Oncidium excavatum

Also known as: The Hollow Oncidium in the subfamily: Epidendroideae

Native to: Cajamarca - Peru Ecuador

General Information

The Hollow Oncidium is a large sympodial cool to warm growing epiphytic or terrestrial orchid belonging to the sub family Epidendroideae native to Peru and Ecuador. The name refers to the deep pit at the base of the underside of the lip.

Plant Description

Sympodial. Grows to 40-100cm. Each new growth has numerous oblong shaped leaves that grow to 2.5-50cm long. Pseudobulbs grow to 7-18cm

Substrate(s)

• Coarse
• Bark
• Charcoal
• Spaghnum Moss
• Perlite

Care Notes

These orchids like to be kept on the dry side, but may need to be watered daily during warm weather, and prefer a well draining mix or also do well mounted, provided they can be watered regularly.

These are quite a forgiving orchid, there are no special requirements to get this orchid to flower, just good care and consistent conditions. Larger plants may be more fussy and can react poorly to change; a poorly timed repotting, a pest infection or an unusually hot day can set them back for a couple of years. However, even plants that have been treated poorly can thrive, and if they are set back they often recover much stronger then they would otherwise be.

Climate

Grows at high elevations. Rainfall ranges from 23mm to 109mm per day, heaviest in October and lightest in January. Humidity ranges from 73% to 77%, highest in October and lowest in January. Temperature ranges from 7C to 21C, highest in May (10C to 21C) and lowest in February (7C to 18C).

Fertiliser

Apply liquid based fertiliser per recommended directions. They can benefit from a high phosphate fertiliser leading up to flowering season, followed by a high nitrogen fertiliser when new growth appears, and a balanced fertiliser in other times. These orchids can also tolerate slow release fertiliser applied 1-2 pellets per cup (250ml) of media.

Use balanced fertiliser during Summer. Be sure to flush out excess fertiliser by running water through the media regularly year round. Apply fertiliser regularly at half strength year round. Use a low Nitrogen fertiliser during Summer. Use a high Phosphorous fertiliser during Summer. Reduce fertiliser when plant is dormant during Spring.

Potting

These plants can be sensitive to repotting though should not require repotting regularly. Repotting should be done when the mix has broken down to the point that it doesn't absorb water or holds onto water for far too long, usually the plant shows a decline in growth as well.

The mix should be free draining, with a blend of 30% inorganic ingredients such as coarse sand, gravel or perlite, mixed in with about 70% organic ingredients such as peat, leaf litter or decomposed bark. Avoid commercial potting mixes as they can vary wildly and may contain "wetting agents" that can hold onto water for loo long, causing rotting and stunted growth.

This plant does well mounted. Repotting is best done annually and in a pot the same size or only slightly larger than the previous one.