HOW TO GROW ORCHIDS

The majority of orchid species are part of that specialist group of plants known as ‘epiphytes’. This is a group of plants - mainly found in the tropics - that have turned their back on growing in the ground and instead have made their homes up in the tree canopy.

Because of this, the roots of epiphytic plants have evolved to become more than just a structure used for support, and nutrient and water uptake. In the specific case of orchids they are also used for water storage and - rather impressively – to house chlorophyll pigment so that the roots can produce energy rich sugars through photosynthesis along with their fleshy leaves.

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As mentioned previously, in their natural habitat epiphytic orchids live high up in the canopy often secured to a suitable branch. Although this makes them safe from grazing predators it also puts them well out of reach from life giving ground water and the nutrients locked up within the soil. In order to obtain their essential nutrients orchids have to rely on accumulated debris, bird and animal droppings to be washed onto their roots by rain.

All of this means that when it comes to looking after and caring for orchids effectively, it helps to understand the environment they come from.

When buying a shop bought orchid you will notice two things.

1. The ‘rootball’ of your orchid is growing – I hope – in a clear container and,

2. Your orchid is not grown in compost but rather a course, free-draining bark substitute.

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The free-draining bark that the orchid is rooted in is there to prevent the root environment from becoming waterlogged.

It is also to mimic – as best as possible – their natural environment in which they are found to be clinging for dear life onto the bark of their host tree. The container is clear so that the orchid roots can continue to photosynthesis using the available light.
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There is a simple saying - although it's more of a generalisation -when it comes to looking after orchids which goes like this:

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However it is important to keep the free-draining bark compost moist all the year round so during the summer you may find that watering once a week isn't enough. When watering the plant, remove it from its pot cover – if it has one - and gently submerge the rootball. As soon as the rootball is completely submerged take it out of the water and allow any excess to drain away,

After 20 minutes or so place the orchid back into its pot cover. Remember to never allow the root ball to stand in water for extended periods as the roots are designed for growing in the air and can easily become damage. Allow the compost to dry out slightly and for the pot to become lighter before watering again. Avoid water collecting in the crown of the plant as this can cause fungal rots.

The way that orchids have evolved to cope in their nutrient poor habitat means that they do not need as much fertilizer as other house or garden plants.

Using the normal concentration of water soluble fertilizers that you would use for other plants will quite simply overfeed orchids burning their roots and leaves, and cause fertilizer salts to build up in the growing mix. This is caused by the phenomenon known as ex-osmosis. The dictionary explanation of osmosis is a follows:

Osmosis is the diffusion of water through a semi-permeable membrane, from a low concentrate solution (high water potential) to a highly concentrated solution (low water potential), up a solute concentration gradient.

Ex-osmosis occurs when water contained within the plants root is drawn back out into the root environment due to the high concentration of nutrients compared to that within the root. If exposed for too long the root cells will die through dehydration causing the characteristic burn marks on the surface of the roots.

Over-feeding orchids will not make them grow faster, or flower more, but instead will push them into decline and even die. However there are some basic orchid feeding rules with will prevent this from happening.

1. If using a standard house plant food always feed your orchids using half the recommended strength. If in doubt, always feed less.

2. Purchase and use orchid fertilizers specially formulated for orchids and simply follow the directions.

3. Try not to get into the habit of feeding orchids the same amount of feed at the same time each month. Orchids will need more feeding in the spring and summer months while they are actively growing, and far less during the cooler winter period.

4. You can’t treat all orchids the same and this includes the amount of fertilizer given. Give larger growing specimens or species that naturally produce more foliage – cymbidium species – more food than other those that grow naturally smaller or produce less foliage such as plants from the paphiopedilum family.

Together with feeding your orchid plants and to reduce the risk of over feeding it is also a good idea to flush the root system thoroughly with water at least once a month to get rid of excess salts.

Orchids won’t need to be potted on very often even though they may look as though they do. What does this mean? Well, orchids grow two main and distinctly different types of root - aerial and subterranean - and unfortunately (especially for the tidy minded) it is in their nature to send these roots everywhere looking for nourishment and more points to anchor themselves to.
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This can of course look untidy and you can be forgiven for thinking that the plant is doing this because they have exhausted the nutritional supply within the pot. However, don’t forget that when orchids are grown indoors they rely on the owner for adequate feeds with a soluble fertilizer and if the orchid is being fed correctly then there is no need to re-pot. With that in mind do not make the mistake of trying to bury aerial roots back within the confines of the pot because even if they don’t break in the process they will eventually suffocate and rot.

That being said there are times when you really will need to re-pot your orchid.

1. Orchids can outgrow their pots and this point is reached when there is room left within the pot for the next season’s growth.

2. Orchids will need to be re-potted in a fresh batch of appropriate sterilised compost if the existing potting medium is beginning to decompose.

3. Remove and re-pot the orchid if it is showing any sign of root rots.

4. Re-pot orchids if there are visible signs of salt residue on the growing medium

The best time to re-pot orchids is after they have finished flowering and have begun to produce new root growth. If you can, always try to avoid potting on orchids while they are in flower.

The best time to re-pot orchids is after they have finished flowering and have begun to produce new root growth. If you can, always try to avoid potting on orchids while they are in flower.

Gently squeeze the sides of the pot then tip the pot on its side and carefully remove the plant from the pot. Keep an eye on the base of the pot as you may have roots that have grown through the drainage holes. If this has happened then try to thread the roots back through the holes without damaging them. You may need to consider cutting the pot away from the rots in severe cases.

Once the orchid has been released from it pot, try to remove all trace of the old potting medium. Look over the root system and with a pair or sterilised scissors trim off all roots that are black, dark brown, or mushy. Scissors can be sterilised by either dipping them in methylated spirits or by passing the blades through a flame. All healthy roots will be turgid to the touch and white or light tan-brown in colour.

Remove any old, shrivelled or dormant growth that you can find - such as "back bulbs”. These are older, pseudo bulbs that have lost their leaves but are still alive. Once removed, these back bulbs can be either thrown away or potted on themselves. Dust all areas that have been cut with sulphur.

When it comes re-potting, choose a compost mix which has been specifically formulated for orchids, and allow it to soak overnight in water before you use it. With regards to pot choice tries to keep to clear pots and use a new one where possible. At the very least sterilise the old one with boiling water to kill off any pathogens before hand – don’t forget to let it cool down first!
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When ready, hold the plant inside the new pot keeping the base of the plant roughly where it should eventually rest, i.e. in line with the top of the compost. Now begin to drop compost around the roots, tapping the pot firmly as you do so – this will help to shake the compost down amongst the roots. When the compost is almost level with the leaves then you have finished although there may well be some gaps which you can see through the side of the clear plant pot, don't worry as the odd air chamber is beneficial to the plant roots.

When should you Re-pot an Orchid?
Images care of http://freebookessay.com/top-title/wild-orchids-f3ba71d326561db951353f5a4e6a45c1.html  and http://www.aos.org/Default.aspx?id=78 and http://www.aos.org/Default.aspx?id=78 and http://wannabe-florist.blogspot.co.uk/2012/02/post-harvest-and-repotting.html and http://wannabe-florist.blogspot.co.uk/2012/02/post-harvest-and-repotting.html