 

 soil in varying quantities, but three of 

 them— nitrogen, phosphorus and potas- 

 sium — arc used in such large quantities 

 that they are likely to become exhausted. 

 These, then, must be added from time to 

 time to secure the best developments. 

 Also, to get the best results, they must 

 be in the proper proportion. The effect 

 of their presence in insufficient quantity 

 or absence of the necessary elements en- 

 tirely is perhaps best expressed by the 

 law of minimum : * * The nutrient present 

 in the soil in. minimum quantity gives a 

 standard for the amount of production 

 as a whole," or, in other words, the lim- 

 ited element determines the size of the 

 crop. 



The availability of an element alsp 

 affects the growth of the plant. The 

 availability is determiifed by the form in 

 which it is found in the soil. 



Necessity for Natural Manures. 



Fertilizers are of two general types, 

 known as natural manures and artificial 

 fertilizers. By natural manures are meant 

 the cleanings from cow barns, horse 

 stables, hen coops, etc., mixed with decay- 

 ing vegetable matter of various kinds. 



Natural manures, when added to the soil, 

 serve two functions: First, they add to 

 the supply of the elements necessary for 

 growth; second, they improve the phys- 

 ical properties of the soil. Those soils 

 that are clayey and compact are made 

 more open and porous by the separation 

 of the particles so that air and water can 

 enter more freely, thus acting directly on 

 the insoluble constituents. The roots of 

 the plant can also penetrate more readily. 

 Those soils that are light are also bene- 

 fited, by the filling of the spaces between 

 the particles, thus making it more com- 

 pact. Artificial or commercial fertilizers, 

 on the other hand, merely add to the fer- 

 tility without making any great change 

 in the physical properties of the soil. 

 This is not always true, as a few are 

 sometimes injurious if used by them- 

 selves. 



It must also be kept in mind that 

 bacteria do much to increase the fertility 

 of the soil, by making many of the in- 

 soluble compounds soluble. To give these 

 helpful forms the best chances for devel- 

 opment, the soil must contain decaying 

 organic matter. It is well, then, to keep 

 in mind that a small quantity, at least, 

 of natural manure should be added to our 

 greenhouse soils. 



In the past the tendency has been to 

 use nothing but natural manures, but 

 their scarcity in the present day has made 

 it necessary to add commercial fertilizers 

 to the florist's list. 



Of the natural manures the two that 

 are in most common use are barnyard 

 and stable manures. These differ some- 

 what in character. Barnyard manure is 

 a cold manure and ferments rather slowly, 

 so that there is less danger in its use 

 when it is not thoroughly decayed. Stable 

 [Concluded on page 62.] 



Hiram E. Wilson. 



