How to Grow Orchids, Part 2 Growth Requirements


The graceful bearing of the Phalaenopsis, whether native species or advanced hybrids is quite pleasing to the eye. The long, slender flower stalk bears the flower high and the arcs away from the leaves appearing fragile yet regal.

The following hybrids are promising for cutflower production:

  1. Large White – Phal Anne Cavaco, P. Grace Palm, P. Dos Pueblos and P. Quisumbing; 1.
  2. White with Red Lip – Phal. Eva Lou, P. Queen Emma and P. Ruby lips; and
  3. White Stripes – Phal. Percy Porter

Growth Requirements

Basically, the growth requirements of any plants are temperature, water, light, aeration and nutrition. These are the environmental factors which a good grower should try to stimulate for each type of orchids.

Temperature – cool-growing orchids prefer night temperature of 10 deg. C to 18.3 deg. C and 15.6 deg. C to 21 deg. C day temperature, like Cymbidiums, Odontoglossums and some Phaphiopedilums.

For the intermediate group like Cattleyas, some Dendrobiums and Oncidiums, night temperature needed is 12.8 deg. C to 15 deg. C and day temperature ranges from 18.3 deg. C to 21 deg. C.

Most orchids grown in the Philippines are warm-growing where night temperature is below 18.3 deg. C and day temperature rising to 21 deg. C to 32 deg. C. These temperatures are ideal for growing Renanthera, Vandas, Phalaenopsis, Aerides, Trichoglottis and Dendrobiums.

Light – sun-loving orchids are Arachnis, Renanthera, Arandas, and terete and semi-terete Vandas.

Partial shade orchids need lower light intensity for healthy growth. Example: Dendrobium, Phalaenopsis, Cattleyas, and strap leaf Vandas.

Orchid plants which receive enough light have short plump stems with yellowish-green leather leaves. Those receiving too much sunlight are yellowish, stunted and even scorched. Those under too much shade become green, soft and succulent with thin spindly stems.

Water – generally, orchids prefer an atmosphere where relative humidity ranges from 50% to 85%. A constantly saturated atmosphere (100% relative humidity) is just as harmful as constantly dry environment. High humidity and relatively low night temperature are conducive to the development of many diseases and pathogens especially soft rot. Growers often water the plants early in the morning so that before nightfall, the leaves are already dry. During sunny days, it may be necessary to increase humidity of the atmosphere by misting or wetting orchid house floor to enhance vaporization.

The need and frequency of watering depend on interacting factors, such as size of containers, potting media, temperature, light intensity and air movement. Orchids in large containers dry out more slowly than those in smaller pots. Plants in baskets, twigs and slabs require more water than those in pots. During drier months, more frequent watering is required. Plants suffering from lack of water become flaccid and stems and pseudobulbs become shriveled.

Aeration – orchids must have free circulating air around them. Orchids are found where there is constant breeze. Stagnant air does not allow drying of potting medium and foliage.

Nutrition – apply fertilizer either through liquid or dry method. By liquid feeding, dissolve water soluble salts and apply resulting dilute solution to plant. The amount and kind of fertilizer required by orchids depend upon growing conditions, potting media, species and stage of development.

Young seedlings are usually given dilute solution of nitrogenous fertilizers or complete fertilizers with higher nitrogen content plus phosphorous and potassium (4-1-1 or 2-1-1). Pig manures, chicken or fish emulsion may be prepared and applied once a week or once a month. As plant gets older, increase phosphorous and potassium level correspondingly.

Generally, under conditions of more frequent rainfall, practice more frequent fertilization as leaching is higher. When plants are dormant or inactive, do not fertilize plants. Plants exposed to higher light intensities also require higher fertilizer or nutrients than those grown under heavier shade.

Potting and Repotting – potting of orchids varies according to genera or species.

For Cattleyas, some growers use clay pots with charcoal as potting medium. Remember not to over pot them as medium remains wet for a long time in big pots. Place the bulb close to rim of pot with the lead towards center. An old Cattleya needs repotting when the plant has overgrown its pot and when potting materials has deteriorated.

For Vandas and Ascocendas, small seedlings are potted with little osmunda fiber and a little charcoal. For older plants, coarse tree fern or charcoal maybe used for potting. Another method is by mounting them in twigs on driftwoods or by hanging them in wooden baskets.

For Dendrobium, pot them in clay pots or mount them on driftwoods. For large-scale production, clay pots with charcoal are ideal.

For Phalaenopsis, mount them in acacia or kakawati wood cuttings, or fern slabs. Or mount them in pots with charcoal and little osmunda fiber.

In potting, the general rule to remember is to allow quick and complete drainage of the potting medium.

Some types of orchids are planted directly in well-drained bed or in soil pots.


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