Tips & Care: Basic Tools and Equipment for Orchids (Part 2: Potting Media)

Potting Media:

Fir Bark:  

Today, sterilized fir bark is probably the most commonly used orchid potting material.  Its ease of use and comparatively low cost make it an excellent choice for growing orchids of most genera.  Sterilized fir bark comes from several species of western US trees including white fir and Douglas fir.  It is cleaned and graded before being offered for sale as a potting medium.  Fine grades are suitable for seedlings, whereas coarser grades (pieces up to 1 1/2 inches) (2-3cms) may be used for large pots.  As with other materials, fir bark may be enhanced with additives, such as perlite, charcoal, aggregates, or redwood chips.  These are often sold as proprietary bagged mixes.

Potting orchids with fir bark is easier than potting in most other media; the relatively uniform pieces readily fall into place among the orchid roots.  Because fir barck may be resistant to water at first, many growers prefer to soak it before use.  This also serves to remove some of the dust generated in shipping, which will sink to the bottom.

Bacteria that feed on the bark and bring about its eventual decay use considerable availabe nitrogen, which may leave orchids nutritionally deficient. Therefore, it is necessary to use a high nitrogen fertilizer, such as 30-10-10 for orchids grown in fir bark.

In a controlled environment, fir bark may last two years in a pot.  It has a tendency to break down much quicker in warm subtropical conditions and therefore is not used in these areas as frequently as tree fern or aggregates.

Tree Fern: 

Also known by its Hawaiian name Hapuu, it is the fibrous trunk of various species of tropical tree ferns.  It is available as logs, slabs, or other solid shapes that may be used to mount orchids directly.  It is also available in shredded form in several grades of coarseness.  Chunks of tree fern may also be found at times and they are useful for larger pots and specimen plants.  Fine tree fern may be used alone or mixed with other ingredients for compost and seedlings.

Tree fern has excellent properties as an orchid potting medium; it is easy to use and provides good drainage and aeration to roots.  However, growers with tender hands may want to use gloves when potting with tree fern, because it can be abrasive.  It provides minimal nutrition to plants and lasts about two years under normal growing conditions.

Occasionally, tree fern is mixed with additives such as redwood bark, which is thought to discourage snow mold.  Coarse aggregates can also be mixed in to "stretch" the tree fern and improve drainage.  Orchids grown in tree fern are best fertilized with a balanced fertilizer, i.e. 20-20-20.

Aggregates:

The term aggregates refers to non-organic media such as lava rock and gravel. For the sake of convenience, we include expanded mineral products such as Aliflor and Solite as well as mined products such as Australian diatomite.  Like other potting media, these materials are available graded by size, with the smaller sizes being used for specimen plants and large pots.  The larger sizes are also useful as drainage for other potting media.  

Being inorganic, these materials do not break down and are ideally suited for warm climates and outdoor growing in rainy areas.  Heavier aggregates, in concert with clay pots, can provide the firm footing needed by top-heavy orchids in windy tropical areas.  Their quick drainage also allows orchids to withstand considerable rain during wet summer months.

Aggregates are easy to use; the uniform pieces readily fall into place among the orchid roots.  Keep in mind that large pots tend to get heavy, especially if the pot is clay.  Although Solite is reported to hold up to 30% of its weight in water, these materials generally require more frequent watering than organic media.  As with other media, additives such as sphagnum may be used to modify the moisture holding properties.  Aggregates provide excellent drainage and aeration to orchid root systems and will last indefinitely. Although they can be reused, this is not advisable unless the used media can be sterilized.

Complete nutrition must be supplied when potting with aggregates;  use a balanced fertilizer such as 20-20-20. It is also recommended to thoroughly flush potted orchids with clean water monthly to avoid fertilizer salts from building up.  Many growers like to prerinse their medium prior to use to remove dust and fine debris.

Sphagnum moss:

This has become increasingly popular as an orchid potting medium in recent years, particularly with the introduction of high-quality, long fibered New Zealand sphagnum.  Comparable quality is also available from select Chilean sources.  There are different grades of sphagnum available from locations throughout the world;  choose the one that fits your budget and quality requirements.

Sphagnum is easy to pot with; however, you should presoak it overnight in a bucket of warm water.  Many growers like to add a teaspoon of an algicide such as Physan or RD-20.  Squeeze it out gently before packing it around the roots, taking care to not pack too tightly.  A rhizome clip or stake may be used to stabilize the orchid.

Sphagnum moss is difficult to rewet once it has dried out so it is best to keep the plants evenly moist but not soaking!!!  Adjust your watering schedule accordingly.  As a result, this medium is not for orchids that like to dry thoroughly between waterings.

Although it is thought that the moss supplies some minor nutrition, it is best to fertilize plants potted in sphagnum with a balanced fertilizer such as 20-20-20.  Additives such as charcoal and perlite are often used to prevent the moss from compacting and keep the mix open.  Sphagnum can last up to two years but in practice, plants are usually repotted yearly, especially phals.

The moss can harbor the fungus that causes the lymph infection Sporotrichosis.  Although cases of infection are not especially common among orchid growers, the fungus can enter the body though a cut or other opening and cause symptoms from mild to severe.  As a precaution, wear rubber gloves when working with sphagnum moss.

Osmunda:

Until the early 1950's, osmuda was the potting media used for growing orchids.  Its increasing scarcity and consequently high price has caused it to fall out of favor.  It also requires some skill to be able to successfully pot with osmunda.  Other potting materials available today are much easier to use.  There are certain instances when this medium might be just what is called for to coax a recalcitrant orchid into growth. It is also useful to put a small pad of osmunda beneath the rhizone when attaching a plant to a mount; this provides a little extra moisture while the plant gets established.

The fibrous roots of the osmunda fern provide a higher quantity of nutrients than most other potting materials, therefore they require more dilute fertilizer application.  Use one-half the strength used for other media.  Despite the fine texture of osmunda, it does not break down quickly and will generally last in excess of two years.  Additives such as charcoal can be used to maintain the openness of the mix and keep it from souring.

Potting with osmunda requires some practice; chunks are torn into appropriately sized pieces and forced into the pot and around the roots with a "potting stick" or similar tool (you can use a sushi chopstick), creating enough pressure against the roots to hold the orchid firmly firmly in place.  An orchid that has been properly potted in osmunda usually requires no clips or stakes unless it is top-heavy by nature.

Coconut husk chips (CHC):

Graded chips, or chunks of coconut husk have enjoyed some popularity as an orchid growing medium.  Indications are that it may offer better aeration and stay less wet than coconut fiber.  Some growers have had success using the fine grade on its own as a seedling medium.  It seems to provide a constant, even source of moisture without the dry to wet problems of sphagnum, yet does not stay soggy.  It is common practice with this medium to provide an overnight soaking prior to rinsing with water to leach out any accumulated salts that may be present on the coconut husk, depending on its source.  The chunks may be used on their own or mixed with charcoal, Aliflor or lava rock.

There are also many formulated potting mixes available at garden supply  stores that are suitable for growing a wide range of orchids.  We have not included those here because we do not endorse any particular proprietary potting mix and the types and availability vary regionally.

Thanks Ned Nash

Tips & Care: Basic Tools and Equipment for Orchids (Part 1: Pots)

Few expensive tools are needed for orchids, but growers will need to spend their time, (not their money) making sure they have the correct medium and container to match to the orchid.

POTS:

There are many types of pots available that are suited for the culture of orchids but the basic choice remains: clay or pastic.

Most clay orchid pots are terra-cotta and often have additional drainage either as holes or slots around the bottom edge of the pots.  There are several individuals offering clay orchid pots that are decorative as well as functional and you may find these worth investigating.

The basic characteristics of an orchid pot are that it is shallow in relation to it height and has addional holes for drainage and root aeration.  Plastic pots generally have the same features, but the plastic retains moisture longer than a porous clay pot.  Additionally, plastic pots require specific rhizome clips and stakes that don't always anchor as well as their clay counterparts.  In either case, it is important to choose the type of pot based upon your other cultural factors, such as average temperature, air movement, frequency of watering, and choice of potting medium as well as the genera being grown.

Generally, temperate growers who have greenhouses tend to prefer plastic pots and a moisture-retentive mix such as fir bark or sphagnum. Subtropical growers, whose plants are exposed to the elements, tend to use fast-draining media, such as the aggregates and clay pots.  Subtropical growers, who also often grow their plants outdoors or in areas exposed to the wind, find that clay pots give a weighted, bottom-heavy aspect that does not blow over as easily as plastic.

Both, clay and plastic pots are available in a wide range of sizes from 2 inches (5cms) up to 12inch (30cms) and larger.  Choose the appropriate size to allow for approximately two years' growth.

Drainage:

Whether or not to use additional drainage material in the bottom of orchid pots is a continuing debate.  Many growers advocate putting some sort of drainage material in the bottom, whereas others prefer to fill the whole pot with medium.  Although the choice is ultimately yours, most recommend that you use drainage.  The argument against additional drainage material is that it does not really serve any useful purpose, and that it only provides a good hiding place for pests such as slugs and snails.  If you regularly bait for these pests, this is not an issue.

The purpose of putting pieces of broken crock in the bottom of orchid pots is to prevent the medium from compacting and blocking the drainage holes.  It also serves the purpose of providing aeration to the interior of the pot where stagnant conditions easily develop.  Indeed, certain pot manufacturers have created pots with drainage built in as upside-down slotted cones.  This consideration is more critical as pot size increases and becomes imperative when growing specimen-size plants.  Without drainage, the center of the medium in a 12 inch pot can become very dank.

Any coarse, inert, inorganic material can be used as drainage. Broken clay pots (sterilized), styrofoam, and landscape lava rock are all good choices and are easily available.  Lighter materials can help reduce the weight of large specimen plants, while smooth river rock can add stability to a top-heavy phalaenopsis or dendrobium in a plastic pot.  The most important qualities are that the material is coarse enough to provide adequate air space and not break down in the pot.

To be continued...

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Special Techniques of Bonsai (Part 1): SAIKEI

Saikei (pronounced "Sigh-kay") , is a form of bonsai in which trained plant specimens are brought together in a realistic, proportionate interpretation of a landscape. Although it sounds simple, several horticultural skills are involved, all of which must work together to create a natural scene.
As far as plants are concerned, some of the smallest and youngest, bonsai material can be used in saikei. Distinctive, and with some unique properties of their own, these plants can be the small, imperfect,  material frequently rejected for traditional bonsai. They can be so small that ones reserved for mame bonsai can be used. Even seedlings, which are far from aged and branched, are appropriate.

Another distinct difference between Saikei and the more familiar forms of bonsai is that the use of a variety of plants in one setting is more the norm than the exception.  Since saikei is an attempt to translate a brad natural scene into miniature terms, the realistic use of different varieties of plants is necessary.  However, saikei is not confined to the use of multiple plants, and there are justifiably famous examples which use a single, well grown plant in the finished landscape.


The bonsai is planted in a tree stump, chosen, as in a rock planting, for its aesthetic qualities and to complement the other plants. Providing enough water is the biggest problem, but it can be partly solved by placing the planting in a pond in the garden.


It is important with saikei to use plants that require the same conditions. Without cultural similarities, the job of maintaining the health of the landscape can be an overwhelming, if not impossible, chore.
Involved in saikei too are the rocks, sand, shrubs, and accompanying plants common to both woodland and shore; in fact all the natural phenomena, streams, rivers, fallen trees, beaches, craggy outercroppings or ledges, waterfalls, ponds, marshes, and glades, can be captured in saikei.
Your task is to combine all these elements with the trees, shrubs mosses, and lichens into a harmonious whole, using material that will live together in one container.

The language used in saikei is the same as in traditional bonsai: the formal and informal, windswept and cascade styles are used; the scale and proportion of plants to each other and to the rock or rocks (it is not essential to use any rocks in a saikei composition and there well known examples in the bonsai world that do not; most, however, do feature one or more) is vital; and a harmonious overall effect is the goal.


In choosing rocks suitable for planting, look not only for distinctive, craggy rocks but also for those that have a meandering thread of white or beige coursing down their faces, to resemble a waterfall or stream.  Keep a sharp eye out for a stone that loos like a hillside undulating downward in terrace after terrace, or a craggy rock with a generous plateau that could represent the meadow below a precipice in your final picture.  Use whatever the rock can offer you as a head start toward realism.

Remember to turn your bonsai periodically so that the plant can grow evenly and have enough sunlight from every side.


Rocks for saikei plantings should be prepared in the same ways as for root over rock bonsai.  Muck and wire, moss and awl are the tools and materials you need, and trays of clay or interesting stones, cement or wood are also desirable.  Wash the soil from the roots, but take care to keep the rootball whole.  Separate the roots into quadrants to ascertain where they will naturally fall, if you are using a variety of plants, select leaves, trunks, and branch positions that are in scale and color harmony with one another.  When planting ground cover and accompanying plants, be sure that soil and rock will still be visible.
If the stone has been cast in the role of a mountain, the plants should be proportionally smaller.  If no, the plants can dominate the scene, with the rock or rocks partially hidden beneath the soil, more nearly approximating the way rocks are found in nature.


Saikei offers an opportunity to use tiny horticultural gems.  Mosses, lichens, and tiny violets kept even smaller by judicious pinching, grasses, miniature veronicas, and thymes are all possibilities, depending on the scene you are painting and the appropriateness of the plants to that scene.  Some of these can be found growing wild in cities and in the countryside, and have the advantages of being native to the area, hardy to the climate, impervious to pollution and drought, and available at the lowest possible cost.

As with other rock plantings, watering is essential.  Keep saikei in dappled shade and water two or three times a day.   Since drainage is quick and water retention capabilities are at a minimum, this is imperative.




Thanks Susan Bachenheimer