The Best Soil Mix for Orchid Plants (Essential Guide)

With stunning shapes and beautiful flowers, orchids make very popular houseplants that offer all sorts of uses and benefits. One of the most essential parts of keeping your orchid happy is choosing the right soil mix. Here I’m going to cover why it’s important to choose a proper soil mix as well as how to make or buy the best potting mix for your orchid.

Table of Contents:

The Best Soil Mix for Orchid Plants – The Essentials

While there are different types of orchids, the most common type is epiphytic orchids. These plants prefer a chunky potting mix with a pH of 5.5 to 6.5. To create a potting mix that provides excellent aeration and drainage, mix 1 part bark fines, 1 part perlite, and 1 part sphagnum peat moss.

How and Where Do Orchids Grow in Their Natural Habitat?

The orchid family contains a wide variety of plants and currently contains over 28,000 species. As you might expect, there are differences between species.

Orchids can be broken up into three main categories.

Epiphytes grow atop trees or shrubs.
Lithophytes grow on rocks or very rocky soil.
Terrestrial orchids grow in soil. There are over 200 terrestrial orchid species.

The vast majority of orchids are epiphytes and grow on top of tropical plants. These orchids are also the most common houseplants. However, you shouldn’t assume that all orchids grow on other plants.

The Role of Soil in Plant Health

Many plants rely on soil for several important factors.

Provides structural support by supplying a place where the plant can root.
Allows for nutrient exchange and uptake.
Allows for water retention and uptake.

As we’ve noted above, not all orchids grow in soil. However, they still need to remain upright and obtain water and nutrients.

Since epiphytes can’t obtain nutrients and water from the soil, they rely on nutrients present in the air and rainwater. They also wrap their roots around nearby materials to support themselves.

Do All Orchids Need the Same Soil/Potting Mix?

As we’ve said above, the majority of orchids are epiphytes. These orchids require a chunky potting mix that provides excellent drainage and aeration.

The following are epiphytic orchids:

Phalaenopsis orchids
Catasetum orchids
Cattleya orchids
Cycnoches orchids
Encyclia orchids

Orchids that grow on rocks will require a rocky potting mix. The two most common types of lithophytes are Phragmipedium orchids and Phragmipedium orchids.

Finally, terrestrial orchids prefer a potting mix that resembles a common houseplant mix.

The following are all types of terrestrial orchids:

Erythodes orchids
Macodes orchids
Hetaeria orchids
Zeuxine orchids
Phaius orchids
Liparis orchids

Common Signs You’re Using the Wrong Soil Mix for Orchid Plants

People often use the wrong type of soil mix for orchid plants. The most common issue is using a typical houseplant soil mix for epiphytic or lithophytic orchids.

As we described above, epiphytes and lithophytes don’t grow in the soil. Therefore, they won’t do well in a potting mix that mimics soil.

If you plant an epiphytic or lithophytic orchid in a peat-based or soil-based potting mix, you will notice issues. A typical potting mix can lead to issues with aeration and drainage.

One common sign that you’re using the wrong potting mix for your orchid is discolored leaves. Leaves often turn yellow, brown, or black when they cannot take up the nutrients they need. Waterlogged soils can also lead to issues with nutrient uptake (and may lead to common orchid plant pests, bugs, and diseases).

Another issue is root rot. As water remains in the soil, orchid roots are more susceptible to the harmful fungi that cause root rot.

If you have a terrestrial orchid and are using a soil mix labeled for orchids, you can also run into problems. Commercially available orchid potting mixes are designed with epiphytic orchids in mind.

You might notice that your terrestrial orchid looks stunted, which you can attribute to a lack of water or nutrition and even inappropriate temperature and humidity ranges. For more, see our guide to the best locations to position orchid plants in the home.

Another sign is yellowing leaves. Many orchids are also heavy feeders so be sure to fertilize regularly during the active growing season.

What Soil pH Levels Are Best for Orchid Plants?

Most orchids prefer a slightly acidic potting mix.

Since a neutral pH is 7.0, orchids prefer a soil mix with a pH between 5.5 and 6.5.

How Your Potting Container Affects Soil Choice

First off, most orchids prefer to be a bit rootbound. This means you should choose a pot that is on the smaller side.

You also want to make sure your planter has adequate drainage holes. Even if you have a well-draining potting mix, water will not be able to escape without drainage holes. (For more, see our essential guide to watering orchid plants).

The type of pot you choose does not impact the appropriate soil.

If you notice roots growing out of your pot, this doesn’t mean your pot is too small nor that you’re using the wrong soil. These are aerial roots, and they’re completely natural.

The Best Potting Soil for Repotting Orchid Plants

When it’s time to repot an orchid, you want to use a soil mix that is identical to that which you use to initially plant the orchid.

Remember to match the soil to the type of orchid. We’ll cover the proper type of soil for orchids below.

The Ultimate Orchid Plant Potting Mix Recipe

The first step to knowing the best potting mix is knowing what type of orchid you have! While the majority of household orchids are epiphytes, there are outliers.

If you have an epiphytic orchid, you’ll want to create a potting mix that mimics the orchid’s natural environment. This means a mix that provides plenty of aeration and drainage.

If you’d like to make an epiphytic orchid soil mix at home, combine the following:

5 parts pine/fir bark fines
1 part perlite
1 part sphagnum peat moss

The bark and perlite will provide drainage and aeration while mimicking the plant’s natural environment. The peat moss will help with water and nutrient retention.

If you want to buy an orchid potting mix, you have lots of options. Here are some of the best orchid potting mixes:

While the above products are great for epiphytic orchids, they aren’t the best choice for terrestrial orchids or lithophytic orchids.

For lithophytic orchids, you can use 3 parts orchid mix combined with 1 part pebbles. This will provide excess drainage and aeration.

For terrestrial orchids, you can use any soil mix labeled for houseplants. Peat moss or coco coir based mixes are great choices.

Orchid Plant Soil FAQ:

What Soil pH is Best for Orchid Plants?

Most orchid plants prefer a chunky potting mix with a pH of 5.5 to 6.5.

What are the main soil considerations when repotting an orchid plant?

When it’s time to repot an orchid, you want to use a soil mix that is identical to that which you use to initially plant the orchid.

How do you mix Orchid soil?

To make the orchid soil mix, add all the ingredients to a large container then add water until just moist. Thoroughly mix the ingredients together and then fill your orchid potting vessels.

Do orchid plants like moist soil?

Most orchids prefer a minimum amount of moisture present in the soil base at all times without overwatering the plant. Orchid plants do best in well-draining soil bases. Ensure your potting vessel has a drainage system so excess water can disperse during watering cycles.

Wrapping Up

Now that you know more about the potting mix for orchids, you can choose the best mix for your plant. Remember that the best type of soil depends on the type of orchid you have. What’s more, with a little care, orchids can live for many years to come and will happily rebloom throughout the growing season.

If you have a common epiphytic orchid, choose a chunky mix that provides excellent aeration and drainage.

For more, see our essential guide to caring for orchids whilst you’re away or on vacation and everything you need to know about orchid plant care after they finish blooming and how to manage orchids dropping leaves.

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