Repotting the orchid makes a significant contribution to healthy growth. Here it has a different requirement than many other plants. The orchid guide describes in detail when the right time is, which substrate should be used and how to repot.
repot
Unlike most other plants, orchids do not tolerate repotting well, which is why they should be repotted much less frequently. A need due to lack of space does not arise so quickly, so that there is no need for an annual repot here either. Nevertheless, a new substrate is needed from time to time. Below you will find out how to do this correctly and when it is the right time.
need
There are many reasons for repotting many other plants, but usually root growth means that pots become too small after a year or two and the roots can no longer spread. This is different with the orchid, because its roots intertwine, like to hold on to the edges of the pot and are also allowed to grow out of the bottom of the pot or the substrate. That is why the Orchidaceae also gets along well with small pots, so that there is rarely a need to repot.
substrate
However, the best substrate will eventually rot. It becomes increasingly dense, squeezing the roots in this way. This prevents them from growing. In addition, the water permeability decreases, the roots intertwine too much and the salt content in the substrate can increase due to the irrigation water, the older the substrate gets. This can lead to life-threatening damage to the sensitive plant.
It should always be noted that repotting is a burden for orchid plants, it weakens them initially and therefore repotting should only take place every few years. Exceptions are situations in which pests, diseases or moldy, overgrown substrate requires repotting because the roots could be exposed to health risks.
Which substrate?
There are countless substrates to choose from for orchids, which are precisely tailored to their requirements. There are still differences in quality, which is why you should always opt for higher-quality products. These are usually a bit more expensive, but in the long run your orchid will thank you for this investment with good health and vigorous growth. In general, a good substrate should meet the following requirements.
- loose and water permeable
- low in lime
- enriched with nutrients and minerals
- pH between 5.5 and 6.0
- often provided with additives that serve to store water and/or soil permeability
substrate types
Below you will find an overview of possible orchid substrates or ingredients and what they do.
expanded clay
- well suited - high water retention
- large-scale water evaporation on the surface
wood fibers
- suitable as an additive - saves water
- optimizes soil aeration
garden soil
- only suitable for some soil specimens, such as Bletilla
grow cube
- recommended - slow decay
- light weight
- consists of water-binding fibers
charcoal
- suitable as an additive - has a disinfecting effect on bacterial infestation
- binding of toxins
- has a relaxing effect
lime
- especially important for the Paphiopedilum genus
compost
- as an additive in a solid consistency only suitable for terrestrial orchids - is very rich in nutrients
coir fibers
- suitable as an additive - especially protects young roots
- provides improved lighting conditions
cork/-grit
- mostly included in epiphytic substrates to increase air permeability
lavalite
- optimally suited for lithophytic orchids, such as Steinlaelia, because it is water-repellent
Clay
- highly recommended for pot orchids as it stores enormous amounts of water
perlite
- very well suited, especially for young plants - increases air permeability
- lets the substrate sit loosely
bark
- as an additive in mostly epiphytic standard substrates - the more delicate the roots, the smaller the pieces should be
sand
- less suitable as it allows substrates to dry out more quickly
- only suitable for overwatering
foam
- especially suitable as an additive for older orchids - increases air permeability
Seramis
- suitable as an additive for old and sole substrate for young plants
- high water retention with slow release
sphagnum
- less suitable as it decomposes quickly and usually requires annual repotting
styrofoam balls
- Conditionally suitable in the substrate - water and nutrient repellent
- increases air permeability
- lowers pH
white peat
- not suitable - absorbs a lot of water
- but compacts quickly and reduces light transmission
styrofoam chips
- well suited as drainage - has a water-repellent effect
zeolite
- suitable for preventing too much fertilizer application, as it stores it and releases it again slowly
time
For the orchid, there is a period of between two and four years for regular repotting so that it can develop optimally and remain healthy. When it comes to the optimal time, it should be noted that the plant has new shoots and these should have reached about a third of their adult size before repotting. Most orchids sprout in spring, which is why this is the best time to repot.
Some orchid species form new shoots in autumn, so that they can also be transplanted into fresh substrate here. However, the months from October to the end of January are less suitable. As a rule, the light conditions during this period are significantly lower than those prevailing from February to September. Due to the lack of light, the plant loses energy and strength, which exposes it to even greater stress when repotting.
preparation
Before repotting, it makes sense to make some preparations. Since repotting is exhausting for the Orchidaceae and they should not be supplied with additional nutrients immediately afterwards, it is advisable to fertilize beforehand with good watering. To do this, immerse your plant in a water bath a day or two before repotting and add some orchid fertilizer. Watering also has the advantage that you can then remove the plant more easily from the culture pot.
In addition, you should have some utensils ready before you start repotting:
- sharp cutting tool
- 70 or 80 percent alcohol to disinfect the cutting tool
- slightly larger culture pot and, if necessary, a special orchid pot
- spray bottle
- orchid substrate
- expanded clay
- Charcoal or sulfur powder for sealing interfaces
Implement
stuffing
The special trick here is not to damage the roots. If the aerial roots on the outside are too intertwined, they should be carefully pulled apart. Due to the previous watering, the culture pot should be easy to remove after you have pressed in the side walls a little all around. This loosens roots from the pot wall and loosens the soil.
If the plant is not easy to remove, do not use excessive force as the chance of damaging the roots is too high. Simply cut open the culture pot with scissors, if possible without cutting into roots.
earth removal
Old substrate likes to get stuck to the roots and will stick the more tightly the roots are intertwined. In order to completely remove the old substrate from the plant, it is usually sufficient to knock out the root ball on a hard surface. Be careful not to damage roots. Experience shows that knocking out works better if you proceed in stages.
That is, tap out the lower root area first while holding the remaining roots. Then release the middle root area from your hand, tap again and repeat this up to the top root area. If substrate is completely bracketed by roots, leave it there as a solution can do more damage than leaving the old soil in place.
TIP: You can also remove stubborn soil by holding the roots under a jet of water for a few seconds so that the water pressure and moisture loosen them. Use lukewarm water.
root treatment
Now is the perfect moment to examine the roots for any pests or diseases such as rot. Even if you do not discover any pests, it is advisable to place the Orchidaceae in a lukewarm water bath for two to three hours. This will smother most of the pest species that you may have overlooked.
In addition, you should observe the following steps:
- cut off rotten or dead roots with sharp scissors or a knife
- never cut through healthy roots as growth could be severely restricted
- If there are four or more bulbs, the oldest can be separated for more vigorous growth of new shoots
- Always dust interfaces with sulfur or charcoal powder to minimize the risk of infection
- If possible, do not accidentally cut/injure healthy root tissue
pot choice
In principle, it is advisable to choose a new culture pot that is no more than five centimeters larger than the previous one. Although many orchid species do not necessarily need more space every few years and do well in tight spaces, a larger pot encourages the growth of new shoots for all species.
The pot should be plastic and transparent so that the daylight that the roots need can shine through. If you use the old pot again, disinfection has to take place. Rinse with alcohol or clean thoroughly with a clean rag previously dipped in alcohol, then allow the pot to air dry. Conventional beverage alcohol is not suitable for disinfecting.
expanded clay drainage
Before the culture pot is filled with substrate or the plant is used, the soil should be covered with expanded clay. A thickness of one centimeter is usually sufficient here. The expanded clay takes on the function of drainage at the bottom of the pot and helps to prevent waterlogging.
plant placement
Once the expanded clay drainage has been laid, the plants are planted. There is a trick to ensure that the roots do not become wedged or kinked: turn the orchid slightly! The orientation must be such that new shoots have sufficient distance to the edge of the pot and can develop optimally.
substrate replenishment
Once the Orchidaceae are in the culture pot, the orchid substrate is added. This is done in portions after it has been moistened well with a spray bottle filled with water. The padding is done as described in the following steps.
- before each new portion, gently tap the bottom of the pot on a hard surface to set the soil
- when the pot is three-quarters full, the plant orientation is checked/improved again
- Substrate may only be filled so high that it touches the new shoots at most - otherwise there is a risk of rotting
- lightly press down the substrate around the main stem for more plant support
- Loosely fill up the depression that results from this with substrate.
Alternatively, expanded clay can also be used. This is also moistened beforehand and the pot is regularly tapped on a hard surface, because expanded clay also has to settle. A plastic stick can also be used to stabilize the plant.
pour
The orchid is only watered after about five days after repotting. The purpose of this is that any damaged roots can recover and interfaces do not start to rot from the additional moisture. However, since it still needs moisture, it is sprayed daily with low-lime water after repotting. Orchid plants have receptive leaves so that they cannot dry out during the watering break.
Fertilize
Both new, fresh substrate and expanded clay usually already contain nutrients and minerals. Additional fertilizing could cause an overdose, which harms the orchids. For this reason, the plant should not be fertilized in the first three to four weeks after repotting.