42 GARDENING INDOORS AND UNDER GLASS 
material to use is broken charcoal, in pieces one-half 
to an inch in diameter. Pieces of broken pots, cin- 
ders or rough pebbles will do. Be sure that the 
drainage hole is not covered; if pieces of pots are 
used, put the concave side down over the hole, as il- 
lustrated facing page 41. The depth of the drainage 
material, or crocking, will be from half an inch to 
three inches, according to the size of the pot. Over 
this rough material put a little screenings, leaf 
mould or sphagnum moss, to prevent the soil’s wash- 
ing down into it. Then fill in with soil and pot in 
the regular way. 
The time for repotting house plants is at the be- 
ginning of their growing season. It varies, of 
course, with the different kinds. The great ma- 
jority, however, start into new growth in the spring 
and should be repotted from the middle of March 
to the middle of May. Plants kept through the 
winter for stock plants are usually started up and re- 
potted early in February to induce the abundant new 
growth that furnishes cuttings. The method 
of repotting will depend on the nature of the plant. 
Soft-wooded plants, like geraniums, are put in in the 
ordinary way and firmed with the fingers. The 
palms do best with the new soil more firmly packed 
about the old ball of roots. Hard-wooded plants 
with very fine roots, like the azaleas, should have 
the soil rammed down firmly about the old ball; for — 
which purpose it is necessary to use a blunt, flat 
