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GARDEISERS' CHRONICLE 



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I A Lesson on Seed Sowing and Germination | 



I Being One of a Series of Lessons of a Home Study Course on GardeninR. Appearing Regularly in The Gardeners' Chronicle g 



I Under the Direction of ARTHUR SMITH | 



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Proper Time for Sowing 



IT has been my experience in the North-Eastern States, that 

 seed of some species can be successfully sown in the open 

 ground some time during the month of March, especially zvhcn the 

 ground intended for the earliest n'ork had been spaded before 

 Winter set in. 



Frost breaks up the soil far better than can be done by any 

 mechanical operation, and a good tilth can thus be easily obtained 

 with very much less labor. The first step in obtaining successful 

 germination is to make the soil a satisfactory medium for the 

 reception of seeds: and in connection with certain things which 

 only mature well under temperate conditions, such as peas and 

 spinach, and from which it is useless to expect much during 

 hot weather, early sowing is imperative. With pre-winter spaded 

 ground one is in a position to take immediate advantage of the 

 earliest moment in March that the soil is in a fit condition for 

 sowing; this fit condition being that frost is out to the depth of 

 a foot, and that one can walk, or use tools upon the soil without 

 any of it adhering. It is always waste of time to work ground 

 for sowing when it is wet and sticky, although^ we may take 

 certain liberties in this direction with a sandy soil which would 

 ruin a crop were such liberties taken with one of a clavey nature. 



When a soil is friable it falls closely into place around the 

 seed, this assists the seed in absorbing moisture quickly, sprout- 

 ing commences sooner and the whole process of germination is 

 carried on under the best conditions. These conditions are im- 

 possible of attainment when the ground is wet and sticky, or 

 when it is hard and lumpy. 



The Germination of the Seed 



The germination of the seed is not complete until the plrntlet 

 born from the seed is in a position to feed itself. 



While the entire round of plant life is wonderfully interesting, 

 there is no phase more so than seed germination, unless we class 

 as still more wonderful the fact of a plant transferring its life to 

 its seed ; which seed, althou.gh to all appearances dead, contains 

 under norinal circumstances potentialities equal or even superior 

 to its parent plant. The life in the seed can under certain con- 

 ditions be easily destroyed, yet under others it is difficult ' ^ kill. 

 When perfectly dry. seeds are not changed in their vitality by 

 either high (200 F.), or by very low (70 F. below zero) dry 

 temperatures. Practically a seed is a plant in embryo, which 

 embryo is so designed that it will live through conditions which 

 would be fatal to the plant itself. Neither the strongest micro- 

 scope nor the most delicate chemical analysis have any power 

 in determining whether a given seed possesses any vitality or not. 



How TO Test Vitality of Seeds 

 The vitality of seeds can only be determined by a germination 

 test which can be made in the natural way by sowing in soil, or by 

 means of several artificial methods, such as placing the seed be- 

 tween two pieces of moist flannel in a warm room, or by means 

 of a laboratory seed-tester. If one sends a sample of seed to 

 their State Experimental Station for testing, they will sooner or 

 later receive word that the seed germinated so much per cent. 

 This means that a certain percentage of the seeds were viable 

 inasmuch as the germ they contained had sufiicient life to start 

 into growth or sprout. Properly conducted germination tests are 

 carried out under ideal conditions as regards air, moisture and 

 temperature, which will always give a higher percentage of ger- 

 inination than is generally possible when the seed is sown in the 

 ordinary way. Further, in nearly, if not quite, all samples of 

 seeds there are always some in which the embryo, while having 

 sufficient vitality to start into growth by sprouting, is not suffi- 

 ciently strong to complete the act of germination and to produce 

 a plant. For this reason, and for others which will be aiiparent 

 as we proceed, we may calculate that a given sample of seed which 

 will under a properly conducted test show eighty per cent, of 

 germination, will not upon the average give more than forty per 

 cent, of complete germination when sown in the soil under the 

 best conditions ; if the soil conditions are not the best then the 

 percentage will be still lower. 



Obviously the better the entire conditions surrounding the seeds 

 when placed in the ground the greater will be the percentage of 

 plants produced. It is possible for seeds to be sown in the ground 

 without any germination taking place at all. When this happens 

 the blame is generally put upon the seedsman, while the chances 

 are that the seeds which failed to "come up" were perfectlv good 



and that the reasons for their not doing so should be sought for 

 in other directions. 



The embryo in a good seed is in a state which may be likened 

 to deep sleep ; its life is, as it were, arrested, suspended. But 

 unut. the stimulus of certain conditions, it awakes, throws off its 

 coverings, gathers strength from the stored up food within the 

 seed and appears above ground. Moisture, heat and oxygen are 

 the determining causes of germination, which causes are only 

 effective when co-operating together. 



After seeds have been fertilized and ripened, they will, ac- 

 cording to their kind, retain for a longer or a shorter period the 

 power of germinating, but why this vitality is more enduring in 

 one instance and less so in another, is unknown. Neither the bulk 

 of the seed nor the character of its outside coverings appear to 

 decide the longevity of the embryo, which in the case of soine 

 seeds lives for many years while in others it loses its germinat- 

 ing power in a few days or weeks. The differences in time which 

 seeds of various species remain visible are irrespective of the 

 conditions under which seeds are kept; that is to say, it matters 

 not how good these conditions may be, the germ of some seeds 

 will only remain alive for a certain limited period. At the same 

 time, with special precautions and treatment, there is no question 

 that the life of many seeds may be greatly prolonged beyond that 

 which we know at present, although never for centuries as is 

 frequently stated. Cases so reported cannot be taken as evi- 

 dence of the longevity of seeds. 



Longevity of Seeds 



Numerous statements have been periodically made about the 

 great longevity of seeds which are of little value from lack of 

 sufficient positive proof. Perhaps the most notorious are those 

 concerning seeds from the sarcophagi of Egyptian mummies. It 

 is now generally acknowledged that no adequate proof has been 

 produced of this germination, the reputed success being due to 

 the duplicity of vendors palming oft' modern seeds as being taken 

 from the sarcophagi. 



The average life of seeds, as of plants, varies greatly with dif- 

 ferent families, genera and species, but there is no relation be- 

 tween the longevity of plants and the viability of the seeds 

 they bear. As a rule the seeds of trees lose their vitality sooner 

 than most of the annual weeds. For instance, unless seeds of the 

 Elm germinate vv'ithin a few days after they fall from the tree 

 their power of doing so is lost ; while seeds of the annual weed 

 known as Charlock will remain in the ground ten or twenty 

 years, and then germinate when brought near enough to the sur- 

 face to receive a supply of oxygen. In this connection the old 

 saying as regards allowing weeds to seed, that "one year's seeding 

 makes seven years' weeding" is easily understood. 



The Construction of Seeds 



All seeds contain more or less of food materials wherewith the 

 young plant is nourished before it is capable of obtaining its own 

 food from the soil, but it is not perhaps necessary to detail all 

 the various chemical and biological processes which take place 

 during the act of .germination. The chemical changes which take 

 place are similar to those which occur in the di.gestion of food in 

 the animal stomach, and the starch, fat and proteids in the seed 

 are resolved into soluble forms. The diastase and peptonizing 

 ferments are very active in producing the changes in both ger- 

 mination and digestion ; therefore one part of seed germination 

 is in point of fact a digestive process. 



As above mentioned, before germination can commence the 

 co-operative action of moisture, heat and oxygen is necessary. 



The action of moisture in softening the seed, which when placed 

 in the soil is in an absolutely dry condition, must take place first 

 and seeds must be nearly, or quite, saturated with water and the 

 seed-case soft enough for the sprout to break through, before 

 germination can start. 



The unfolding and expansion of the plantlet is largely due to 

 the strong absorptive power for water possessed bvthe proto- 

 plasm within the cells. When water is obtainable' this power 

 causes all parts of the embryo to be constantly full of water, and 

 the elastic cell-walls are distended with water until they arc like 

 minute inflated bladders. The- pressure thus set up aids in un- 

 folding the different parts from their resting place within the 

 seed-case and enables the plantlet to grow out from the seed. Of 

 course growth by cell division soon takes place, but not until 

 after the original cells are filled with water. 



