Oncidium Sw.
Tribe: Cymbidieae
Subtribe: Oncidiniiae
Etymology: From Greek = Onkos.
Olof Swartz, in 1800, gave this name due to the small callus situated at the base of the lip which seams to be a wart, tumor, swelling, in Greek, Onkos.

 


There is no standard way to cultivating Oncidium. It depends on the origin of the species.




Some of them like strong light but never direct sun. Sometimes, it occurs in the nature however, in this case, there are some elements that counterbalance this condition.
Some species like average light or can bloom in lower light or higher light such as O. pumilum (nowadays Lophiaris pumila), O. jonesianum, O. sarcodes, O. flexuosum, O. lanceanum (nowadays Lophiaris lanceana). Some species like more luminosity during the winter and more protection during the summer such as O. phymatochilum. Some times, putting the plant just a few centimeters away, is enough to change the way of flowering.
 



In general, they love an alternation of wet and dry conditions.
The watering should be intense during the grow period since the news shoots until the maturation of the pseudobulbs. Keep the substrate moist but not soaked however for the so-called equitants (nowadays Tolumnia), the compost should not be allowed to dry out completely.
Some need a rest period which can be severe, some do not. However the reduction should not provoke a wrinkle in pseudobulbs and leaves.
In general, in south and southeast of Brazil, where the most part come, the winter is dry so during this period, in the nature, they do not receive much water only the mist of the night.
The cerrado (woodland savanah) and tablelands (chapadas and campos de altitude) are also very dry during this season. The species which come from Atlantic Forrest need more humidity than those which come dry region.
Reduce water when blooming.



 

In hotter regions, we can apply fertilizer all year round, but in cooler climate it seems not to be desirable. In this case, in my opinion, we should not fertilize during the second part of the autumn and during the winter. I live in Brazil, in Rio de Janeiro, so the climate of my region is hot and during the winter the temperature is just more agreeable and, in general, I apply weekly a foliar balanced fertilizer (10-10-10, 7-7-7) for three times. The fourth, I apply a phosphate fertilizer to induce flower. Three months before the blooming season, I invert this application and use for three times the phosphate fertilizer and the fourth I apply a balanced one.


 

Some species can be cultivated under every condition such as
  O. ciliatum - Archive/Arquivo: Carlos Eduardo o Oncidium flexuosum,
o O. ciliatum,
o O. bifolium e
o O. baueri
  but, in general, the species are not very tolerate to a inadequate conditions of temperature indicated to its cultivation.
A plant which comes from a cool temperature, such as Oncidium crispum or O. concolor, cultivated in warmer conditions, will bloom and perhaps grow in a reasonable way for 2 or 3 years. Then, suddenly, it will become weak and die with no apparently reason except for being cultivated under inadequate temperature. So, choose species or hybrids according to the temperature you have:
  O. baueri,
  O. cebolleta - Foto/Photo: Sergio Araujo O. cebolleta,
  O. ciliatum, O. flexuosum, O. fimbriatum
  O. lanceanum - Photo/Foto: Sergio Araujo O. lanceanum(nowadays Lophiaris lanceana),
  O. macropetalum, O. micropogon,
  O. morenoi - Photo/Foto: Sergio Araujo O. morenoi (nowadays Lophiaris morenoi),
  O. nanum (nowadays Lophiaris nana), O. sarcodes, between others, can be cultivated under warmer temperatures, without problems.
  Under intermediate to cool conditions, choose:
  O. cheirophorum,
  O. cornigerum - Photo/Foto: Sergio Araujo O. cornigerum,
  O. crispum - Archive/Arquivo: Carlos Eduardo O. crispum,
  O. cruciatum - Archive/Arquivo: Carlos Eduardo O. cruciatum,
  O. curtum, O. divaricatum,
  O. forbesii - Archive/Arquivo: Carlos Eduardo O. forbesii,
  O. gardneri, O. hastilabium, O. lietzei, O. pubes, O. ornithorhynchum, O. pulvinatum, , O. robustissimum, O. sarcodes, O. sphegiferum, O. varicosum, among others. The species of the Cyrtochila section (nowadays, considered as a independent genus, Cyrtochilum) and of the Cucullata section (High altitudes of the Andes) require very cool condition to be cultivated and need less light than the other species. O. carderi, O. falcipetalum, O. lamilligerum, O. macranthum, O. orgyale, O. serratum, etc.. (nowadays Cyrtochilum carderi, C. falcipetalum, C. lamilligerum, C. macranthum, C. orgyale, C. serratum) e O. cucullatum, O. dayanum, O. olivaceum, O. phalaenopsis, O. rhodostictum, etc.




As many other genera, Oncidium loves a light breeze in order to ventilate its roots but it does not like strong wind which can dry out completely its roots and makes them shrivel.
See Data Center where you will find some species and hybrids with indication of the way to cultivating them.





Oncidium can be cultivated in many containers, tree fern slabs, cork bark, logs, alive trees, plastic and earthenware pots with tree fern fiber, coxim or conifer bark.
  The species with creeping rhizome such as
 
O. crispum - Archive/Arquivo: Carlos Eduardo
O. varicosum - Archive/Arquivo: Carlos Eduardo
O. forbesii - Archive/Arquivo: Carlos Eduardo
 
Oncidium crispum,
O. varicosum var. rogersii
and O. forbesii
  will grow well in soft tree fern slabs. To provide more moisture, when cultivated in slabs or logs, put in a perpendicular position.
The best time to repot it is when the news shoots start. This moment can come just after the bloom period or months later, depending on the species.
It is very important not to disturb the plant when it is blooming or during the rest period.
  The best time to repot it is when the news shoots start. This moment can come just after the bloom period or months later, depending on the species.
It is very important not to disturb the plant when it is blooming or during the rest period.