564 



THE GARDENER'S ASSISTANT. 



rest in a cooler temperature, viz, Thunias, 

 Calanthe vestita and its varieties, C. Veitchii, 

 C. Regnieri, and all that section, require a 

 strong heat when growing. These all start in 

 February or soon after, and when the new 

 growths are seen to be an inch or so in length, 

 they should be repotted, placing the largest 

 bulbs singly in 5 -inch pots, and the smaller 

 ones several together. They should then be 

 placed on a stage or shelf near the roof-glass, 

 and kept tolerably dry until the roots are seen 

 to be taking hold of the soil, when they may 

 be watered liberally and regularly until the 

 growths are fully made up. During active 

 growth a little very weak liquid cow-manure 

 may be given them. When the leaves begin to 

 turn yellow, water should be given sparingly, 

 and on the flower-scapes appearing only sufficient ! 

 water should be given to keep them going. 

 After flowering, the plants should be stored [ 

 on a dry shelf in a temperature not less than 

 55° Fahr., and be kept entirely without water 

 until repotting time. Cypripediums may with 

 safety be repotted whenever they require it, 

 after they have flowered being perhaps the . 

 most convenient time. Disa grandiflora, D. I 

 racemosa, 1). tripetaloides, and the hybrids from J 

 these, should be repotted in October and kept 

 in a cool house. They require water all the 

 year round, but especially heavy waterings 

 from February until their flowers are over. 



Hardy and cold-frame Orchids are chiefly the 

 North American Cypripedium spedabile, C. acaule, 

 C. pubescens, C. parviflorum, Ac. and the best of 

 the European species of Orchis, Ophrys, & c. 

 Some succeed with them, but many fail because 

 they do not consider the nature of the plants. 

 They grow mostly in moist woodland or boggy 

 situations in decayed moss or other decom- 

 posed vegetable material, and although they 

 experience cold in winter, they are protected 

 by fallen leaves and snow. These facts should 

 indicate the treatment most suitable for them 

 under cultivation. They do best on the shady 

 side of a rootery or rockery, in moist situations, 

 in the material recommended for terrestrial 

 Orchids, to which about one-third its bulk of 

 well-decayed leaf-soil has been added. At the 

 approach of winter about 4 inches of sphag- 

 num moss, or of dry leaves, should be lightly 

 placed over the crowns, and this should not be 

 removed in spring, but allowed to settle; it 

 should be renewed every autumn. In spring 

 and summer they require plenty of water; but 

 after flowering, as a rule, no water need be 

 given, the rains supplying sufficient. Those 



who prefer to grow them in an unheated pit 

 or frame will find them do best in well-drained 

 pots or pans, and kept copiously watered. On 

 the approach of hard frosts in winter some dry 

 leaves or other material should be placed over 

 the crowns, and the frame closed, not to be 

 opened until spring. 



Satyriums may be grown successfully in an 

 unheated frame in full sun. During winter 

 they should be covered with 6 inches or so 

 of dry leaves, to be removed in March, when 

 the tubers should be repotted and watered. 

 They flower in summer, and after flowering 

 require no water. Many of the South African 

 Habenarias, deciduous Disas, &c, which have 

 been found so difficult to manage in green- 

 houses, would probably do well if treated in 

 this way. 



Ventilation. — Whatever the temperature of 

 the air, it should be pure, and to ensure this, free 

 ventilation must be resorted to. The ventilators 

 should be just above the ground-line for the 

 lower ventilators by which air is admitted, and 

 at the highest point in the roof for the egress 

 of the vitiated air. At the same time care 

 must be taken that the openings of the venti- 

 lators are carefully balanced so as not to cause 

 currents of air likely to be injurious. For this 

 reason it is better to open all the ventilators an 

 inch or so than to open two or three of them 

 wide and allow the rest to remain closed. 

 Bottom air may be conveyed to each house by 

 laying large drain-pipes from the outside of the 

 block. The pipes should be open to receive air 

 outside the house, and openings in them should 

 be made inside the house to allow the ingress 

 of fresh air. 



The ventilators are important as a means of 

 regulating the temperature of the house. Care, 

 however, should be taken not to put on too 

 much air, especially by opening the top ven- 

 tilators. A draughty house, though cool, is far 

 more injurious than a close house. Except dur- 

 ing very severe weather, when the fires have to 

 be worked hard, air should be left on the bottom 

 ventilators all night and all the year round, 

 plants thus treated soon showing by their ap- 

 pearance that it is good for them. It is a wise 

 plan to cover the insides of the traps of the 

 bottom ventilators with fine wire-netting, to 

 keep out cats, rats, &c. 



Moisture is a very essential factor in the health 

 of Orchids, and the distribution of water on and 

 under the stages and on the floors assists towards 

 keeping the correct temperature and a humid 

 atmosphere. In spring, summer, and early 



