no 



GARDENERS' CHRONICLE 



seed has begun to sprout, if the oxygen supply is cut off, the 

 plantlet makes no further progress. A soil in the best condition 

 for germinating seeds and the continual growth of crops to a 

 maximum degree, must permit of the ready entrance of fresh 

 air ; in other words it must be thoroughly aerated and constantly 

 ventilated. . 



But it sometimes happens that atter seeds are sown, heavy 

 rains cause the soil to run together and to be beaten down 

 more or less solid, and soon after hot sun may cause the forma- 

 tion of a hard crust upon the surface, a condition which not only 

 cuts off the air suppiv, but also prevents the shoots fror, the 

 seeds from readily pushing through. This condition occurs more 

 easily on some soils than others and is most troublesome m those 

 containing much clay and little humus, and which have been only 

 a short time under proper garden treatment. When this condi- 

 tion has been brought about it is advisable to carefully bre^k the 

 surface of the soil over the seed with a tine rake, this should be 

 done as soon as the surface is dry enough to prevent sticking 

 and before it bakes hard. , , , 



The necessity for oxygen explains why seeds planted too 

 deeply fail to germinate, and why weed seeds remain so long in 

 the ground and continue to come up every time the soil is turned 

 over This is one reason why seeds must not be planted too 

 deeply, another reason being that too great a depth of soil foi 

 the plantlet to push through may cause the food in the seed to be 

 exhausted before the plantlet reaches the surface, even if the 

 seed has been able to obtain sufficient oxygen. Generally speak- 

 ing large seeds may be planted deeper than small ones and one 

 of the main objects in covering seeds with soil is to place them 

 in contact with moisture and as the plantlet must force Us \,ay 

 through the soil which covers the seed, the less the depth of this 

 soil— all other things being equal— less energy and shorter time 

 are required for the plantlet to reach the surface, imall seeds, 

 like lettuce, celery and carrot, naturally contain very little food 

 for the pla'ntlcts, therefore these plantlets are weak and cannot 

 fully oerminaie if covered too deeply. With these it is a good plan 

 to merely press them into the soil with a board, and after to 

 just merely cover them with fine sand. It is the usual practice 

 to shade small seeds, that must be sown almost on the surface, 

 in a frame or greenhouse, with newspaper, muslin, or lath 

 screens care being taken to prevent the plantlets becoming 

 drawn 'and weak by removing the shading as soon a. germina- 

 tion is complete. When seeds are sawn in a pot or flat, covering 

 them with a sheet of glass will retain moisture while at the same 

 time allowing the plantlets the necessary light as soon as germina- 

 tion has taken place. Very small seeds sown in this way, such 

 as begonia, petunia and tobacco, should not be covered with 

 soil, but merely pressed down into fine, moist (not wet) sandy 

 loam and covered with glass. 



Dkpth .^t Which Seed is Sown 

 While the depth at which seed is sown is, as a rule, governed 

 by its size, this rule, like all others, is subject to exceptions, 

 which exceptions are connected with the actual method of 

 germination practiced by different seeds. For instance take peas 

 and beans ; although the latter are much larger yet they will not 

 germinate fully at so great a depth as will peas. If we take a 

 pea and a bean and soak them in water so that the seed case can 

 DC easily removed, and then if we carefully dissect them we shall 

 find that the seeds will readily divide into halves, botanically 

 known as cotyledons, between each half we shall be able to ob- 

 serve the embryo compactly folded up. These cotyledons con- 

 tain the material for feeding the plantlet until it is capable of ob- 

 taining food from the soil. In the case of the pea the cotyledons 

 remain in the soil during germination, and the shoot, or plumule, 

 commences growing upwards and the root, or radicle grows 

 downwards. But in the case of the bean — and the same thing 

 occurs with the pumpkin family as well as others — the cotyledons 

 must reach the surface of the ground before the shoot com- 

 mences to grow ; the growth between the root and the cotyledons 

 being known as the hypocolyl. It obviously follows that con- 

 siderably more energy is required to push the cotyledons of the 

 bean through the soil than is necessary with the sharp shoot of 

 the pea. While therefore the latter will germinate through a 

 covering of soil as great as six inches, the bean does not readily 

 do so if planted to a greater depth than two or three inches ac- 

 cording as to whether the soil is sandy or clayey. If beans are 

 covered with too much soil the plantlet is unable to push its 

 cotyledons to the surface and in which case it perishes. Some- 

 times in the persistent struggle which the plantlet makes to ap- 

 pear above ground the cotyledons get torn off, which also results 

 in death. When cotyledons of plants appear above the soil in 

 germination they are known as seed-leaves. While in most cases 

 beans will, if the soil is more or less light, germinate through 

 three inches, it is never wise to cover them to a greater depth than 

 two inches in one of a clayey nature. 



Referring again to peas, while these will push through a con- 

 siderable depth of soil yet, in connection with March and early 



April sowing, it is better to only covci them to a depth of two 

 inches so that the shoot can get above the surface as soon as 

 possible, as bad weather after sowing appears to have less ad- 

 verse effect after germination than it does before. At the same 

 time one of the advantages of early sowing is to enable a good 

 depth of roots to be formed before hot weather which depdi 

 is secured by deep sowing. We can, however, secure the bene- 

 fits of both quick completion of germination and deep rooting 

 by making a trench for the reception of peas four or five inches 

 deep, sowing the seeds along the bottom of the trench and cover- 

 ing them with only two inches of soil. After which, as the peas 

 grow, the trench should be gradually filled in. Later on in the 

 season as the warmer soil enables germination to take place more 

 quickly, we may cover peas more quickly to start with. 



L'sE OF Fertilizers in Seed Sowing 



Germination is liable to be prevented if seed is sown in contact 

 with compound chemical fertilizers, acid phosphate, or any other 

 inorganic fertilizer containing acid. The chief injury from this 

 cause is inflicted upon the young sprouts just as they leave the 

 seed case; injury to the seed itself before germination has started 

 is not so likely unless the amount of fertilizer it comes into con- 

 tact with is large. Organic fertilizers, such as sheep manure, 

 pure ground bone, do no harm either to the seed or to the sprout- 

 ing plantlet. Dissolved bones are liable to inflict injury because 

 they are dissolved by acid. 



How TO Observe the Germination of Seed 



It is interesting and instructive in many ways to watch the 

 germination of seeds. This may be done by means of a glass 

 case about a foot long and deep, and six inches wide ; provision 

 should be made at the bottom for drainage. Put a layer of one 

 inch of sandy loam at the bottom and then place some large seeds 

 of different kinds around close to the glass so that no soil comes 

 between the seed and the glass. Then add another layer of soil 

 and plant some more seeds, and so on until the case is full within 

 an inch of the top. As the case gets full smaller kinds of seeds 

 can be used. Large seeds like beans, pumpkins, &c., should be 

 placed in varying positions, such as upright and flat. By this 

 means the process of germination and the behavior of the plantlet 

 can be watched through the glass, under the varying conditions 

 of depth of soil, &c. Sometimes the root will emerge from the 

 top of the seed, in which case the extraordinary phenomenon of 

 the root turning a complete semi-circle so as to grow downwards 

 will be observed. This characteristic is one of the facts u^ed to 

 show that plants have brain-power. The case should be placed 

 in a warm room, or greenhouse, and the soil kept moist. 



Princip.^l Points to Remember 



From what lias been stated, and the subject has by no means 

 been exhausted, we may adduce the following points, amongst 

 others : 



A seed is a living organism and must be dealt with as such 

 from the time it is ripe on its mother plant until it has germinated 

 after sowing. 



Ground intended for the reception of seeds should be thorough- 

 ly prepared and should be in a friable, crumbly condition at th 

 time of sowing. For early spring work such conditions are best 

 secured by turning up the soil in late autumn. 



Preparing the soil for the actual reception of seeds should not 

 be done when it is wet and sticky ; special care in this connection 

 is necessary with clay soils. 



Seed should not be planted too deeply, otherwise it may not 

 germinate at all or the plantlet may be unable to reach the surface. 



While seeds of plants native of temperate zones, like peas, may 

 be sown in the Spring when the temperature of the soil is just 

 above freezing point, provided all other conditions are right, one 

 has to wait until the soil is warm — as well as consider possi- 

 bilities of future frost — before sowing those of plants from warm 

 climates. 



Seeds of the highest quality arc always the cheapest, whatever 

 their cost. Bearing in mind also in this connection that plant 

 diseases can be transmitted by seeds. 



THE MONTH'S WORK IN THE GREENHOUSE 



{C'liitiiiitcd from /"(igc 102) 

 sary in order to make perfect plants. Good foliage is 

 neces.sary in order to give the flowers the proper setting. 

 These plants are always benefitted by being placed in a 

 temperature of 50 degrees as soon as the first flowers 

 begin to open. They need water in abundance, and if 

 they are well spaced and the foliage kept dry it is hardly 

 possible to give them too much at this time. 



