Stanhopea Pests

Stanhopea are relatively pest free orchids when compared with other genera.  The common pests are snails/slugs and spider mites.  For me the snails/slugs are a constant battle, and are the more serious pests.  These mollusks can damage new growth, inflorescences, and flowers.  They usually do not have any more of an impact on a plant other than cosmetic damage, though long term damage can occur if they continually eat new growth and prevent the plant from growing well.

Bush snails (orchid snails)
from Orchidboard.com

I use metaldehyde based snail and slug bait (e.g. That’s It) to control these pests that is a granular form, and doesn’t leave a meal residue in the pots and baskets. I also have been recently trying “Sluggo Plus” suggested by a blog visitor.  This product breaks down into iron and phosphorus which plants benefit from, and it is less environmentally damaging. "Sluggo" seems to be a good product to use and does not adversely impact children, pets, and wildlife in the amounts used as directed.

Spider mite spots on leaves of Stanhopea.
From Orchidboard.com

Spider mites on underside of plant
leaves. From Got Pests? website
at Maine.gov

 

Spider mites can be a problem for Stanhopea and are generally noticed when light yellow spots appear on the leaves in large numbers.  I have had very few problems with spider mites in my collection perhaps because I grow most of the Stanhopea outdoors where spider mites have to deal with predators.  That being said, environments that are low in humidity and dry often allow plants to harbor spider mites. The best control I have found for these is to apply a rosemary oil based mite control (e.g., SNS-217) to the leaves and pseudobulbs every few weeks.  This treatment removes the spider mites and then you can ensure that they don’t return by increasing humidity in the environment and checking your plants often to spray again when necessary.  These rosemary oil based sprays are organic and pose less of a threat to pets and wildlife.

Stanhopea Spring 2013

Spring is well under way and Stanhopea are showing signs of growth and preparations for inflorescences. While some Stanhopea have just begun new growth, others have just completed winter growth, and still others have not grown since last fall.  It has been interesting to note how varied the timing and duration of growth Stanhopea exhibit as my collection has increased.  Growth in Stanhopea can be so variable between species and even sometimes between different forms of the same species.  Some of the easiest species of Stanhopea that I find to grow (S. oculata, S. tigrina, and S. wardii) grow intermittently throughout the year, taking short breaks between growth cycles.  Other Stanhopea such as (S. anfracta, S. gibbosa, and S. panamensis) begin a growth cycle in early to mid-spring, and then again in summer before flowering.  Other Stanhopea (e.g., S. insignis, S. lietzei, and often S. shuttleworthii) don’t begin growth until summer and then only produce one cycle of growth. 



Stanhopea tigrina "Glory of Mexico" with new maturing growth from late winter (left).  Stanhopea posadae with new growth started in early spring (center). Stanhopa anfracta with new growth started in spring (right).



These differences between the growth cycles of different species may be due to cultural conditions, or the maturity of the Stanhopea plant.  The species that grow intermittently through the year may be because they are the best adapted to the growing conditions that I have, and thus grow almost continuously.  In addition, these Stanhopea that grow well may be doing so because they are some of the largest specimens that I have and happily grow throughout the year.  This latter option may not be very consistent because two of my large Stanhopea (S. ruckeri and S. shuttleworthii) only produce one growth cycle per year.  It will be interesting to see if these observations of growth cycles remain consistent or vary over time and as the plants age.  It would be appreciated if those of you who have different growing conditions than mine (e.g., greenhouse conditions or a tropical climate) could post some of your observations.  Knowing when Stanhopea start new growth cycles and when they bloom allows us to determine the best time to transplant them (either spring or fall) depending on the species.  I usually attempt to re-basket Stanhopea just before a new growth cycle begins while the plant is dormant, and either before or just after flowering for the year.

Stanhopea frymirei (left), Stanhopea impressa (center), and Stanhopea nigripes (right) with new growth starting in mid-spring.

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)

 

Stanhopea Growing Media

It has been stated by several orchid growers that Stanhopea will grow in almost anything.  This includes rock and pumice and other non-organic materials to organics. Barney Greer wrote that another grower used pure horse manure as growing media for Stanhopea.  I usually avoid using rock and pumice because this adds weight to an already heavy basket – especially for large trophy Stanhopea.  That being said I have found Stanhopea to grow best in a few types of growing media including orchid fir or redwood bark seedling mix, and medium or Cattleya mix, and New Zealand moss.

Fir and Redwood Bark Seedling Mix

I use this mix for smaller unbloomed Stanhopea or ones that will be moved into their first baskets.  I also use this mix to top off baskets that I have of mature specimens to keep the upper layer of the basket moist in my dry environment.  The seeding bark mix is a mixture of 60% 0.25 inch (0.63cm) fir or redwood bark, 25% 0..25inch (0.63 cm) pumice, and 15% activated charcoal.



Seedling Redwood Mix

 Fir and Redwood Bark Cattleya Mix

This mix is used for most of my medium to large Stanhopea that are grown in 8 inch (20 cm) and larger baskets.  This mix holds moisture but allows enough air and prevents overly moist conditions for Stanhopea that need a dry rest period during the winter months.  The Cattleya mix is a medium bark that is 60% of the mixture with 0.50 to 0.75 inch (1.3 to 1.9 cm) fir or redwood bark, 25% 0.25 inch (0.63 cm) pumice, and 15% activated charcoal.

Cattleya Redwood Mix

New Zealand Moss

I use this moss to provide consistent moisture in and around the remaining roots and base of the pseudobulb. This moss is especially useful for bare root plants that I often receive as imports or from divisions.   Most imports are  bare root, so it is important to keep the remaining roots moist to facilitate new root growth from the pseudobulbs.  I also use this moss as a first potting medium for 1-2 year old seedlings that have small fine roots and need constant moisture to remain viable in my dry environment.  This moss is a little more expensive than other types of mosses, but it is worth the extra cost for the consistency of the medium, and for the superior water retention.  If you have the extra money to purchase this moss and have difficulty in keeping your Stanhopea moist, then you can use this as the sole growing media for your orchids.

New Zealand Moss

 

 

Green Moss

I use green moss to line the baskets of most of my Stanhopea.  It has a consistent texture, and is attractive.  It is also relatively inexpensive and easy to obtain.  The moss also allows the inflorescences of Stanhopea to pass through easily and mature.  This moss holds the growing medium in place in the baskets, while also preventing dessication of the roots because it does hold moisture in after watering.  I usually place approximately 1 to 1.25 inch (2.5 to 3.2 cm) thickness of the moistened moss around the basket and make sure that it is thick enough to hold in the growing media firmly. 

Green Moss Basket Liner

 

Other Basket Liners

Several other basket liners can be used for Stanhopea.  If you have the money you can always use New Zealand Moss to line baskets and it has similar properties as green moss for this use.  Pre-manufactured coconut fiber liners are also available and are relatively inexpensive and easy to install. Just drop the coconut liner right into the basket and you are ready to start placing the media and Stanhopea in.  Remember to buy the non-plastic lined coconut fiber liners so that this will allow the inflorescences to pass through the liner easily.  Other liners that have been used include a few sheets of newspaper.  Though I have not used newspaper for this purpose, I understand that the raw look of the paper fades with time and still allows the inflorescences to pass through the paper.  I find the look of the newspaper to be a little unnatural, though it is more ecofriendly to recycle in this fashion.  Stanhopea growers in Australia have used paperbark from Eucalyptus, Melaleuca, and Tristania trees to line baskets.  If done properly and not applied too thickly, this allows the inflorescences to pass through the gaps in the bark while still holding in moisture and the growing medium.  I am currently attempting a few baskets lined with Tristania paperbark so see if it works for me as well.  The paperbark is more natural looking than newspaper and is relatively accessible from landscape trees in southern California.  I am fortunate to have a large Tristania tree in my landscape that provides rather nice quality paperbark for free.


Coco Fiber Liner



Stanhopea Spring Culture Checklist

 

Winter Wrap Up

The winter of 2013 was particularly difficult for growing Stanhopea.  In January the temperature dipped to 31°F (-0.6°C) for only the second time since I have lived in San Diego.  This low temperature duration was only for a few hours on one night, but it was unusual in that is was part of a 10 night period in which temperatures ranged from 35-39°F (1.7-3.9°C).  This long cold period was particularly difficult for several of the Stanhopea. Some orchids exhibited  bacterial growth presenting a few days after the cold snap along with a loss of  few leaves after several weeks.  In addition to this cold, a very intense hail storm occurred one night and caught me off guard.  Most of my Stanhopea collection is sheltered by trees, roof overhangs, and plastic saran; however, a few plants were partially unprotected during this storm and took some damage.  If I continue to have these tough winters, it will give me incentive to complete the building of a cool greenhouse to protect the orchid collection better by next year.


Stanhopea shuttleworthii growing underneath a tree canopy.  The plant looks good from a distance (left).  However the hail storm damaged the right side of the leaf causing pitting and the cold weather cause bacterial spotting (right)

Stanhopea Spring Culture Checklist

·         Begin watering these species regularly when new growth begins (S. hernandezii, S. insignis, S. jenischiana, S. lietzei, S. maculosa, and S.martiana).

·         Begin fertilizing all species regularly once new growth begins.  I often reduce the manufacturer’s recommendations in half and fertilize every week or what is known as weakly-weekly.  Stanhopea can be rather heavy feeders when they are in active growth.

·         Weed baskets to prevent ferns and other plants from taking up space in baskets.

·         If you grow Stanhopea in a sunny area or a greenhouse that receives strong sunlight you may want to place saran shade cloth over the growing area in early spring before the sunlight becomes too strong for them.  You may also want to consider moving the Stanhopea to another shadier growing area.

·         Use of methaldihide products is advised on a weekly basis at this time to prevent slugs from disfiguring new growth and impacting new inflorescence and bud growth.  I often use a product called “That’s It” that is a granular form and therefore leaves less residue in the growing media.  I am currently testing some more organic methods of slug control.

·         In mid to late spring make sure to check for growing inflorescences and ensure that their growth is unimpeded by other plants or the basket.  If need be place a plastic label underneath the inflorescence to help direct the growth out of the basket.

·         Spring is the second best time to re-pot or re-basket Stanhopea, I think late fall is actually the best time because most Stanhopea have already bloomed and are in a rest period.  It is recommended that you allow new growth to begin before you re-basket so that the growth can mature somewhat before you transplant the orchid.  This will prevent the new growth from being impacted during the process.  Early spring is a good time to transplant because it will also prevent damage to most nascent inflorescences.

·         Keep a careful eye out for spider mites as the spring continues and our weather begins to warm and dry out.  Small yellow spots on the foliage signal that these pests are active on your Stanhopea.  Spray infected areas with an insecticidal soap to kill the pests as soon as possible to prevent them from damaging the plant further and spreading to other orchids.

·         You should also be diligent in keeping watch for fungus infections at this time on leaves.  Several fungus attack leaves when humidity is high and temperatures are warm. Black or brown spots of leaves and yellowing of leaves in odd patterns are usually the cause of fungus or bacterial infection.  Treat with a fungicide or bactericide.  I often use Physan 20 to deal with the problems and prevent further damage to the plants.

Stanhopea Containers

Stanhopea inflorescences either grow down through the growing media, or along the top of the media and open as a pendent inflorescence.   Therefore, it is highly recommended to grow Stanhopea in a basket.  There are some individuals who have been successful in blooming Stanhopea grown in plastic pots with holes in the bottom.  However, as the plant grows larger, and the inflorescences increase in size, it becomes more difficult for the inflorescences to make their way out of the pot and the inflorescences often die.  Some fortunate individuals have been able to successfully grow and bloom Stanhopea mounted on wood, cork, or wood rafts when the growing conditions provided are moist and humid at all times.  However, here in southern California where our summers are rainless and humidity is low, baskets seem to work best for growing Stanhopea. For seedlings and small plants, I grow these in 2-4 inch (5-10 cm) plastic pots before they can be transferred to a 6 inch (15 cm) basket.

Stanhopea embreei inflorescence emerging from a plastic basket (left).  Stanhopea shuttleworthii
 inflorescences emerging from a plastic basket (right). Note that I had to remove the top rim of the
 basket to allow for the maturation of the upper inflorescences.  The Stanhopea on the right is
 definitely due for re-basketing.

 

You may be asking what kind of basket is best for growing Stanhopea?  A basket that is durable and strong is a good start, and most Stanhopea grow best in baskets that are either 6-12 inches (15-30 cm) in diameter.  Larger baskets can be used if you want to create a specimen plant.  The baskets should be approximately 5-6 inches (13-15 cm) deep to allow the inflorescences a chance to grow completely through the growing media.  In some species (e.g., S. trigrina and S. wardii) the inflorescences grow longer and these can accommodate deeper baskets up to 8-10 inches(20-25 cm) in depth.  There are a variety of baskets on the market that are sufficient for growing Stanhopea.  These include polyethylene plastic, wire or metal, and wood slat baskets.  I have also seen Stanhopea grown in ceramic baskets, netted bags, and in almost any container that has holes large enough to allow the inflorescences to mature and grow out of the basket.  I will discuss each of the three main types of baskets mentioned above and their advantages and disadvantages.

Plastic baskets are relatively inexpensive, durable, lightweight, and can be stored and transported easily.  As my Stanhopea collection has grown, I have chosen this type of basket over the others because of the cost, however these are not the most ornamental of the baskets.  These baskets can be obtained in sizes that range from 4-12 inches (10-30 cm) in diameter.  I usually choose the 6 inch (15 cm) size as the minimum due to my dry environment, because this size basket dries out much less frequently than smaller baskets.  Most of my smaller Stanhopea are placed in plastic baskets until they can be transferred to a larger wire baskets later.  The holes in the plastic baskets are approximately ½ -1 inch (1.3-2.5 cm) in diameter and are sufficient in size to allow the inflorescences to pass through. One issue with plastic baskets is that as the Stanhopea grow larger, they will often send new pseudobulb shoots through the holes in the basket.  Once this growth elongates through the holes and matures, one must cut the plant out of the container when it is time to re-basket.  This situation can often lead to a frustrating time when re-basketing and an increased chance of damaging the plant.

Plastic baskets in the 8-10 inch (20-25 cm) sizes (left). Stanhopea oculata growing in an 8 inch (20 cm) basket (center).  An example of a Stanhopea gibbosa pseudobulb that has grown through the side of the basket (right).

Wire and metal baskets are more expensive, very durable, and rather lightweight.  I choose to grow my larger Stanhopea in these baskets which can vary in size from 10-18 inches (25-45 cm) wide.  These baskets have an improved aesthetic quality and the larger spaces in between the wire allow the inflorescences to easily pass though.  I also choose this type of basket to grow the larger specimen size Stanhopea.  This is because wire baskets allow the pseudobulbs to grow around the edges and sides so that the plant can be grown in the basket for longer periods of time, usually 3-4 years before re-basketing.  The durability of these baskets is good and they can often last for a decade before being replaced.  When re-basketing it is much easier to break apart the stems around a wire basket than a plastic one.  I have several Stanhopea that I grow in 12 inch (30 cm) wire baskets that are flattened on one side to allowing them to be hung on walls and flat surfaces.  I have chosen this type of basket to facilitate the expansion of my collection and use of a preponderance of wall and flat space to exhibit the collection.  The downside to this type of basket is that Stanhopea will often grow the inflorescence toward the back of the basket and wall.  I usually turn the basket around temporarily to allow the inflorescence to grow and bloom normally.  I can usually avoid most of the backward growing inflorescences when re-basketing by ensuring that the new lead growth is pointing toward the front of the basket.

Stanhope oculata in a 12 inch (30 cm) basket that I have grown for over 12 years (left).  Newly divided Stanhopea florida in a 12 inch (30 cm) flat basket growing on lattice (right)

I think wood baskets are one of the most ornamental of the choices, but are expensive and bulky.  The baskets are often available in teak and fir with 8-12 inch (20-30 cm) size widths, and have ½ inch (1.3 cm) slatted openings on the side, and 2 inch (5 cm) openings on the bottom that allow the inflorescences to pass though.  These baskets are strong and long lasting, but are rather heavy and not easy to transport.  The thickness of the wood slats can inhibit inflorescence growth, so an attentive eye is necessary to ensure that the inflorescences are allowed to grow between the slats.  I have several Stanhopea that are growing in visually important areas in my yard where I grow them in wood baskets for high impact and ornamental character.

Coryhopea hybrid growing in a 12 inch (30 cm) fir basket on my patio (right).  Stanhopea candida growing in a 10 inch
(25 cm) fir basket that is kept warm by growing in my bathroom over winter (right).

 

Stanhopea Water Requirements

Many Stanhopea require copious amounts of water during the summer months here in southern California.  I usually water three times a week from spring to fall and once a week or not at all during the winter depending on the amount of rain received.   I water more frequently during the summer and early fall when hot weather is expected (above 85°F or 29.4°C). I water and mist the plants every day if temperatures are very extreme (above 95°F or 35°C).  Several Stanhopea prefer lower amounts of water during the winter and often require this to induce bloom the following spring and summer.  The Stanhopea that benefit from this reduced watering treatment include (S. hernandezii, S. insignis, S. jenischiana, S. lietzei, S. maculosa, and S. martiana).

 I usually begin to reduce the water for the above mentioned species in December and continue until new growth begins (usually April).  I reduce watering by approximately 30-40 percent of what the other species are receiving.  This usually means that each week I skip one watering application for the above mentioned species to allow them to dry out a little more than the others.  This doesn’t mean that I allow the growing medium dry out completely.  Most Stanhopea cannot tolerate the medium drying out for extended periods of time.  An overly dry growing medium could also damage mature leaves, new growth, and roots of Stanhopea.  Therefore, you only need to allow the medium for these species to dry out slightly but not completely.

Stanhopea insignis with a low pressure stream
bubbler used to water during the dry season.

Water quality is a concern of mine and I choose to grow certain species of orchids for that reason.  I have tested my water that is delivered by the city of San Diego water department and found the pH to be high – 8.2, with total dissolved solids at 337 parts per million (ppm), and sodium levels at 74.2 (ppm).   This means is that the pH of the water and dissolved solids is high enough so that it is not conducive to grow several species of orchids that require neutral pH and lower dissolved solids. High levels of dissolved solids usually leads to stunted plant growth, and build up of salts in leaf tips.  You should also fertilize more frequently but with reduced concentrations of fertilizers when using water with high dissolved solids.

I was faced with two choices for growing a large collection of orchids, either grow orchids that would tolerate these water conditions, or buy an expensive reverse osmosis system and pump to supply treated water to the orchids.  I chose to grow orchids that would tolerate the water quality from my city water supply.  I selected Stanhopea because they had proved in the past to be relatively tolerant of poor water quality and could be easily grown outdoors.  The list of orchids that would grow under these conditions was long enough to make the decision difficult.  These other orchid genera include Encyclia, Cattleya, Cymbidium, Sobralia, and Zygopetalum.  Many of these genera require more sun and a good portion of my growing area is shaded throughout the year.  Several of the above mentioned genera  grow very large and would take up even more space than Stanhopea.  Therefore my choices were reduced enough to settle on growing Stanhopea.

My plan is to eventually obtain a reverse osmosis system for my orchids over the next few years, but until that time Stanhopea grow rather well without it.  The reverse osmosis system would allow me to grow much healthier and well grown plants in the future.  I currently have 53 Stanhopea in my collection and the collection keeps growing every year.  This size of an orchid collection makes it difficult to use another source of pure water (rain water) to irrigate the orchids, but I do collect enough rainwater in the winter to flush the baskets at that time and remove built up dissolved solids in the growing medium and sphagnum moss that I use to line the baskets.  The size of my collection and my work schedule also preclude me from hand watering the collection.  For now I am using the municipal water system and the Stanhopea tolerate the water quality quite well. The orchids tolerate this poor water quality because I soak the basket and growing medium once a week, thus leaching the dissolved solids out of the media to prevent build up.  There is some accumulation of salts in the oldest leaves of some Stanhopea species that cause unsightly brown leaf tips on a few leaves.  This usually occurs more frequently just prior to the leaf excising and falling off, so it is not a long term unsightly issue.