Cultural Notes – Cattleya

Pronounced KAT-lee-uh, this group of orchids originate from a large area of tropical and sub-tropical America. They occur in many sizes, shapes and colours but are best known for their large flamboyant blooms. Most grow as epiphytes, or air plants. They have large pseudobulbs used to store water and have thick, fleshy roots that have the ability to collect moisture from the air.

Light is important for good flowering. About 50% is optimal, however if leaves overheat in summer this may need to be increased to 70%. Leaves should be medium green colour and pseudobulbs rigid and erect without staking. Excessive shading will reduce flowering dramatically and lead to soft, floppy growths.

Temperature should range between a minimum of 5-7° celcius in Winter to a maximum of about 30°-35° in Summer. I suggest you avoid watering if the temperature falls below 10°. Small plants need to be protected from temperature extremes. High day temperatures, up to 35° can be tolerated if humidity, air circulation and shading are increased.

flitter can be provided in two ways, in the pot by watering and in the air by humidity. For a plant growing in good open media, watering twice each week in Summer and once per fortnight in Winter is sufficient. In Summer avoid watering during the heat of the day, in Winter only water on a bright sunny morning. The root system on these plants can easily be damaged by excess water. If in doubt, defer watering.

Humidity is important to Cattleyas as roots prefer to grow in humid air rather than to be wet. Humidity needs to range from 50% to 80%, about 60% is ideal. In Winter watering can be delayed by wetting the greenhouse floor and circulating air around the plants. This technique can also help to cool the plants in Summer. If you live in a Southern Winter rainfall area, it may be neccessary to grow your Cattleyas under a solid cover so watering can be controlled during Vinter.

Fertilise with a complete balanced NPK fertiliser for flowering plants. Apply fertiliser with the water every second watering, this may mean every week in Summer and once or twice per month in Winter.

Pots & Medium. Pots should be shallow; ie width greater than the depth, & should have plenty of holes to allow perfect drainage. Media needs to be coarse and long lasting. OrchidMate coconut husk chips, treated pine bark or graded charcoal is ideal. As a guide, use medium grade (10mm) in 100min pots, large grade (15mm) in 150mm pots & extra large grade (20mm) in 200mmm pots or larger.

Pests & Disease. Cattleyas, apart from root rot caused by overwatering, can be attacked by pests such as scale and mealy bug. Check under dead bracks on old bulbs for hidden scale. This is easily controlled by Rogor or Pest Oil. Slugs and snails love fresh root tips, as do cockroaches, so check for these pests if root tips are being damaged. Hanging plants or growing on mesh benches can help, but snail bait may be necessary.

Tinonee Orchid Nursery