8 



Cereus should be grown in orchidlike conditions of temperature and 

 humidity, but in very loose, moderately rich soil. For this purpose 

 a mixture of loam, sand, and an abundance of thoroughly decomposed 

 leaf mold makes an excellent soil. By far the greater number of 

 species of cacti are terrestrial in their habits and are indigenous to 

 warm, semiarid regions. The annual rainfall in these regions is 

 very slight and continues for only a, brief period. It is difficult to 

 reproduce such conditions in our northern climate, and it is found 

 that cacti can best be grown here by minimizing the action of our 

 abundant rains by having the plants placed in a thoroughly well- 

 drained situation. It is equally difficult to reproduce the conditions 

 in our conservatories, where they are heated artificially, because of 

 the drying effect of the heat. This condition may be largely coun- 

 teracted by a judicious watering of the soil about the plants. For 

 this group of plants it is not necessary that the soil be rich, but it 

 is essential that it be very open and thoroughly drained. 



In repotting older plants it is best to disturb the roots as little as 

 possible. Enlarge the drain opening in the bottom of the pot and 

 place over it bits of broken pots or other coarse material to a depth 

 of not less than 1 inch, to insure perfect, uniform drainage. Over the 

 coarse material put a layer of soil. Remove the plant to be repotted 

 by inverting the pot and gently tapping its rim on the edge of a bench 

 or some such solid structure. The whole body of dirt will come out in 

 a lump. Remove any bits of broken pots that may be attached to 

 the bottom, but leave the soil in place about the roots. The surface 

 soil should be removed if it shows any evidence of containing algae or 

 fungous growths. Place this ball of dirt and roots in the next pot 

 and pack fresh soil about it, leaving sufficient space at the top to 

 receive water. In conservatories pots are apt to become coated with 

 green algae, and old pots especially so, because the spores of the 

 algae are likely to remain in the pores of a pot from its previous 

 use. pid pots should be thoroughly sterilized, as heretofore ex- 

 plained for the germination pots. After the plant is potted, the 

 surface of the soil should be covered with fine gravel to a depth of 

 at least half an inch. 



The soil about the plants should never be allowed to become 

 absolutely dry for any great length of time or the roots will be 

 seriously injured; on the other hand, it must not be kept saturated, 

 but should be kept slightly moist at all times. Any superfluous water 

 standing about the base of the plant or in the soil about its roots 

 is a serious menace, since it acts as a medium through which germs 

 of rot enter the plant and soon destroy it. Cactus plants contain 

 so much liquid that decay works very rapidly through them. When 

 decay once starts it is difficult to save the plant, hence the urgent 

 necessity for having thorough drainage below the plant and a 

 thoroughly drainable soil. Failures' in the growing of c^cti are 

 undoubtedly due more to the neglect of this precaution than to 

 other causes combined. 



Cacti do not need to be pruned beyond the remove ^>r ^ por- 

 tions and to keep the plants in shape within the space t*. .Lied to 

 them. Pruning may be done at any time, but preferably when the 

 atmosphere is dry, so that the cut surface may dry and heal quickly. 



