Saturday, April 27, 2013

Repotting Stanhopea


 
             Stanhopea can be very rapid in growth and often need repotting every two years.  In fact, I have some forms that grow so quickly that they need repotting after only one year.  Seedling Stanhopea have been the slowest growers for me and may not need repotting as frequently, though large divisions can outgrow their containers rapidly.  I often use the term re-basketing to describe the repotting process for Stanhopea because mature specimens are grown in baskets.  Baskets are the most common containers because Stanhopea produce pendent inflorescences that either grow downward through the growing medium or along the top of the medium and out of the basket.  Immature Stanhopea can be grown in pots until they are mature enough to bloom.  It is much easier to care and grow immature Stanhopea in pots because they can be kept moist, thus preventing large shifts in the wet/dry cycle.  For this reason I usually do not place an immature Stanhopea into a basket until it will easily fit into a 6 inch (15 cm) one.

When to repot or rebasket
                Once Stanhopea reach a mature size they can be re-basketed every two years because they usually fill the container, or the growing medium begins to break down. However, if your intent is to grow a trophy Stanhopea in a large basket then you may be able to delay re-basketing for three or four years. For smaller Stanhopea, I usually don’t have to wait until the pseudobulbs fill the container, but rather if the new growth begins to appear at the edge of the container, then I determine that it is time to re-basket.
                There are two times of the year that are the best to repot or re-basket.  I usually like to repot in fall because the majority of the Stanhopea have bloomed and there is little chance of damaging a developing inflorescence.  Early to mid-fall seems best for this type of repotting.  The second best time I find to repot is in early spring after growth begins but before inflorescences have initiated. This also coincides with a time before major root growth, so there is little chance of damaging new roots.

Materials
The materials needed for repotting or re-basketing are rather easy to obtain.  These materials include either pots or baskets, growing media, basket lining material, cutting tools, plastic  labels and a disinfectant (Physan 20).  Growing media includes small seedling or terrestrial mix and Cattleya mix that I soak overnight in a mixture of Physan 20 and water to ensure that the media is sterile, and allow it to remain moist for potting purposes. If the potting medium is of excellent quality, then there will be few pieces of wood or poor quality bark that are included in the mix.  However, if you are unsure of the quality of the growing medium you can soak it overnight, and allow the poor quality bark to sink to the bottom of the container while retaining the good quality bark at the top.  You will want to do this before charcoal and perlite are added to the mix.  New Zealand moss is also used as growing media for seedling and small Stanhopea.  For specific growing medium details see the Stanhopea Growing Media post.  There are also some basket options listed here: Stanhopea Containers.  You will also need a label and a permanent marker to make sure that your Stanhopea remains correctly identified. Sterile razor blades or scissors and cutting tools are necessary to prevent transmission of viruses and bacterial infection from one plant to another.  It is always a good idea to sterilize your tools, pots, and potting media especially if you have invested a good deal of time and money into your orchid collection.  Make sure to sterilize your cutting tools between use on each individual plant.


Polyethylene 6 inch (15 cm) basket (left). Same basket lined with green moss and allowing a
pocket in the center where the plants roots can be placed (right).


The Process

           When it is time to repot a smaller Stanhopea this is a rather simple process.  I make sure I have a pot that is at least 1-2 inches (2.5-5.0 cm) larger in size than the pot I currently have the plant growing in.  I then have the appropriate growing medium available to fill the new pot. 

Seedlings
If the Stanhopea is a seedling and is planted in moss, the old moss should be carefully removed from the roots.  If the Stanhopea has grown through the media well it may be difficult to remove all of the moss from the roots, but try to remove as much of the old material as possible to prevent it from rotting the roots and pseudobulbs in the future.  Remove any dead roots with a sterile razor blade or cutting tool.  You can now place new moss around the root ball and fill the bottom of the new pot with approximately 1 inch (2.5 cm) of moss.  Place the root ball of the orchid in the new pot and position it so that the bottom of the pseudobulbs are at the same level as, or just below the top of the pot, and fill the remaining space in the pot with extra moss.   Make sure to water the medium so that it is able to keep the plant moist.

Stanhopea frymirei seedling needing new moss to be added to the pot. 
This is one of the difficulties of growing Stanhopea outdoors where birds
and other animals steal the moss from pots to make nesting material.

Small Stanhopea
                Repotting a small Stanhopea is similar to seedlings.  Remove the orchid from the old pot and remove as much of the old potting medium to prevent rotting of pseudobulbs and roots.  Remove any dead roots with a sterile cutting tool.  Select a pot that is at least 1.0-2.0 inches (2.5-5.0 cm) larger than the old container and fill the bottom with 1.0-2.0 inches (2.5-5.0 cm) of growing medium.  Place the root ball of the orchid in the new pot, and position it so that the bottom of the pseudobulbs are just below the top of the pot, then fill the remaining space in the pot with growing media.   Make sure to water the medium so that it is able to keep the plant moist. You will probably not need to water the orchid again for a few days after repotting.
 

Stanhopea oculata unpotted from a 4 inch (10 cm) pot (left).  Close up of roots of
S. oculata showing good root growth, and potting mix that should be removed
from roots before repotting (right).

Large Stanhopea
Re-basketing a larger Stanhopea requires additional materials and patience.  Removal of the Stanhopea from an old basket often requires cutting of the old basket material away from pseudobulbs that have grown through the basket.  If the Stanhopea is large enough for you to divide it you can split the orchid into several divisions with four to five pseudobulbs per division, making sure that this includes three or more pseudobulbs with leaves.  Once you have removed the Stanhopea from the old basket and/or divided it, remove as much of the old growing media as possible from the roots.  Use a sterilized cutting tool to remove any dead or damaged roots.  Choose a good size basket that will allow for 2 years of growth, approximately 2.0-3.0 inches (5.0-7.5 cm) larger than the division you are planting.  Line the basket with material to keep the growing medium in the basket (either coconut fiber, green moss, or paper bark, etc.).  Once the basket is lined, then place 1.0-2.0 inches (2.5-5.0 cm) of growing medium in the bottom of the basket.  Insert the root ball of the Stanhopea and fill in with growing media so that the bottom of the pseudobulbs are approximately 0.5-1.0 inches (1.2-2.5 cm) below the top of the basket. This is accomplished to allow the growing media to cover the bottom of the pseudobulbs so that most of the inflorescences will grow down into the medium.  However, some species allow the inflorescences to grow along the top of the growing medium, so this position allows inflorescences a good position near the surface as well.  Fill in the rest of the basket with the remaining growing medium, pressing gently to ensure that all large void spaces are filled with media.  I do this with my fingers instead of a potting stick because I tend to damage the roots more with the stick.  Make sure to wash your hands thoroughly between each re-basketing of plants to ensure everything is kept sterile.  Once the orchid has been repotted, water well and place in the shade for a few days to a couple of weeks.  Large Stanhopea that have recently been repotted may not need to be watered again for a few days or more if the weather is cool and moist.

Stanhopea oculata after repotting into a 6 inch (15 cm) basket (left).  The same
S. oculata approximately 1 year after repotting (right)
 

8 comments:

  1. Bien aimé cet article concernant le rempotage des stanhopea,je procède également plus ou moins de cet façon!
    Tes articles de culture sont bien intéressants!

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  2. Thank you for your comments Jean-Luc. It is good to know that another Stanhopea grower is using similar methods in reppoting these orchids. Any additional input you have would be helpful.

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  3. Great Article! With your permission, I'd love to reprint it in our St. Augustine Orchid Society newsletter, would be great for our members!

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  4. Thanks for this information. I bought a large Stanhopea at a garage sale for $3 not knowing what kind of orchid it was (and neither did the seller), so imagine my surprise when the flowers headed downwards out the side of the too-small earthenware pot.

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  5. What do I do if the Stanhopea is very small but only has a few roots? Can I also use coconut fibre for potting medium? It is making a few new leaves.

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    Replies
    1. nice question..
      yes if you have only few roots of your orchids,you can use Orchid Mixes for quick and healthy grow of your orchids.it also increase the no. of roots..
      you try it and get a batter results...

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    2. Thank you - I repotted the 4 small stanhopeas together into one big basket in a mix of fine coir and medium bark - they have all grown quite rapidly together and are looking healthy . I will basket them separately into their on baskets at their next repot-hopefully in early fall -which here in South africa will be about March 2018

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  6. wow nice pots..
    Really its a great information about an orchids re-potting,yes its really an orchids need re-potting after 1 year completion. at that time we have to take care an new orchids by giving them a suitable Orchid Pots for the quick grow.

    Wait for your next post...

    ReplyDelete