Decline of Growth and the Best Period. Ill 



not germinate as soon as ripe, they i^nitate nature by 

 the process known as 



169. Stratification of Seeds. This consists in mixing 

 the freshly-gathered seeds with sand, taking care that the 

 sand is kept moist until the time for sowing arrives. 

 Large quantities of seeds may be stratified in boxes, by 

 placing the moist sand and seeds in alternate layers, or 

 the layers may be built up in a pile on the ground. 

 The sand should be coarse enough to admit some passage 

 of air between the particles and to give perfect drain- 

 age. The layers should not much exceed an inch in 

 thickness, except for the larger seeds, and the number 

 of layers should not be so large as to prevent proper 

 aeration of the mass. Small quantities of seeds may be 

 mixed with sand or porous loam in flower-pots. Moist- 

 ure may be maintained in the boxes or pots by burying 

 them a foot or more deep in the soil in a well-drained 

 place, or by storing them in a moist cellar. Care is neces- 

 sary to keep mice and other vermin from stratified 

 seeds. It is well to cover pots in which valuable seeds 

 are stratified, with a sheet of tin or zinc; metal labels 

 are best for distinguishing different sorts of seed. The 

 seeds should remain stratified until sowing time, when 

 they may be sifted out of the sand or sown with it, as 

 is more convenient. Seeds that do not germinate well 

 until the second spring after maturity (162) are com- 

 monly left in stratification until that time. 



