The Best Potting Medium for Cymbidium Orchids

Cymbidium orchids are among the most popular orchids grown by orchid enthusiasts. Their graceful sprays of vibrant blooms last for months, filling any space with spectacular color. However, getting cymbidiums to rebloom year after year requires providing them with proper care, especially when it comes to potting medium.

Choosing the right potting mix for cymbidium orchids is crucial for their health and flowering. The potting medium impacts drainage, aeration, and moisture retention around the roots It also affects pH balance and provides either stability or gradually breaks down over time With so many options on the market, how do you know which potting mix is best for your cymbidium orchids?

In this article, we’ll cover everything you need to know about selecting an ideal potting medium for cymbidiums. We’ll explore the key factors to consider and review some of the top recommended mixes for healthy, thriving cymbidium orchids

Key Factors for Cymbidium Orchid Potting Mixes

An ideal potting medium for cymbidium orchids should have certain qualities:

• Excellent drainage and air circulation
• Balanced moisture retention
• Slightly acidic pH around 5.5 to 6.5
• Large pieces that don’t break down too quickly
• Sterile and free of pests/diseases

As epiphytes in nature, cymbidium orchid roots thrive in an airy environment. At the same time, their roots appreciate moisture, so the potting mix should retain some water. An acidic pH helps cymbidiums access nutrients while preventing root rot. Large chunks or pieces create the air pockets cymbidiums need between their fleshy roots. Sterile media prevents introducing any pathogens into the root zone.

With these requirements in mind, let’s look at some of the best potting media options for cymbidium orchids.

Bark-Based Orchid Mixes

Cymbidiums do quite well in orchid potting mixes containing fir bark or other barks. The coarse, chunky texture creates excellent drainage and air circulation. Bark also gradually breaks down over a year or two, providing some nutrition before needing to be replaced.

Orchid barks usually have varying particle sizes from fine particles to large chunks. For cymbidiums, it is ideal to use mixes with predominantly large pieces of bark. Small particles can compress over time and retain too much moisture against the roots.

Some popular bark options include:

• Fir bark – The most widely available orchid potting bark, fir bark provides excellent drainage. It does tend to be acidic with a short lifespan.
• Monterey Pine bark – Known for its long fibrous strands, Monterey Pine bark has a longer lifespan than fir before breaking down. It resists compaction well.
• Redwood bark – Similar to fir bark but more neutral pH. Redwood holds its structure longer than fir before decomposing.
• Coconut husk – Made from the outer husk of coconuts, coconut husk chunks help aerate the roots. Often blended with barks.

When using bark-based mixes, it is a good idea to add sphagnum moss, perlite, charcoal, or peat moss to help retain moisture between waterings. Otherwise, the bark can dry out too quickly on its own.

Sphagnum Moss Potting Mixes

Sphagnum moss is a classic potting medium for orchids because it holds moisture well while allowing air circulation to the roots. It has antiseptic properties to protect against rot and disease. Orchid growers often use sphagnum moss blends for seedlings, rooting cuttings, or planting bare-root orchids.

For mature cymbidium orchids, sphagnum moss alone may hold too much moisture against the roots. However, incorporating 10-30% sphagnum moss into a bark-based mix creates an excellent, moisture-retentive potting medium. The bark chunks provide plenty of aeration while the moss stores water.

There are a few grades of sphagnum moss suitable for orchids:

• Chilean sphagnum moss – Affordable and readily available. It has good moisture retention properties but lower quality than New Zealand moss.
• New Zealand AAA sphagnum moss – Considered the gold standard, this premium long-fibered moss has excellent moisture holding capacity and lasts 1-2 years before breaking down.

Inorganic Potting Materials

Inorganic materials like perlite, lava rock, LECA clay pebbles, gravel, or expanded clay provide open, moisture-retentive potting media. They create lots of air pockets around orchid roots and do not break down over time. Some orchid growers use completely inorganic mixes, but these dry out quickly and require more frequent watering.

For cymbidiums, inorganic materials are best combined with bark or moss to create an airy yet moisture-retentive blend. Perlite and sponge rock are commonly used:

• Perlite – Granules of volcanic glass that are super lightweight. Perlite aerates potting mix and retains some water.
• Sponge rock – Porous, lava-like rock formed into pebbles. Sponge rock balances air and moisture well in orchid mix.

Expanded clay pellets (hydroton) can also be combined with chunky bark or placed in the bottom of pots to enhance drainage for cymbidiums.

Coconut Coir Potting Mixes

Coconut coir, also known as coconut husk chips, is a popular component of orchid mixes. Made from the fibrous pulp of coconut shells, coconut coir absorbs and holds moisture well. It provides good aeration around roots and lasts 1-2 years before decomposing.

On its own, coconut coir tends to compact over time. Mixing it with bark chunks prevents compaction and creates an excellent cymbidium orchid potting medium. The combination balances moisture retention, drainage, and air circulation.

Specialty Cymbidium Orchid Mixes

For convenience, you can purchase specialty cymbidium orchid mixes blended with the right components for optimal drainage, moisture, and aeration. These commercial mixes are sterile and ready to use right out of the bag. They take the guesswork out of choosing the right media combination.

Some top-rated cymbidium mixes include:

• rePotme Cymbidium Imperial Orchid Mix – Contains Monterey pine bark, coconut coir, turface, and sponge rock. Opens, free-draining mix suitable for cymbidiums.
• Waldor Orchids Cymbidium Orchid Mix – Blended from fir bark, chunky peat moss, and sponge rock. Designed specifically for cymbidium orchids.
• Repotme Vanda Basket Mix – Coconut chips in a fast-draining blend ideal for vanda and cymbidium orchids.

These commercial cymbidium potting mixes provide excellent drainage, moisture retention, and aeration right out of the bag. They simplify repotting cymbidiums while giving them a specialized medium to thrive in.

Potting Mixes to Avoid for Cymbidiums

Some potting mixes are actually detrimental to cymbidium orchid roots. Avoid using:

• Dense garden soil – Holds too much water against cymbidium roots leading to rot. Does not drain well.
• Peat-based mixes – Contain little or no aeration and drain poorly. Can suffocate cymbidium roots.
• Packaged potting soil – Often contains wetting agents, fertilizer, and dense fillers unsuitable for orchid roots.
• Pure moss – Sphagnum or sheet moss alone will hold too much moisture for cymbidiums. Better mixed with bark.
• Sand or gravel – Too gritty and provides no moisture retention for orchid roots.

Always check labels before purchasing potting mixes. Avoid any labeled as potting soil, garden soil, cactus/succulent mix, or other non-orchid blends. Stick with a chunky, orchid bark-based medium for best cymbidium culture.

How to Repot Cymbidiums

To repot cymbidium orchids into fresh medium:

• Choose a potting mix with excellent drainage and aeration. Go for a cymbidium blend or combine fir bark and perlite.

• Select a clean orchid pot 1-2 inches larger than the current pot with plenty of drainage holes. Plastic pots are preferable to terra cotta.

• Water the plant a day before repotting. This makes removal from the old pot easier.

• Carefully remove the cymbidium from its pot. Trim off any rotted roots with sterile scissors or pruners.

• Place a layer of medium in the bottom of the new pot for drainage. Position the cymbidium in the pot so the newest roots are just below the rim.

• Begin filling around the roots with your fresh orchid potting mix, firming the medium gently with your fingers. Do not pack it too densely. Leave a 1/2 inch space below the pot rim.

• Once repotted, water thoroughly to moisten the roots and new medium. Let excess water drain out.

• Resume normal care, allowing the potting mix to dry out moderately between waterings. Repot annually or when mix breaks down.

Choosing a specialized cymbidium orchid potting blend simplifies repotting. Fresh medium encourages new root growth and provides the balance of drainage, aeration, and moisture retention cymbidium orchids need to thrive. With a well-aerated potting mix, your cymbidiums will grow vigorously and produce their best blooms.

Frequently Asked Questions

What are the best potting mixes for cymbidium orchids?

Specialized cymbidium orchid mixes provide ideal drainage, moisture, and aeration. Bark-based blends with fir bark, Monterey pine, coconut husks, or redwood are excellent choices. Incorporating some sphagnum moss or perlite creates a moisture-retentive medium. Readymade cymbidium mixes combine these materials.

How often should I repot my cymbidium orchids?

Repot cymbidiums annually or every two years. Potting mix breaks down over time and becomes too dense. Replacing older medium with fresh potting mix revitalizes the roots and encourages new growth.

What size pot do I need for a cymbidium orchid?

Choose a pot 1-2 inches larger in diameter than the current pot. Cymbidiums have vigorous root systems and prefer being slightly root-bound. Too large of a pot can hold excess moisture and lead to rot. Look for squat pots around 4-6 inches deep.

Can I make my own cymbidium potting mix?

You can create a homemade cymbidium mix by combining 3 parts fir bark, 1 part perlite or lava rock, and 1 part sphagnum moss or coconut coir. Mixing your own blend allows you to customize ingredients, but commercial mixes provide a convenient, readymade option.

How to I make cymbidium potting mix retain moisture better?

Add more sphagnum moss, coconut coir, or peat moss to increase moisture retention. Using a plastic orchid pot rather than terra cotta also preserves moisture levels better. A humidity tray can help counteract excessively fast drying in bark-based mixes.

What should I avoid using as cymbidium orchid potting mix?

Avoid regular potting soil, garden soil, dense peat mixes, pure sand/gravel, and succulent/cactus blends. Anything labeled “moisture control” or containing water-absorbing polymers should also be avoided, as cymbidiums need excellent drainage.

A well-balanced cymbidium orchid potting medium is vital for proper airflow, drainage, and healthy roots. By providing cymbidiums with a specialized orchid bark blend, sphagnum moss mix, or commercial cymbidium potting mix, you set your plants up for success. With the right repotting practices and potting media, your cymbidium orchids will thrive for years to come.