What is the best compost to use for repotting Orchids. 

Orchids are a very diverse and beautiful plant. They come in different shapes, sizes, and colors. There are over 20,000 species of orchids that have been identified as of now. In the wild, most orchids grow on tree trunks and branches as epiphytes. This means they grow over the ground level without being supported by other plants from below. Some are also found to be growing under rocks and boulders, which create interesting and unique displays for people who want to see them.

No wonder many people seek to grow these beautiful plants at home. But like all plants, there will come a time when they need repotting. So do you just provide them with basic compost or use something special? Let’s read on to learn about orchid potting mixes and find out what is the best compost to use for repotting Orchids. 

What is the difference between potting mix and compost? 

Many people use potting soil or orchid potting mixes to grow their plants. You might wonder what the difference between the two is, and which one you should use when planting your flowers or vegetables. In general, potting soil typically comes pre-packaged in a bag, while compost needs to be made from decomposing leaves and other organic matter. Composting is a natural process that can take weeks or months depending on the amount of material that is being composted.

The problem with orchids is that really neither is ideal. Recall that orchids are not growing from the ground usually. As already stated, they are for the most part air plants. So plopping them in soil is going to do them no good.

Common Potting Materials

 The key components of a good potting medium are fixation, humidity, light, temperature, air circulation, feeding. Therefore, typically, a potting mix for orchids is usually made up of a mixture of bark, peat moss, and sphagnum moss. 

So, what is orchid compost?

There are two common components in orchid potting mediums,. Well, actually there are three, but that third one plays a different role we will discuss a little later.

Firstly, there is bark, most commonly fir bark. Fir bark is an excellent potting mix and is a source of large woody particles that are beneficial for orchids due to their ability to hold water and air. Fir bark has the added benefit of being able to store up to 3 times as much water as hardwood, which is an important consideration for orchid growers in arid climates.

Sphagnum moss is a type of moss that is found in wet environments, such as bogs.  Using Sphagnum moss in orchid potting medium can provide many benefits. The organisms that typically inhabit Sphagnum moss are well-suited to the conditions found in orchid potting medium. These organisms include bacteria, yeasts, and actinomycetes, which are all important for the decomposition process that may lead to increased nutrient availability for plants. It also has a high water content and can hold up to four times its weight in water.

Do avoid Potting Mixes That Are Too Compact.

Charcoal – An Excellent Addition to Potting Mix

Charcoal is a very porous substance that will allow for moisture to permeate the potting medium. This will help the orchid have adequate water access and keep it from rotting over time. The charcoal also helps hold the soil together and acts as a buffer for acidic soils. Make sure it is horticulture charcoal however, and not from the barbeque. 

Type of orchid – Sympodial or Monopodial

In addition, before deciding on the ideal potting mix for your orchid, think about the sort of orchid you want to cultivate. Orchids may be divided into two types based on their growth habits. Monopodial orchids, such as vandas or phalaenopsis, and sympodial orchids, such as dendrobium and cattleya, are the two types.

Monopodial orchids grow as a single upright “stem” with one leaf following another on opposite sides of the center. Monopodial orchids are repotted in the center of the pot as they will grow straight up.

Common monopodial orchids are Phalaenopsis and Vanda (shown above).Orchids with this characteristic pattern of growth do not contain water reservoirs (no pseudobulbs) apart from their leaves and thick roots, thus should be watered just as the medium in which they are potted in dries out completely.

At the base of monopodial orchids are small nodes that lie dormant, often for a very long time. Occasionally, however, monopodial orchids will multiply by starting a new shoot at the base of the plant and in this way develop into sizable specimen plants. The new plant is called a “basal Keiki.”

https://myfirstorchid.com/2016/07/04/monopodial-and-sympodial-orchids/

Sympodial growth is defined as an orchid that does not grow from a single vertical stem but from a stem that is more or less horizontal. They have the appearance of looking like flower bulbs, but they are not. Their actual function is to store water. These kind of orchids can go for prolonged periods without water until the medium dries out because they store water in their pseudobulbs. The growth of new leaves is directly from these water storing pseudobulbs.

A pseudobulb refers to an individual “shoot” of a sympodial orchid which has a chunky base to hold water topped with leaves.

Sometimes the pseudobulb is small and the leaves are long (as in Cymbidiums, shown at above, 1st pic above). Sometimes the pseudobulbs are long and thick (they look like leaf canes) and the leaves are small. Bloom spikes usually come from where the outermost leaf meets the pseudobulb.

https://myfirstorchid.com/2016/07/04/monopodial-and-sympodial-orchids/

Sympodial orchids should be repotted every two years after flowering and when new growth develops in the spring through fall. 

When and How to repot Orchids

Orchids are one of the most popular of houseplants, but they need to be repotted every year or so, for them to thrive. It can be difficult to determine when it’s time to repot an orchid, but there are some warning signs that will help you figure out if your orchid needs a new pot. You may notice any of these traits displaying themselves: Leaves look unhealthy, roots seem dry and brown, buds begin to wilt, and/or the plant seems tired and weak. Orchids need lots of sunlight and well-drained soil. If you’re unsure whether or not an orchid needs a repot, ask someone who knows what they’re doing – even better, find a local expert! Click here for more information about caring for orchids. 

Additionally, you may see an increase in air roots. Whilst air roots are completely normal, this may be as further sign that the plant is struggling to thrive and needs a new home. See this article for more details on air roots, (also known as aerial roots.)

Repotting orchids in bloom, no matter how badly they appear to need it, will result in the loss of their blossoms. Wait until fresh growth arises after they’ve completed flowering.

The size of the container is crucial, since most orchids will blossom better if they are kept relatively pot-bound. Choose a container that just holds the root system and does not require the roots to be bent or wrapped to fit the plant inside. The roots will rot if the container is too large for the plant because the excess media retains too much water. 

Remember that a repotted orchid is a happy orchid. 

Why the Potting Mix is So Important

The potting mix is so important for orchids because it contains the nutrients and minerals, such as calcium and magnesium that they need to thrive. The living roots of the orchid extract these essential materials from the potting mix and then transport them to the rest of the plant, which enables it to produce more flowers. Here are some other reason it is important:

• Potting Mix Provides Adequate Air Circulation. Although the roots like a humid environment, these striking plants need the air to dry them out.
• Without air, the roots will start to decay, turning dark green then brown, later disintegrating into the potting medium.
• The source of nutrients for an orchid doesn’t come from the ground or soil, but from the wind.
• This can also happen over time, as the natural elements start to decay and mulch together with the weight of gravity pulling the top-heavy plant.
• Potting Mix will Allow Good Water Flow
• Potting Medium Enhances Fertilization

Buying compost or making your own?

Have you ever asked yourself – can I make orchid compost? Well, yes you can.

There are plenty of premixed orchid compost or mixtures on the market, from any good garden center or DIY superstore. And there is certainly no shame in using shop bought versions. But making your own will carry with it a sense of pride and achievement, especially if you are a very dedicated gardener. And at the same time you can pride yourself on making an organic orchid potting mix.

A good potting medium should include the following features:

• keep the moisture in
• drain quickly
• ensure enough circulation
• take a long time to disintegrate

balconygardenweb.com cover the topic very well with their 4 types of homebrew compost:

Bark Potting Mix

Fine Potting Mix

Sphagnum Potting Mix

Coconut Husk Chips Mix

https://balconygardenweb.com/4-diy-orchid-potting-mix-recipes/

Note that not all of these include charcoal and some are tailored for certain types of orchids. 

oakhillgardens.com provide the following tips.

Terrestrial orchids often grow in sphagnum moss in bogs. Epiphytes grow on mossy limbs. Keep in mind when choosing materials.

Terrestrial orchids usually require a denser mix, like that of sand and sphagnum moss.

Stability is another factor to consider. For example, packing peanuts provide good airflow but they may be too light if used as bottom material for heavier plants.

Botanists of the Texas A&M University recommend this Moth Orchid potting mix: 80% fir bark and 20% coarse sphagnum peat.

Horticulturists from the University of Tennessee, on the other hand, recommend THIS Moth Orchid potting mix: 3 parts fir bark, 1 part perlite and 1 part chopped sphagnum moss.

https://www.oakhillgardens.com/blog/homemade-orchid-potting-mix

Is orchid compost ericaceous

No. 

Ericaceous compost is a type of compost that is created from materials with high levels of acid, such as pine needles or leaves. The materials are often rich in tannin, which causes them to decompose at a slow rate. This helps to create an acidic environment for plant roots, enabling them to absorb nutrients easier. It is used by gardeners for improving soil quality and reducing weeds.

Is orchid compost acidic?

No. Remember that charcoal is commonly used to create a buffer against acid.

Can you reuse orchid compost?

It really depends on the age of the material and how decomposed it is. But it certainly is possible, especially the more solid types with bark. 

Can you use orchid compost for succulents?

Yes, orchid potting soil may be used for succulents. However, this only works in tropical climates. More moisture is ideal for tropical succulents. As a consequence, adding orchid bark or soil mix to your regular succulent soil mix may yield positive results.

Conclusion

This article has explored the unique nature of orchid plant compost. There is no combination that works best for every orchid variety. It’ll take some trial and error to figure out what works best for you and your plants, but that’s part of the fun.