The cultivation of an orchid is delicate and requires skill, especially when repotting is necessary. No question of injuring its roots or installing it in an unsuitable substrate, for example. The choice of pot is also important. Here is everything you need to know to repot an orchid in the rules of the art but also at the right frequency and no more because let’s face it, this sublime plant does not like to be jostled at all.
Repotting an orchid: ideal period
It is best to repot an orchid in spring or in autumn and of abstain during other seasons.
The right time can be determined by observing the plant. Firstly, flowering must be over. On the other hand, if it presents new shoots and these are only a few centimeters tall, it is the right moment. Once the plant is repotted, new roots will appear. Anchoring them in the brand new potting mix will be much easier. Nonetheless, it is essential to adapt to the rhythm of his orchid. So it is she who chooses the best time to be repotted and not the gardener.
It should be noted, however, that this type of plant may need to be repotted in the middle of summer for various reasons. In this case, it is absolutely necessary to abstain during a period of heat wave.
Repotting an orchid: the different steps
It is not in two steps that we proceed to this delicate task. On the contrary, it is necessary follow the different steps necessary before, during and after repotting.
Choosing the Right Potting Mix
Specialists use, for example:
- Conifer bark,
- shards of glass,
- Lava in small pieces,
- sphagnum moss,
- Charcoal that has not undergone any treatment,
- coconut fibers,
- polyurethane foam,
- Polystyrene in fragments.
Some of these components can be combined to form what is called the potting mix perfect for orchids. But (with some exceptions) we do not use a substrate containing fermentable decomposed materials such as compost, potting soil or even earth which are in no way suitable for orchids. Except for the brown peat but on condition of putting one tiny amount. Brown peat is well suited for mini Phalaenopsis for example.
Whichever component is chosen (among the best suited only), it must allow a very moderate water retention. It is therefore a plant support more than a real substrate. Care should be taken to opt for a light mixture that does not risk suffocating the roots of the orchid.
Preparation for repotting
- The day before unloading, moderately wet the potting mix, or at least a few hours before.
- Let it drain quietly.
- Pass the blade of the pruning shears that will be used to cut certain roots over the flame of a lighter so as not to risk transmitting any disease to the plant.
It is very important to thoroughly disinfect the blade of the shears under a flame between each orchid if several are to be repotted during the same session.
- Unpot the orchid. The operation is more or less easy. You should know that the moreadhesion between the roots and the growing medium is strong, the better because it proves that the orchid has a root system in excellent condition. We must take off the roots of the support by compressing the pot a little but if nothing happens, it is better to cut the container with a pair of scissors rather than mistreating the roots.
- Remove leaves that are beginning to wilt and those that are dry.
- Thoroughly remove all the old substrate so that none remains even in the heart of the root ball.
- Discard this mixture which must not be reused.
- Scrupulously examine the roots of the orchid after gently disentangling them. All those that are in poor condition should be cut, namely rotten, dry, damaged roots. We only keep the green and light gray ones, which are very healthy. It may be necessary to pass the roots under running water beforehand in order to get rid of the brown peel juice which coats them so that this rinse reveals the true real color of each root.
- Soak the roots in water at room temperature for about fifteen minutes to soften them if they are stiff. This will allow them to be inserted into their new pot without damaging them.
- Select a pot new of sufficient size (it should not be too big) or take a pot that you have already used but disinfect it well. It is important that his fond that is pierced with several holes. A transparent pot is not an obligation, but it is very practical to check at a glance the state of the roots over time.
- Place 2 cm of draining mix for orchid on the bottom of the container, such as small gravel, pieces of polystyrene, clay balls.
- Install the orchid in its new pot, ensuring that the collar is 1.5 below the top level of the container. Pay attention to the position of the orchid because it is necessary take his species into account to place it correctly, namely:
- The rear part against an edge if it is a species with sympodial growthwith rhizome, whose pseudobulbs ensure the reserves of nutrients and water (Cymbidium, Murder, Dendrobium…),
- In the middle of the container if it is a monopodial specieswhich therefore produces only one shoot (Vanda, Phalaenopsis, Angraecum…).
- Hold the plant with one hand and with the other add potting mix to fill in any gaps.
We’re fine-tuning compacting in one place so as not to cause injury to a root, then more potting mix is added until the pot is very full and the voids perfectly filled.
If the repotting of the orchid is properly done, you should be able to grasp the plant by its leaves without it coming out of the pot. Otherwise, it means that the mixture is insufficiently tamped. There is a good chance that after a few days the plant will topple over due to its poor anchorage. It may therefore be necessary to start over, but it would have been better to do it the first time because this type of manipulation is not to satisfy an orchid!
The pose of a tutor can, however, help maintain an insufficiently anchored rhizome orchid in its new pot. The canes of the plant are then held to the stake with raphia for example. In the absence of a tutor, one can very well resort to pieces of to do that you bend so that they take the shape of a U. Then you just have to pass them over the roots and push the ends of these makeshift hooks into the potting mix for a better anchorage.
Thereafter, for at least 20 days, you should not water the orchid as you usually do, but you are satisfied every morning with spray very lightly the surface of the growing medium so that only the area located around the collar be moistened. This sort of temporary withdrawal is important because:
- It allows new roots to grow quickly. It is enough to spread a little of the surface substrate to see them.
- This prevents old roots more or less injured by repotting and/or preparation pruning from rotting due to wetting of the wounds. The usual watering can therefore only resumeafter complete healing and only if the new roots are found to be at least 4 cm long.
All that remains is to take good care of your orchid during 2 to 3 years before repotting. A period which must be shortened as soon as a large part of the roots rots, or if these are burned by dint of having been watered with very calcareous water. But we do not forget that we never repot an orchid when it is in full bloom.