PROPAGATION OF CACTI FROM SEEDS. 



9 



through a sieve of about J-iiich mesh, which removes any large 

 particles and all superfluous root fibers, making a loose soil which 

 drains very readily. It is not necessary that the soil be very rich in 

 humus, and manured soils should always be avoided because of their 

 undue tendency to hold moisture. They are also a medium for 

 producing germs of decay. An open, drahiable soil is the chief 

 requisite for cultivating cacti. 



For germinating the seeds an ordinary 4-inch pot is very con- 

 venient. New pots are preferable, but old pots may be used with 

 safety if thoroughly sterilized. Porous pots are soon covered with 

 green algae when left in a moist place for any considerable time. This 

 growth will spread over the surface of the soil in a close blanket which 

 precludes the free access of air and seriously retards the drainage of 

 superfluous water. These algae will in time grow over the little 

 seedlings that have survived other adverse conditions and will 

 smother them to death. To combat the algae the pots should be 

 thoroughly sterilized just previous to being used, and to accomplish 

 this object two efficient methods have been found. One method is to 

 bake or burn the pots, so that all life on them or in their pores may be 

 destroyed. The other method is to soak the pots for a time in a weak 

 solution of copper sulphate and then thoroughly wash them in the 

 same solution. If a very strong solution of the copper sulphate is 

 used, some of it will be left in the pores of the clay, and later, when the 

 seedlings are being watered, enough may pass through the soil to 

 injure the tender young plants. 



Reasonable care should be exercised in preparing the pot for plant- 

 ing. As a rule the drain hole in the bottom of the pot is too small and 

 is easily clogged. This hole should be enlarged, as thorough drainage 

 must be maintained in growing cacti. The pot should be filled to 

 one-fourth its depth with small bits of broken pots, and on these the 

 prepared soil should be placed and pressed or shaken together firmly 

 but not packed hard. The soil surface is then leveled by the use 

 of a round, flat-faced tamper of a diameter to just fill the pot. 

 The soil should not be packed but should be lightly tamped, 

 with only sufficient effort to produce a smooth, level surface. This 

 surface should be about half an inch from the top of the pot. Over 

 it the seeds are evenly distributed and then covered with a very thin 

 layer of soil, upon which is spread a layer of fine gravel to a depth of 

 about one-fourth of an inch. This layer of gravel is important in 

 many ways. As the pots are later watered with a fine spray, it 

 prevents the surface of the soil from washing and consequently keeps 

 the seeds from being disarranged. It also promotes the free passage 

 of moist air through the spaces between the bits of gravel, which, 

 together with the shading by the gravel, prevents the surface of the 

 56603°— Bull. 262—12 2 



