There seem to be as many opinions on how to grow cattleyas in Melbourne as there are types of cattleyas. This is how I grow mine;
I HARD GROW all of my Cattleya orchids. Cattleya orchids that have been hard grown have bigger, sturdier blooms and the inflorescence tend to be stronger hence not requiring additional support (staking). The orchid plants are given outside conditions and as much orchid fertilizer they can handle. This 'wild state growing' shows up in the orchid blooms.
Temperate to Tropical. For mature plants, this ranges from 9 degrees Celsius in the winter to over 35 degree Celsius in the summer. I bring my young plants in over winter so that they are out of the cold and rain. This allows the plant to grow even in the winter months.
Any partly sunny or well lit position. Cattleyas on the whole need bright light to be able to bloom to their fullest potential. Consider several things when trying to provide the sufficient amount of light.
What season of the year is it? During late autumn, winter, and early spring, my cattleyas get 70% full sun (with only a mosquito net or 30% shade cloth protecting them from the direct sun). At this time of year, getting sufficient light means minimal shading. The sun's rays are not as intense and the added light allows the cattleyas to flourish. However - NEVER leave it out in direct sun. During late spring, summer, and early autumn, they need added shade from the intense sun, I use 50% shade cloth. To determine if you are getting the right amount of sun, inspect plants that you have had in the same spot for awhile (about 3 months). If the colour is dark green, then there is too much shade. If colour is light green (almost lemon yellow), then they are getting too much sun. If the leaves are stiff and strong, then they are okay. If they are soft, floppy and bend easily then they need light, water, or fertilizer.
More orchids are killed by over watering than from lack of water! It is recommended that you allow your mature cattleya orchids to dry out thoroughly before being watered again. In winter, I water once a week. Spring through to autumn, I water twice a week. Depending on how many >30 degree Celsius days we get, I will increase the watering accordingly. Please note; in spring through to autumn, I use a bamboo skewer to check before watering. I pick a pot, push a dry bamboo skewer into the middle, and let it set for 10 seconds. I then pull it out and touch my cheek with it. If the skewer is cool to the touch, I wait a day before watering. This method is not of my own invention, I learned it on the Internet. I always water thoroughly - until all the white roots turn green.
I've always been told to water first and then feed. Thinking about it, this does not make sense. Orchid roots are like sponges - they take up water and when they are saturated, they will not take up any more water. If you've already saturated the roots with water, how will the roots take up any fertilizer? I fertilize my orchids at half the recommended strength every watering.
I grow in open air with the orchids only protected by shade cloth, so when the humidity is below 50% I mist the plants. Do not over-mist until the water runs off the plant, because this is called watering. If you have a greenhouse, spray the floor very well and the evaporation increases the humidity in the growing area. Alternatively, leave repositories of water (buckets) to evaporate.
DO NOT remove a dried bud sheath, you have nothing to lose leaving it there. Some cattleyas, especially the late winter/early spring bloomers naturally produce and bloom from dry bud sheaths. The green sheaths are produced on the new growth the summer before, dry during the winter, and produce a bloom spike from the dry sheath in winter. Likewise, some Cattleyas do not need a sheath to bloom. The sheath is to protect the developing buds. Removing it may cost you blooms. I have heard of people peeling back the sheath so that the developing buds do not rot. If your buds rot - you are watering too much! You'll be suprised how much cattleyas appreciate not being disturbed.
Many cattleyas, when divided, will bloom the following cycle from the front division as long as there are 4 pseudobulbs or more. A back division will usually take two cycles to bloom.
When buying cattleyas, I have found that alot of them require some time to adjust to my growing conditions. Considering alot of them have come from Queensland (or a warmer part of the country), I find this quite reasonable. On top of that - I hard grow my plants and one would think it is reasonable some time is taken to acclimatise to their new environment. Give an orchid at least 2 years before you decide that it is a problem bloomer. If you are buying a mericlone, unless someone choose to mericlone a problem bloomer (wonder why people bother!), you would not generally expect to get a problem bloomer. After all, only show winners and plants with desirable characteristics (such as strong growth and flowers) get mericloned.
This is quite different from a problem grower! Be careful that you do not buy cattleyas that have been out of their growing medium for >2 weeks - without pointing fingers, there is a huge market in imported orchids which have 'grown up' in sunny tropical Asia. Notably, roots on such plants will be white and dry like hay. You will also not see any evidence of green growing tips on their roots. If you do choose to buy a 'recent import', you would need to 'restart' the plant, and that is a whole different discussion altogether.
Plants can be purchased in flower relatively expensively, and this is generally how new growers start. Small plants can take 4 to 6 years from seed to reach flowering size. You can grow from seed yourself, but contrary to the usual garden plants, seeds must be sown and germinated in sterile containers which new growers can find difficult. Also, the establishment of plants from the flasks, while an interesting challenge, can be difficult for those without experience of orchid growing.
Seedlings can be purchased, which will produce variable flowers even where the same parents are involved, reflecting the variation and quality of the parents. A group of seedlings can be interesting to grow, as you never really know what you are purchasing, and the variation in individual plants gives an added interest. Unfortunately, most breeders only sell what they do not want and keep the best seedlings for themselves. Alternatively you can also obtain as divisions from an adult plant althought this process can be slow as you can only get that many divisions from a plant at one time.
Mericlones have been a major factor in the improvement in the quality of many orchids and is an important type of source material. Mericloning is a laboratory technique that produces plants identical to the source material, and because they can be produced relatively cheaply, enables the widest distribution of identical high quality material.