Fat psuedobulobs on oncidiums

[jmateosky]

Hi,

I attached a photo of one of my oncidiums it happens to be a sweet sugar. my oncidiums (sherry baby, wildcats...). all seem to have the same problem the grow big FAT psuedo bulbs, but often the don't like to flower. It is like the are to busy growing and haven't been induced to flower, or something. Do they need a rest period, dry period? It is like I am over feeding them? but he plant looks increadable healthy. Any Ideas?

I grow various catleyas and they grow nicely, and flower nicely as well.

[fred]

just some information I have found for you.
I hope this helps you.

Oncidium is a wonderful genus for orchidists since it contains sufficient numbers and in such a diversity of plant habit and floral features that a grower can spend a lifetime collecting all the variants and learning how to grow them.

Numbering more than 750 species, these orchids are distributed in South Florida, Mexico, the West Indies, Central and South America. Ranging from the lowlands to high elevations in the mountains, most species grow as ephiphytes on trees and rocks with a few being terrestrials.

Some distinct growth habits can be readily recognised within the genus. One group, the equitant species, lacks pseudobulbs and has iris like growths of divergent leaves closely overlapping at the base. Another group, dubbed by growers as 'mule-ears' have large, thick leathery leaves.

CULTIVATION

Oncidiums are generally regarded as being an adaptable group of orchids but even so consideration of their area of origin can help to avoid problems. Those species from high elevations are cool growers whereas those originating from the low lands require heat. Light and water requirements seem to be related and vary somewhat with the group involved.

Those species which have tall, pear-shaped pseudobulbs are in continual growth throughout the year and need to be kept continually moist and do not have a high light requirement. Terete-leaved species, those with very small pseudobulbs and those with nearly round pseudobulbs should be allowed to dry out between waterings (every two or three days). They will also tolerate bright light but if the leaves begin to turn red, then reduce the light intensity.

Most species of Oncidium are grown in pots but some suffer badly from root rotting and are much better on slabs. Under potting is better than over potting. Buoyant air movement is important to these orchids which as a general rule do not require high humidity.

Bark culture is best suited to those orchid species which produce one pseudobulb some distance above the previous one, a long upward growing rhizome joining them. Orchids are grown in pots for convenience, but culture on bark is much closer to their natural mode of life.

Orchids growing on bark will require rebarking (bow-wow) at regular intervals, a plant can remain on a piece of bark or branch of a tree for several years, depending on the length of material. If a plant outgrows its piece of bark by growing continually upward, it will not affect the plant, provided that it is given sufficient moisture by regular spraying and has plenty of aerial roots from the newest pseudobulbs. However, there comes a time when it is necessary to remove the plant from the old bark, and place on a new piece of bark or branch. Having carefully removed the plant from the bark, the dead roots or pseudobulbs can be removed. One advantage of bark culture is that there is hardly any disturbance to the plant and its entire root system can be left intact; there is no need of root trimming. Even roots slightly damaged during the rebarking operation can be left on the plant. Exposed to the air they will simply heal themselves and continue to grow.

A pad of sphagnum moss is place for the whole length of the plant, which is placed with the oldest part of the plant to the bottom. There is no danger of over-barking but a long slender piece of bark is better than a broad piece.

Mounted Oncidiums

This means securing your plants to either a tree fern, cork slab or piece of wood. Put the plant as close as possible to the bottom, (the plant likes to climb upwards) and place a small amount of Sphagnum Moss under the roots. This will help keep the slab moist and encourage the roots to attach themselves to it. Tie the plant firmly to the slab to avoid movement of the roots. Deciding whether to use tree fern, cork or wood should be no problem. Cork you can use immediately, wood if new, requires a good soaking for about 3 months to remove the sap. Tree fern need at least a year to prepare for use. If you decide to use tree fern, use the black one not the brown, which contains too much acid which will kill the roots. To treat it you will need to soak it for about 3 weeks in a bucket of water to which you have added a good handful of garden lime. After 3 weeks hang it up somewhere in the garden for 12 months. The rain and sun should kill any acid that is left.

Put your plant close to the bottom of the slab. As the roots start to grow, keep your eye on them. If the green tip starts to go black, remove the plant, hang up the tree fern as there is still acid in the slab.

If you have an Oncidium which has a nice bulb and green leaves but has lost its roots, don't throw it away. Remove any remaining dead roots from the plant and secure it to a mount, spray the leaves with water every day and with weak fertiliser once a week. As soon as Spring arrives, 98% of the time, a new lead will grow and the roots will follow.

To remount an Oncidium

When the Oncidium has reached the top of the slab, do not try to pull the plant off as it will probably die. First, cut back the plant 3 bulbs down from the top of the plant and powder the cut with Sulphur. The following Spring the new lead will start to grow and all being well, a lead will grow from a bulb below the cut. Now this is the time to cut the mount. Saw the mount where you made the back cut - this must be done before the roots begin to grow. Put both pieces in pots with the mounts attached, fill the pot with bark to hold the plant steady and spray the roots regularly. The following year the new lead will be high enough to re-establish on a new mount.



CULTURE


There are warm growing Oncidiums, some of which are called tolumnia and mule eared. There are also a number of the thin leaf variety which require warmth in winter. The mule ears have thick leaves shaped like mule ears. They have no pseudobulbs. The Tolumnia have leaves which are narrow, thick and slightly grooved. They too have no pseudobulbs.



The cool growing Oncidiums have thin leaves and pseudobulbs and their flowers are mostly yellow and browns. They can be grown in most areas of Australia provided they are protected from cold winds, frosty nights and prolonged low temperatures. In the cold areas, they are better grown in a greenhouse. Try to provide them with the same environment they would get in their natural surrounds. Fresh air, plenty of water when needed, weak fertiliser and most of all, protection from the sun.


Winter

There isn't much movement by the plants, just a couple of live roots, plenty of dead looking ones. Some plants have no live roots at all and the bulbs are shrivelled. Don't panic, this is quite normal for this time of the year. Leave in the shade house all through the winder, unless there is more than 6 hours of rain. Then put them under cover until the rain ceases, then place them back out again. The exception to the rule are plants in pots and those on tree fern. They need to be under cover all winter. Just spray the leaves and any roots on top of the bark and any aerial roots. If it is a nice sunny day, spray all the plants with water first and then with a weak fertiliser.

Spring

Because the weather is unpredictable, it is not possible to tell when or how often to water your plants. If it is cold and raining, don't water. When it is warm, water. The warmer the days get, the more the plants require water remembering to allow the roots to dry out between waterings. Around October, the plants will send out their new leads and the roots will start to appear even little roots pop out of the dead looking ones. As the weather warms up, increase watering and fertiliser to half strength twice a week. The plant on the tree fern can now have the same treatment as those on cork. Plants in pots need to have the roots sprayed as they start to grow and require fertilising the same as those on slabs.

Summer

The heat and hot winds can be very stressful for Oncidiums so keep them in the shade house during Summer. The warmer the weather becomes the more the plants get watered and fertilised. If the temperature rises to 30c and above, wet the floor and lower the plants nearer the floor. It is also a good idea to place some Old Man's Beard or Sphagnum Moss around the roots at the beginning of Summer as this will help them from drying out in the heat. Do remove the material placed around the roots at the end of Summer. Some time in February, the flower will spike. Don't spray late at night in case water gets down the leaf where the spike is.

Autumn

The weather can still be very hot, so water and fertilise accordingly. The flower spike should be quite long now so keep a watch out for greenfly and caterpillars. Spray with soapy water for greenfly. If you use pure soap, it won't harm the flower buds. Use your fingers and feet for caterpillars. If it rains, put the plants in flower under cover to protect the flowers.

[jmateosky]

fred,

That was an excellent post great info. But I still have my question why are my psuedo bulds so fat, the look pregnant. I go to other greenhouses and every other plabt I see has shriveled psuedo bulbs?

Jim

[fred]

Is your plant kept in the same growing conditions as the ones kept in a green house ?
By the look of your plant I would say no as your plant looks to be in good health. ( by the pic )
as your plant looks to be in good condition i would not worry to much.

[mayres]

The size and thickness of the pseudobulbs is genetic to some degree - different crosses and genera will have different 3D shapes. Another factor is the humidity and other conditions your orchid is currently (or recent history) been in. When in ideal/good conditions the plant uses those pseudobulbs to store up water and nutrients for potential days in the future when it might not be quite so good. Enjoy! mike

The fat p-bulbs indicate that the plant is getting enough water, and oncidiums like lots of water. If the plant hasn't bloomed, it may need a bit more light and a fertilizer with less nitrogen. I take my sweet sugar outdoors in the spring where it gets good morning sun and then very bright light the rest of the day and it blooms like crazy. Also, the pot looks too big for the plant. The pot should only be big enough to accommodate the roots and a tiny bit more for growing. I find my sweet sugar blooms better when potbound. I repot it every other year, and only if I have to.

[Ellen]

What orchid 126 says. More light and less fertilizer and I bet your oncidium will bloom like crazy next fall.