The Best Potting Medium for Growing Healthy Cymbidium Orchids

Cymbidium orchids, which are also called “boat orchids,” are very popular because they have beautiful sprays of flowers that last a long time. If you take good care of these beautiful orchids, they will bloom again and again, filling any room with beautiful color. One important thing to remember about cymbidiums is that they need the right potting medium to do well. The potting mix changes the pH, drainage, air flow, and how much water the roots hold on to. How do you choose the best potting medium for cymbidium orchids when there are so many to choose from?

In this article we’ll cover everything you need to know about selecting the ideal potting mix for vibrant blooming cymbidium orchids. We’ll explore the key factors to look for and review recommended formulations and ingredients. Read on for tips to help your cymbidiums flourish.

Key Factors for Cymbidium Orchid Potting Mixes

The perfect potting medium for cymbidiums should have these important characteristics

• Excellent drainage and air circulation around roots
• Balanced moisture retention abilities
• Slightly acidic pH around 5.5 to 6.5
• Large pieces that resist breakdown over time
• Sterile and pest/disease free

As epiphytes in the wild, cymbidium orchid roots like a room with lots of air flow. Plus, they need enough water in the mix at the same time. An acidic pH helps cymbidiums take in nutrients and keeps them from going bad. Large pieces make the air pockets that are needed between the fleshy cymbidium roots. A sterile medium stops pathogens from infecting the roots.

With these needs in mind, let’s look at some of the best potting media for cymbidium orchids that are healthy and blooming.

Bark-Based Orchid Mixes

Cymbidiums thrive in orchid potting mixes containing fir bark, pine bark, or other barks. The coarse, chunky texture allows for excellent drainage and airflow. As the bark slowly breaks down over one to two years, it provides some nutrition before needing replacement.

The pieces in orchid bark are usually different sizes, ranging from small flakes to big chunks. For cymbidiums, mixes with mostly big bark pieces are ideal. Over time, small particles can get squashed together and hold too much water against the roots.

Some excellent bark choices include:

• Fir bark – The most widely available orchid potting bark. It provides great drainage but tends to be acidic and breaks down faster.
• Monterey Pine bark – Known for long fibrous strands, Monterey Pine bark lasts longer before decomposing. It resists compaction well.
• Redwood bark – Similar to fir but more neutral pH. Redwood holds its structure longer than fir before breaking down.

It’s helpful to blend barks with sphagnum moss, perlite, charcoal or peat moss to balance moisture retention. Otherwise, straight bark can dry out too rapidly.

Coconut Husks/Fibers

An even better alternative to plain bark is coconut husk chips. Made from the outer coconut husk, these fibrous chunks help aerate roots while absorbing and releasing moisture slowly. Coconut husks break down more evenly than bark over time.

Compared to bark, coconut husks degrade slower and more evenly in the mix. This prevents roots from dying off as some parts of the medium decompose faster than others. The coconut chips also retain moisture better than bark, which is ideal for drier climates.

Sphagnum Moss Blends

Sphagnum moss naturally retains moisture well while allowing air flow to orchid roots. Its antiseptic properties also guard against rot and disease. Orchid growers often use sphagnum mixes when potting up seedlings or bare root divisions.

For large cymbidiums, straight sphagnum moss may hold excessive moisture against the roots. However, mixing 10-30% sphagnum into a bark-based medium creates an excellent balance of moisture and drainage. The bark provides aeration while the moss stores water.

Specialty Cymbidium Mixes

For simplicity, you can purchase specialty cymbidium orchid potting mixes blended with ideal components for drainage, aeration, and moisture retention. These commercial blends come pre-mixed and sterile, taking the guesswork out of choosing ingredients.

Some excellent readymade cymbidium mixes include:

• rePotme Cymbidium Imperial Orchid Mix
• Waldor Orchids Cymbidium Orchid Mix
• rePotme Vanda Basket Mix

These tailored blends provide great drainage, moisture retention, and aeration right out of the bag. They make repotting cymbidiums a breeze while giving the roots an optimal growing medium.

Inorganic Mix Components

Inorganic materials like perlite, lava rock, LECA, or gravel provide very moisture-retentive, well-aerated potting media. They do not break down over time. In pure inorganic mixes, more frequent watering is needed.

For cymbidiums, adding 10-30% inorganic materials into bark or moss creates an excellent blend. Perlite and sponge rock (lava rock) are commonly used. Expanded clay pellets can also enhance drainage at the bottom of pots.

Acidic, Nutrient-Rich Additives

Though not a potting material itself, cymbidiums need slightly acidic, nutrient-rich additives mixed into the top layers of the medium. Dolomite lime, crushed oyster shell, and organic compost help provide the magnesium, calcium, and micronutrients these orchids need.

Avoid Dense, Water-Retentive Mixes

Some potting media can be detrimental to cymbidium roots. Avoid using straight dense potting soil, packed peat mixes, moisture-control mixes, or succulent & cactus blends. Anything labeled potting “soil” is unsuitable and will suffocate cymbidium roots.

Now that you know what to look for in cymbidium potting media, let’s go over some tips for repotting.

How to Repot Cymbidiums into Fresh Mix

Follow these steps to refresh your cymbidium orchid’s potting mix:

• Select an orchid potting blend with excellent drainage and aeration. Go for a cymbidium-specific mix.

• Choose a clean orchid pot 1-2 inches larger than the current one with ample drainage holes. Plastic pots work better than terra cotta.

• Water the plant thoroughly a day before repotting to make removal easier.

• Carefully remove the cymbidium from its old pot. Trim off any dead or rotten roots with sterile pruners.

• Place a layer of potting mix in the new container for drainage. Position the orchid so the newest roots are just below the rim.

• Begin backfilling around the roots with fresh, orchid potting mix, gently firming the medium with your fingers as you go. Leave a 1⁄2 inch gap below the rim.

• Water well after repotting to moisten roots and settle the mix. Let excess drain fully.

• Resume normal care, allowing the medium to dry moderately between waterings.

Refreshing the potting mix annually rejuvenates cymbidium roots and encourages new growth and blooms. With a properly aerated medium that holds some moisture, your cymbidium orchids will flourish.

Provide the Right Potting Mix for Your Cymbidiums

While there’s no universally perfect potting medium for all cymbidiums, certain combinations of ingredients provide the moisture retention, drainage, and aeration these orchids need. Tailor your mix to your climate and watering habits. Aim for a chunky, orchid bark-based blend with some added moisture-retaining components like sphagnum moss or coconut coir. Refreshing the mix periodically ensures healthy, vigorous roots and spectacular blooms!