This section is from the book "Commercial Gardening Vol2", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Comparatively few Orchids like direct bright sunshine, though they like good light. The houses should therefore be in a light open position, but well provided with blinds. Established Cattleyas and Laelias succeed under lighter and brighter conditions than do Odontoglossums, but all Orchids need practically all the good light we can afford them during the winter months, in this country. Top ventilators should be provided, but their use for the admission of fresh air or the reduction of temperature must be severely limited. Bottom ventilators on both sides of the houses are a necessity, and there should be a number of them placed so that the outside air passing through them into the houses will be warmed by the hot-water pipes ere it reaches the plants. Top ventilation coupled with bottom ventilation tends to dry out the atmosphere quickly, and a dry atmosphere is not conducive to the best results. Moisture - holding material, such as clean cinders or gravel, on the stages is essential, and if the plants can be raised above this material on a light open trellis staging so much the better.
Fig. 287. - Odontoglossum crispum (white form).
Practically all Orchids need far less moisture, both at the roots and in the atmosphere, during the period that follows immediately upon the completion of their growth for the season. In the case of Cattleyas, and especially Dendrobiums, the season of "rest" is very marked, and an abundance of water while the plants are comparatively inactive will quite spoil flower production and at the same time enfeeble the plants. Cypri-pediums, Phalaenopsis, Oncidiums, Odontoglossums, and Coelogynes do not require so decided a season of rest, and with a few rare exceptions, that do not concern us here, they must not be "dried off", to use a technical phrase that is well understood among Orchid cultivators.
A word or two as to the potting material. There was a time when peat was the basis of all potting composts for Orchids, but it is wellnigh impossible now to obtain the best fibrous peat, such as formerly delighted the hearts of growers. Good substitutes for peat are found in Polypodium fibre, or the increasingly popular Osmunda fibre. These fibres are imported in large quantities, and, in combination with the large-headed sphagnum, form the great standby among orchidists. A small addition of oak or beech leaves, gathered clean at the time of fall, and stored under cover for a year, is made by many growers, and where the watering is done with great care this addition encourages root action and increases the vigour of the growths. An excess of leaves, however, tends to the production of large but not substantial flowers; therefore this must be guarded against, because anything that detracts from the lasting properties of the blooms reduces their value in the market.
Pure air and good light are of the utmost importance in Orchid culture, and we have only to observe how splendidly Orchids grow in districts far removed from towns and factory districts, and then inspect collections in the immediate neighbourhood of a great town or city, to discover how environment influences the plants. Further, the work of sponging the plants and cleaning the roof glass in districts where the atmosphere is laden with impurities is very considerable, and would materially increase the cost of production without any compensating advantage. Orchid flowers for the great cut-flower markets are produced chiefly in such pleasant places as Haywards Heath and Balcombe, Broxbourne, St. Albans, Cheltenham, the outlying suburbs of Liverpool and Manchester, etc.
The prices obtained for Orchid blooms vary greatly. For the "weedy" flowers already indicated the returns are low. Odonto-glossums range from 2s. to 6s. per dozen, and Cattleyas from 6s. to 18s. or even 24s. per dozen. Dendrobiums may realize from 1s. to 3s. per dozen, and Coelogyne cristata sell at a somewhat similar rate. Large sprays of golden Oncidiums will range from 1s. to 5s. each, according to their size, quality, and colouring, while a fine spike of a Phalaenopsis may bring anything from 3s. to 20s. The Cypripediums are most in evidence during the dull months of the year, and as they are particularly long-lived when cut they are extremely popular for personal wear or general decorations. The common Cypripedium insigne is sometimes offered in the City of London, by the street flower girls, at one penny each, consequently the return to the grower must in such cases have been a very small one indeed. However, when choice flowers are sold at such a low rate it usually happens that the market has been overloaded with them for once in a way; well-grown flowers should realize from 1s. to 3s. or 4s. per dozen, according to their size and variety. Referring again to Cypripedium insigne, it must be remembered that this Orchid is an easy one to manage, and in an ordinary season it does not require artificial heat for three or four of the warmer months of the year. A plant in an 8-in. pot should produce a dozen flowers, and a fair-sized house will hold a very large number of such plants; and so it is not difficult to estimate fairly well the number of blooms a given area devoted to their culture will produce.
Fig. 288. - Dendrobium nobile.
Fig. 289. - Dendrobium Wardianum.
Orchid flowers are sent to market in shallow boxes, and wrapped lightly in an abundance of tissue paper. Cotton wool is sometimes used to line the box, but every care must be taken to keep this from direct contact with the flowers, because if it adheres to the blooms - as it very often will, owing to the slight stickiness of the flower stems - it is objectionable and will militate against their sale, or at any rate reduce their value.
For cut flowers the Orchids most grown are as follows: Cattleya aurea, C. Bowringiana, C. labiata, G. Schroderce, C. Trianoe, G. Mossioe, G Mendelli, C. Harrisonioe, and C. War-scewiczi. Dendrobium aureum, D. Ainsworthi, B. nobile (fig. 288), D. crassinode, D. Falconeri, D. splendidissimum, D. Phalce-nopsis Schroderianum, and D. Wardianum (fig. 289). Coelogyne cristata and its lovely white form are "cool" Orchids of great value for cut flowers, but, alas! they do not travel well, and their blooms are so easily damaged if at all roughly handled, every slight bruise soon turning to a brown or blackish mark of disfigure-ment.
Among; Odontoglossums the favourites are 0. crispum, 0. cirrhosum, 0. Harryanum, 0. grande, 0. Pescatorei, 0. trium-phans, 0. Rossi majus, and 0. Wilckeanum, with such hybrids as 0. ardentissimum, 0. Lam-beauianum, 0. Adrianoe, 0. amabile, and 0. excellens. Of the Phalaenopsis the most useful are P. Rimestadtiana, P. Schilleriana, P. amabilis (or P. grandiflora, fig. 290), and P. Stuartiana. The most notable of Oncidiums for the purpose under consideration are 0. flexuosum, 0. varicosum Rogersii, 0. bracteatum, 0. crispum, 0. concolor, 0. sarcodes, 0. Marshallianum, 0. macranthum, and 0. incurvum. Cymbidiums must not be forgotten, as their flowers are very lasting when cut; G. Lowianum is the most popular and its green and brown flowers are known to almost everyone. C. eburneum and the newer C. insigne (Sanderoe) are also valuable.
The list may fittingly conclude with a selection of Cypripediums or Lady's Slipper Orchids. The difficulty is to know where to stop, because so many species, varieties, and hybrids are now so largely grown. However, there can be little mistake about C insigne, C. Leeanum, C. Charles-worthii, C. Fairrieanum, C. Spicerianum, C. villosum, C. barbatum, C. Lawrenceanum, C. niveum, and C. callosum. [C. H. C]
Fig. 290. - Phaloenopsis amabilis.