The store-pots should be returned to the seedling case, or placed on a shelf near the glass in a warm, moist house, where the seedlings should increase in size until they are ready to remove to fresh store-pots, when they may be given more room; or if large enough, they may be placed singly in thimble pots, or three or four seedlings may be placed round the rims of thumb pots.
Seedling Odontoglossums, when large enough to occupy thimble pots, are found to thrive well when the pots are fixed in pans or shallow seed-boxes in Sphagnum-moss, and placed on a shelf near the glass in the Odontoglossum house, where, like other seedling Orchids, they should be lightly sprayed several times each day in fine, warm weather, and as often as may be deemed necessary in colder and dull weather.
From the time the little plants are established in small pots until their flowering stage, it is only a matter of ordinary culture, although, as a rule, the small seedlings are safer with four or five degrees more heat than is afforded the established plants. In the matter of growth from the seedling stage to the flowering plant, there is but little need of a resting season, even with species such as are deciduous when mature, although a diminished supply of water may be given for a short time to any which, having completed a growth, show no sign of developing a fresh one. In most cases, a thorough drying, even if it does not destroy a seedling, causes the flowering season to be delayed by a year, or even longer.
The careful shading of the seedling house is a very important matter. Very young plants do best in a subdued light, and until they are quite strong plants they should not be exposed to direct sunlight. A hot summer often kills even the plants which have been brought satisfactorily through a long winter. It is, therefore, advisable to have on the seedling house, in addition to the lath roller blind, running on supports carrying it well above the glass of the roof, either a second lath roller blind running an inch or so above the glass and beneath the upper one, or a permanent thin cotton shading, which may be tacked on in spring and left until autumn; or, preferably, so fitted that it can be rolled up when it is not required.
SELECTION OF SUBJECTS FOR HYBRIDISING
The best varieties procurable should always be selected for hybridising, it having been proved that crosses originally made with indifferent varieties are much finer when raised again from more carefully selected varieties.
There seems to be no certain limit to the possibility of crossing; even the most dissimilar genera may be crossed with some probability of getting a successful result.
POTTING MATERIAL FOR HYBRID ORCHIDS
From the time the little plants are well established in single pots, the same potting material used for all of their kind may be employed, the plants in the earlier stage having the potting material in a finer condition than that provided for the larger plants as they approach the flowering stage.
As with other important operations, in Orchid potting and in the material used the practice varies considerably, even in the best collections, and this points to the fact that if the accommodation is good, the houses properly heated, and other details of culture carefully carried out, the exact composition of the potting material is of minor importance. For Cattleya and Lælia hybrids and a large number of epiphytes grown with them the compost is made by tearing up the materials with the hand, or in some other way which will not break the fibres very much. Osmunda fibre forms one-half to two-thirds of the compost, the other third being made up of good Sphagnum-moss and Oak leaves or other decayed, dryish leaves. We do not recommend leaf-soil or leaf-mould, which was formerly strongly advocated, especially by Continental growers, who used it with disastrous results. The most that is done now is to mix a proportion of it with other potting material for Lycastes, Calanthes, Phaius, and similar strong-growing terrestrial Orchids.