Read more of cultivation of Pterygodium magnum Rchb.f.
Culture:
Light:
2500-4500 fc. Light should be somewhat filtered or diffused, and plants should not be exposed to direct midday sun. Strong air movement should be provided at all times.
Temperatures:
Summer days average 80-81F (27C), and nights average 59-60F (15-16C), with a diurnal range of 21F (12C).
Humidity:
60-65% in summer and early autumn, dropping to 50-55% from late autumn through the following spring. Averages in the habitat are probably somewhat greater than indicated in the preceding climate table, however.
Water:
Rainfall in the habitat is moderate from late spring into early autumn. Amounts then drop fairly rapidly into a dry season that extends from midautumn into early spring. Cultivated plants should watered regularly while actively growing, but their roots should be able to dry fairly rapidly after watering. Water should be reduced after new growth has matured in late autumn.
Fertilizer:
1/4-1/2 recommended strength, applied weekly when plants are actively growing. Many growers prefer to use a balanced fertilizer throughout the year; but others use a high-nitrogen fertilizer from spring to midsummer and then switch to one high in phosphates in late summer and autumn.
Rest period:
Winter days average 67-71F (19-22C), and nights average 36-41F (2-5C), with a diurnal range of 30-31F (17C). Rainfall in the habitat is low for 5-6 months from midautum into early spring, but humidity is high enough so that the large range in temperatures results in heavy dew and late-night and early-morning mist during most of the dry season. As these plants are found in marshy areas, they probably never become very dry at the roots. Water should be greatly reduced for cultivated plants in winter, but they should not be left completely without water for long periods, and the medium should not be allowed to become hard and dry. If humidity is high, infrequent light waterings should provide sufficient moisture in most growing areas. Fertilizer should be eliminated until new growth starts and heavier watering is resumed in spring.
Growing media:
Hawkes (1965) recommended that these plants be grown as for Caladenia. For plants in that genus, he stated, "The cultivation of Caladenias (and many other of the Australian genera of ground orchids) is not a particularly easy matter, but the following recommendations may assist the enthusiast. A perfectly-drained compost is obligatory in all cases; staleness at the roots will rapidly prove fatal to these often fragile plants." He went on to state, "A rather sunny spot suits them best, and fairly good results have been obtained by growing the plants in shallow pans (such as are used for ferns), with about half of the depth filled with broken crock, gravel, or crushed brick. The remainder is filled with a mixture of about equal parts of shredded tree-fern fibre, leaf-mould, crumbled loam, and sharp gritty white sand; some chopped sphagnum moss may also be added to good advantage. The tubers should be only slightly buried, and the compost around them not packed overly firm."
References:
This information is quoted from a Charles and Margaret Baker culture sheet, with permission from Troy Meyers
