Oncidium Orchid Care in New Zealand
Oncidium orchids are a big group with many different types. Some grow in warm places, and some grow in cooler places. Because of that, care can change a bit. But most Oncidium orchids grow well in New Zealand homes if light, water, and potting mix are kept steady.
Light
Oncidium orchids can take bright light, and some types can handle a few hours of direct sun. Thick-leaved types (like mule-ear and equitant kinds) usually take more light than thin-leaved kinds. A bright east, south, or west window can work well in New Zealand homes. In a greenhouse, they often grow well with light shade.
Temperature
Many Oncidium orchids like intermediate to warm temperatures.
- Night: about 13 to 16°C
- Day: about 27 to 29°C
They can handle hotter days (up to about 35 to 38°C) if the air stays moving and humidity is higher. In New Zealand summer, extra airflow matters a lot in hot spells.
Water
Water needs depend on the type of Oncidium orchid. Plants with thick roots or thick leaves often need less watering than thin-rooted types. Water the pot well, then let the potting mix dry at least halfway down before watering again.
This might be every 2 to 10 days, depending on season, pot size, and the potting mix used. In New Zealand winter (June to August), many plants slow down, so watering is usually less often.
Humidity
Most Oncidium orchids do well around 30% to 60% humidity. Many need a bit less humidity than some other orchids. In a home, a tray with damp pebbles under the pot can help, as long as the pot is not sitting in water.
Fertiliser
Feed Oncidium orchids lightly and regularly. Use Superthrive Grow 7-9-5 or Superthrive Orchid-Pro 7-8-6 at 1 mL to 1.5 mL per 1 L of water. Feed once a week all year round.
In winter, the feeding gap may be longer than one week. It depends on how long the potting mix takes to dry out and how fast the plant is growing.
Potting
Repot when new growth is about half grown. This is often in spring in New Zealand (September to November). Use a finer mix for fine roots, and a coarser mix for thicker roots. Place the newest growth away from the pot edge, so there is room for the plant to grow forward.
After repotting, keep humidity up, and keep the mix a bit drier until new roots form.
For potting supplies, Kiwi Orchid Bark and Orchid Potting Mix can be purchased from Bio Leaf: Bio Leaf Premium Orchid Potting Mix and Kiwi Orchid Bark.
Some thick-leaved Oncidium types can also grow on slabs (like cork or tree fern) or in a very free-draining coarse mix, so they dry out more between watering.
Insect Control
Check leaves and bulbs often for scale, mealy bug, and aphids. If pests show up, isolate the plant, wipe insects off, and treat early. Good airflow helps reduce pest problems.
Disease Control
Most disease problems start when the pot stays wet too long and the air is still. Keep airflow steady, avoid leaving water sitting in the crown or leaf bases, and let the potting mix partly dry between watering. If rot is seen, cut away soft parts and dry the plant out faster.
Learn More About Oncidium Orchids
If they would like to learn more about growing orchids, think about coming to the next NZOS meeting. Meetings are a good place to see well-grown Oncidium orchids, ask questions, and learn simple growing habits that work in New Zealand.
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