วันพุธที่ 12 มีนาคม พ.ศ. 2551

Disa Orchids


Growing Disa Orchids Introducing Africa's Disa Orchid
Cool growing 7 - 20 C (45 - 68F)

Disa orchids are native of South Africa and despite the hot climate of their home they are actually cool growing orchids, if not alpine as they hail from high altitude areas on mountain tops and grassy mountain slopes. This is good news for you and me as it means that they are easily kept amongst your collection of other cool/cold growing orchids like Odontoglossum, Coelogyne, Cymbidium and Pleione.

Although there are over 130 species of Disa available, by far the most commonly grown is Disa uniflora (which is native to Table Mountain near Cape Town) and cultivars stemming from this species. Disa uniflora has the largest flowers in the group in the richest reds to be found in any orchid. There and lots of crosses with blooms from pale yellow through deep crimson. The Disas in the uniflora group and their hybrids are typically evergreen and are tuber based plants which produce flowers borne on 15 - 20 inch tall stems carrying between 3 and 7 flowers up to 3 inches across. They are excellent as cut flowers and will last well if kept in water.

Flowering normally begins in late spring and can continue until early summner.Fortunately for us they are also one of the fastest multipliers of all orchids. Having spoken to, and seen his collection, Howard Taylor of Yorkshire (one of the UK's leading experts in Disa orchids) tells me that from pollination to seed production can be as short as 5 weeks and that seed, unlike 'normal' orchids which has very specific germination requirements can be sown directly on to sphagnum moss compost mix with exceptional results. Flowering size plants can be had in just 2 years - almost a biennial


Lighting & Air for Disa Orchids

Disa orchids like plenty of light but not strong, harsh light, you should provide 30% - 60% shading during the summer and allow more light in the darker months. Disa like good air flow and so can be kept out of doors during the summer and early autumn, suitably shaded of course. Alternatively place an oscillating fan in the greenhouse to keep the air constantly moving and thus preventing stale pockets of air, oscillating fans are better then a strait forward one as they don't cause permanent draughts on one plant.

Disas like a good supply of fresh water all year round and the compost should be kept moist at all times. Water the pots every three to five days in warmer weather and every 7 to 10 days during winter. If possible use rainwater or if your rain is contaminated use boiled, cooled water.

Feed Disa orchids with general purpose fertilizer at quarter strength from March till September at which time you should begin feeding with a higher potash feed at quarter strength to help harden the leaves and stems ready for the cooler winter. In both cases apply the feed at every second to third watering making sure to flush the pots at least once a month with fresh clean water to remove any excess salts. Cease feeding in late October and resume the following March.Disa Compost

Compost for Disas needs to be well drained but moisture retentive, a good mix would be 40% sphagnum moss, 55% sphagnum pet plus 5% vermiculite to help keep it open. This will allow the compost to retain plenty of water but still be free draining which is a MUST with these plants.

Not all Disa orchids produce large plants. This diminutive plant with stunning bright yellow flowers is the miniature species Disa Aurata and is easy to accomodate in even the fullest collection!

Disas are easily propagated by potting up any loose tubers or side shoots that have developed during the previous season. Newly potted tubers will be flowering size in 1 - 2 to years depending on the size of the tuber/side shoot which should be removed and potted in the standard mix AFTER flowering, in the UK this means June/July.Remember, These orchid MUST remain damp at all times!


Dendrobium Orchids


Growing Dendrobium Orchids - nobile types Dendrobium - Nobile types
8 - 25 C (40 - 80 F)

Dendrobuims are often one of the first orchids that are attempted by growers new to orchids, and with good reason. A single plant can have hundreds of delicate white blooms with pale purple edgings and a deep maroon centre covering the whole pf the previous years stems (canes), they also come in yellows and pinks. These Nobile type orchids mostly come from South East Asia and the Himalayas and live at fairly high altitudes. Although this type of orchid are easy to grow there are a couple of things you MUST do if you want to see the annual display.

Light requirements

Dendrobiums like good light at all times but they should not be kept in full sun or they may scorch. Keep them in the brightest position during the winter months to help ripen the current years stems, called canes

This is one of the key elements that new growers often fail to provide - NO WATERING from mid November until February, if your atmosphere is very dry e.g. in a central heated home, dry greenhouse then you can mist your plants once a months to avoid over drying them or give them a good SINGLE soak every 8 weeks. The Nobile type Dendrobiums MUST have a rest from water between these dates if you want to see flowers. There is a fine balance between drying them out completely (killing them) and keeping them alive. This is due to their natural habitat in South East Asia where the winters are cool and the air fairly dry. This winter treatment is stopped in February as growth re starts and water should be applied sparingly until good roots are visibly growing from the new shoots, by June watering can given twice weekly and continued until November. This watering regime is due to the plants native environment where they would be subject to monsoon type downpours during the early to late summer with corresponding higher temperatures and humidity and cool dry winter conditions.

Since you will not be watering your Nobile type Dendrobiums during the winter you will not be feeding them!, from late March to September you should water with a half strength high nitrogen feed to boost growth and from September to November change to half strength high potash feed to ripen the canes.

Repotting and dividing should be undertaken in the spring either immediately after flowering or just as new growth starts. These plants need the roots confining and should always be under potted rather than over potted as this will help prevent over watering. These plants produce an enormous amount of aerial roots and so are ideal candidates for growing in many ways other than pots. They can be mounted on cork bark or even grown over a tree stump, they will become top heavy though but thanks to the abundance of anchoring roots should be stable by the following season after mounting.

Dendrobium - NON Nobile types
12 - 28 C (53 - 82F) Dendrobiums in this temperature range vary widely depending on where they naturally come from. They vary in size from a few inches high to several feet and have flowers ranging from tiny half inch flowers to whopping 4 inch blooms in a wide variety of colours. Dendrobiums come in two types here, deciduous and evergreen. The deciduous types will by November begin to lose their leaves after the very top final leaf (apex) is fully ripe. They also need much cooler conditions during this rest period and it can be allowed to drop to a minimum of 10 C (50 F) for a few weeks during the coldest part of the winter, this will in fact encourage flowers to form instead of young plants where flowers would have been.

Dendrobiums like good light at all times but they should not be kept in full sun or they may scorch. Keep them in the brightest position during the winter months to help ripen the current years stems, called canes.

This type of Dendrobium come from New Guinea and Australia - with a few exceptions. Generally speaking they require more water than their cooler growing cousins and will benefit from being watered once a week from April to October. From October through February/March start giving less water as at this time of year they are not actively growing.

Do not feed Dendrobiums during the winter as they are not actively growing and a build up of unused plant food can burn the roots, from late March to September you should water with a half strength high nitrogen feed to boost growth and from September to November change to half strength high potash feed to ripen the canes.

Repotting and dividing should be undertaken in the spring either immediately after flowering or just as new growth starts. These plants need the roots confining and should always be under potted rather than over potted as this will help prevent over watering. These plants produce an enormous amount of aerial roots and so are ideal candidates for growing in many ways other than pots. They can be mounted on cork bark or even grown over a tree stump, they will become top heavy though but thanks to the abundance of anchoring roots should be stable by the following season after mounting.

Cymbidium Orchids


Growing Cymbidium Orchids

Cool growing orchids need a minimum of 7C - 10C (45 - 50F) during the winter and a maximum of 24C (75F) during the summer Cymbidiums - mothers day orchids

This is one of the most often seen orchids and is found in bridal bouquets quite often as well as being given on mothers day, these are the ones you see in a little box containing a single bloom in a tiny jar filled with water. These orchids can be difficult to flower as they are often over cared for!. Cymbidiums are native to China, Japan and other areas of the region, require cool nights during the summer and a definite rise in temperature during the day of at least 5C (10F) if you want to see flowers rather than a plant pot of sword like leaves. They do not like draughts or extremes of temperature and are best kept out doors in a bright position but not in direct sun during the summer and early autumn - they must be kept frost free though otherwise they WILL die.


Light requirements

Cymbidiums like high levels of sunlight but not directly otherwise the leaves will scorch. Keep outdoors in summer (May - Sept) and in a well lit position indoors during the winter, avoiding the direct rays of the sun.

These plants have very thick roots which have a sponge like quality; useful during the summer months as a reservoir for the plant but not so useful during the winter when over watering can be disastrous if they are kept cold and wet. Water during the winter at 10 - 14 day intervals and water them by flushing the pot through with tepid water - not cold from outside or the tap as this will shock the roots. During the summer months they can be watered a couple of times a week in warm weather, less often if it's cooler. Don't be tempted to give a 'little drink' to your plant because it is damp and not quite dry as they don't like it - give it a couple more days and give them a good flush through. This also helps to flush out any unused plant food.

During the winter months feed the plant no more than once a month otherwise the roots may be burns by unused plant food. From spring to mid summer feed them every 2nd or 3rd watering with a high nitrogen plant food which will encourage strong growth and big pseudo bulbs to develop, from mid summer through to the following spring use a high potash feed to harden the pseudo bulbs and encourage more blooms.- Dilute the plant food to half to a quarter the recommendation your pack suggests.

Cattleya Orchids


Growing Cattleya Orchids

Cattleyas and closely related Laelias - pron. cat lee ya and lay lee ya
Intermediate 12 - 28 C (53 - 82F)

Cattleyas and Laelias are amongst the most flamboyant orchids around and are often referred to chocolate box orchids due the fact that they are often depicted on such packaging. These orchids are endemic to the central American rainforest growing along side the Poison Arrow Frogs, Bromeliads, luscious Passion Fruit and Papaya right through Brazil the Andean region. Mostly the plants are epiphytic (grow on trees) or Lithophytes (grow on rocks). Since they come from a very wide range of growing environments ranging from tropical jungle through almost freezing night time conditions you should be able to house one or two in your collection regardless of your conditions. Both types have stout bulbs usually with a single leaf at the top of the bulb which, when ripe is capable of producing from 1 to 4 very showy flowers in a variety of bright colours.

Light requirements

These plants like good light but not direct sun and will tolerate light shade during the summer months but none during the winter.

Watering requirements

Both Cattleyas and Laelias like plenty of water and humidity during the growing season with a rest from watering of between 6 - 10 weeks after the plant has finished it's current years bulb, this rest period will encourage the bulb to harden and help with flower bud formation. Often these plants are often over watered and the best rule of thumb is if in doubt, wait a couple of days.

They are quite tough plants and will not be harmed by missing a watering but will be harmed if over watered. Water once a week during the summer and once every two to three weeks at other times (other than their rest period) mist with fresh water once a day and damp down the benches to help elevate the humidity levels.

Feed once every two weeks from March to September with a half strength high nitrogen feed to boost growth and from September to mid October use a half strength high potash feed to ripen the bulbs, the plants should not be watered during mid October through to the following March.

Repotting should be undertaken during the spring months if they have out grown their pot or basket. Since they are epiphytic or lithophytic they can be grown in baskets or on rafts of wood or cork bark, If using pots use a large grade bark compost as this will allow the roots to penetrate the compost and prevent them from being waterlogged.

fuji camera