Read more of Cultivation of Angraecum rutenbergianum Kraenzl.
Culture:
Light:
2000-3000 fc. Light should be filtered or diffused, and plants should not be exposed to direct midday sun. Strong air movement should be provided at all times. Hillerman & Holst (1986) reported that these plants should have fairly strong light, but then stated that the plants have bloomed for them with far less that the recommended 2000-3000 fc.
Temperatures:
Summer days average 74-76F (23-25C), and nights average 56-57F (13-14C), with a diurnal range of 17-20F (10-11C).
Humidity:
5-80% most of the year, dropping to near 65% for a short time in spring.
Water:
Rainfall is very heavy from late spring to early autumn. Amounts then decrease fairly rapidly at the beginning of the 5-month dry season, which lasts from late autumn to early spring. Cultivated plants should be watered heavily while actively growing. Water should be reduced after new growth is completed in autumn.
Fertilizer:
1/4-1/2 recommended strength, applied weekly when plants are actively growing. Many growers use a balanced fertilizer all year. Others, however, prefer to use a high-nitrogen fertilizer from spring to midsummer and then switch to a high-phosphate formula in late summer and autumn.
Rest period:
Winter days average 64-66F (18-19C), and nights average 44-46F (7-8C), with a diurnal range of 19-22F (11-12C). Rainfall in the habitat is low in winter, but additional moisture usually is available from heavy dew and late-night mist. Cultivated plants need less water in winter, but they should not dry out completely or stay dry for long periods. Somewhat regular early-morning mistings between infrequently light waterings should provide sufficient moisture in most growing areas. Fertilizer should be reduced or eliminated until new growth starts and heavier watering is resumed in spring.
Growing media:
Plants may be grown in a shallow, well-drained pot or basket that is filled with a light, fluffy, mix of fir bark or shredded tree fern to which perlite or sphagnum has been added. Adding charcoal to the mix helps hold the medium open and keeps it from becoming sour. Hawkes (1965) reported, "The various bark preparations have not proved to be acceptable for use with Angraecums, or other angraecoid orchids." Therefore, it might be preferable to use fine tree-fern fiber as the base for the potting mix, since it deteriorates more slowly than fir bark. Some growers report growing plants successfully in nothing but perlite or sponge rock. Some growers use a completely non-organic medium after plants reach blooming size so that the roots will not need be disturbed as often. The longer lasting the medium, the less often the plant will need to be repotted. Some orchids from this region may enter a period of no-growth for 2, or even up to 4, years after being disturbed. However, the roots cannot tolerant stale conditions, so plants should be repotted immediately if the medium starts to break down. When repotting is necessary, it is best done just as new roots start to grow. This allows the plant to become reestablished in the shortest possible time. Hillerman and Holst (1986) recommended that if mounted, the slab need not be any larger than 6.0 (16 cm) long by 2.4 in. (6 cm) wide. If mounted, however, plants must be watered at least once daily except in winter when a cooler, drier rest is indicated.
Miscellaneous notes:
In the habitat, plants bloom from late spring to late summer.
References:
This information is quoted from a Charles and Margaret Baker culture sheet, with permission from Troy Meyers
