PKOPAGATION OF PLANTS. 209 



more readily. The soil in all cases about a cutting must 

 be closely pressed against its extremity, or it will never 

 strike root. 



Temperature. — Many cuttings that rarely strike root in 

 the open ground do so freely when moist bottom heat is 

 applied. When the soil is but slightly warmer than the 

 air, the roots grow in proportion to the top, but if the 

 soil is constantly warmer, the disposition to produce roots 

 will be greater than to produce tops. In striking cuttings 

 the object is to produce roots, and then leaves will follow; 

 hence the temperature of the soil should be somewhat 

 higher than that in which the species naturally com- 

 mences growth, in order to secure good roots, without 

 which there can be no vigorous leaf-buds. This stimulus 

 should be applied to soft-wood plants almost imme- 

 diately; others may require some delay until the callus is 

 formed. Deciduous shrubs in a dormant state-should at 

 first be placed in a temperature very little higher than 

 would excite and swell their buds on the parent tree. In- 

 crease the bottom heat gradually, keeping the soil 

 warmer than the atmosphere. From 50° to 60° is about 

 right for the soil at this period, and about 50 for the at- 

 mosphere for hardy and greenhouse plants, increasing 

 the bottom heat to 65° or 70° very gradually, when the 

 roots commence growth. Care should be taken to pre- 

 vent its falling lower until rooted, when it may gradually 

 be lessened until but little above that of the air of the 

 place in which they are growing. 



Moisture. — The cutting, while rooting, must be kept in 

 a suitable state of moisture. In vine cuttings, and others, 

 nearly covered with soil, all that is required is to keep 

 them in such an equable state of moisture that they can 

 have as much as they can appropriate, and no more. A 

 cutting requires more moisture in the soil than a rooted 

 plant. 



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