Orchid Web Designs

Oncidium (on-SID-ee-um)

This is an extraodinarily large and diverse New World genus with an equally diverse number of habitats. Oncidiums may origniate anywhere from sea level in the tropics to the high elevations of the Andes. This obviously makes cultural generalization diﬃcult. Some genera included are Aspasia, Brassia, warm-growing miltonias, and many of their hybrids.

Temperature

For this group, they are generally considered intermediate to warm, 55oF to 60oF at night, and 80oF to 85oF during the day. Temperatures up to 95o-100oF are tolerated if humidity and air movement are increased as the temperatures rise, a good general rule.

Light

Oncidium light needs can vary from bright to nearly full direct sun depending on the species. Most will thrive with one to several hours of sun a day. Generally, thicker-leaved plants, such as “mule-ear” and “equitant” oncidiums, can stand more light. In a greenhouse, 20-60% shade is required, or about 2000-6000 footcandles, depending on the plants. In the home, east, south, or west windows are good. Many types of oncidiums will grow under artiﬁcial light. Four ﬂuorescent bulbs and placed 6-12 inches over the plant are necessary for proper growth. Metal-halide and sodium-vapor bulbs also provide suﬃcient light without nedding to be so close to the plants.

Humidity

It should be between 30-60%. Many oncidiums require less humidity than other orchids. Most greenhouses have adequate humidity. In the home, placing plants above moist pebbles in a tray is ideal.

Watering

The requirements vary with the type of plant. Generally, plants with large ﬂeshy roots or leaves need less-frequent watering than thin leaved or thin-rooted plants. Watering should be thorough and the medium should be dry at least halfway through the pot before watering again. This may be every 2-10 days depending on the weather, pot size and material, type of orchid and type of potting medium. Plants not actively growing should be watered less; many species have winter rest periods.

Fertilizer

Fertilize regularly while plants are actively growing. Applications of 30-10-20 formulations twice a month are ideal.

Repotting

This should be done when new growth is about one-half mature, Swansea, MA 02777 which is usually in the spring. Fine-grade potting media are usually used with ﬁne-rooted plants and coarser mixes with large-rooted plants; the standard size is medium grade. The plant should be positioned in the pot so the newest growth is farthest away from the edge of the pot, allowing the maximum number of new growths before crowding the pot. Spread the roots over a cone of potting medium and ﬁll in around the roots. FIrm the medium around the roots. Keep humidity high and the potting medium dry until new roots form.

Equitant and mule-ear oncidiums, as well as other ﬂeshy-leaved or large-rooted plants, can be grown on slabs of cork bark or tree fern or in pots ﬁllied with coarse, well-drained medium such as charcoal. This allows the drying between waterings that these types need.

Click here to download a printable PDF File




	Oncidium (on-SID-ee-um) This is an extraodinarily large and diverse New World genus with an equally diverse number of habitats. Oncidiums may origniate anywhere from sea level in the tropics to the high elevations of the Andes. This obviously makes cultural generalization diﬃcult. Some genera included are Aspasia, Brassia, warm-growing miltonias, and many of their hybrids. Temperature For this group, they are generally considered intermediate to warm, 55oF to 60oF at night, and 80oF to 85oF during the day. Temperatures up to 95o-100oF are tolerated if humidity and air movement are increased as the temperatures rise, a good general rule. Light Oncidium light needs can vary from bright to nearly full direct sun depending on the species. Most will thrive with one to several hours of sun a day. Generally, thicker-leaved plants, such as “mule-ear” and “equitant” oncidiums, can stand more light. In a greenhouse, 20-60% shade is required, or about 2000-6000 footcandles, depending on the plants. In the home, east, south, or west windows are good. Many types of oncidiums will grow under artiﬁcial light. Four ﬂuorescent bulbs and placed 6-12 inches over the plant are necessary for proper growth. Metal-halide and sodium-vapor bulbs also provide suﬃcient light without nedding to be so close to the plants. Humidity It should be between 30-60%. Many oncidiums require less humidity than other orchids. Most greenhouses have adequate humidity. In the home, placing plants above moist pebbles in a tray is ideal. Watering The requirements vary with the type of plant. Generally, plants with large ﬂeshy roots or leaves need less-frequent watering than thin leaved or thin-rooted plants. Watering should be thorough and the medium should be dry at least halfway through the pot before watering again. This may be every 2-10 days depending on the weather, pot size and material, type of orchid and type of potting medium. Plants not actively growing should be watered less; many species have winter rest periods. Fertilizer Fertilize regularly while plants are actively growing. Applications of 30-10-20 formulations twice a month are ideal. Repotting This should be done when new growth is about one-half mature, Swansea, MA 02777 which is usually in the spring. Fine-grade potting media are usually used with ﬁne-rooted plants and coarser mixes with large-rooted plants; the standard size is medium grade. The plant should be positioned in the pot so the newest growth is farthest away from the edge of the pot, allowing the maximum number of new growths before crowding the pot. Spread the roots over a cone of potting medium and ﬁll in around the roots. FIrm the medium around the roots. Keep humidity high and the potting medium dry until new roots form. Equitant and mule-ear oncidiums, as well as other ﬂeshy-leaved or large-rooted plants, can be grown on slabs of cork bark or tree fern or in pots ﬁllied with coarse, well-drained medium such as charcoal. This allows the drying between waterings that these types need. Click here to download a printable PDF File