228 DEPTH AT WHICH TO SOW SEEDS. 



with force enough to prevent its passing off too quickly through 

 the wide interstices of sand and peat. 



If, during the delicate action of germination, the changes 

 that the seed undergoes take place without interruption, the 

 young plant makes its appearance in a healthy state; but, 

 if by irregular variations of heat, light, and moisture, the 

 progress of germination is sometimes accelerated and some- 

 times stopped, the unstable forces upon which vitality depends 

 may become so much deranged as to be no longer able to act, 

 and the seed will die. It is for the purpose of securing unifor- 

 mity in these respects, that we employ, in delicate cases, 

 the steady heat of a gentle hot-bed, shaded; and, in other 

 cases, the assistance of a coating of earth scattered over the 

 seed. 



Under what depth of earth seed should be buried must 

 always be judged of by the experience of the gardener : but it 

 should be obvious that minute seeds, whose powers of growth 

 must be feeble in proportion to their size, will bear only a very 

 slight covering ; while others, of a larger size and more vigour, 

 will be capable, when their vital powers are once put in action, 

 of upheaving considerable weights of soil. As, however, the 

 extent of this power is usually uncertain, the judicious garde- 

 ner will take care to employ, for a covering, no more earth 

 than is really necessary to preserve around his seeds the 

 requisite degree of darkness and moisture. An erroneous 

 opinion is not uncommonly entertained, that seeds must be 

 "well" buried in order that the young plants, when produced, 

 may have " sufficient hold of the ground." But a seed, when 

 it begins to grow, plunges its roots downwards and throws its 

 stem upwards from a common point, which is tlie seed itself; 

 and, consequently, all the space that intervenes between the 

 surface of the soil and the seed is occupied by the base of the 

 stem, and not by roots. This is well illustrated by the germi- 

 nation of such seeds as those of the Araucaria, which always 

 grow best when merely laid on the surface of the soil with a 

 little earth raiised round their edges. 



The finest Oaks spring from acorns dropped in the forest 

 and covered by a few leaves. The Sycamore, the Ash, thp 



