Make Potting Soil for Any Plant with These 5 Ingredients

With just five inexpensive ingredients, you can mix up the perfect potting mix for nearly any plant.

Whether it’s houseplants, succulents, aroids, starting seeds for your vegetable garden, you name it – these are all you need. Sure, you could buy all-purpose potting soil or a plant-specific blend, but I’ve got a few good reasons why making your own is the better way to go.

Read on to find out the five basic ingredients for any custom blend, how to store them, some common ratios and the benefits of skipping those convenient bags of all-purpose potting soil.

I started custom blending my own potting mixes a few years ago.

It started when I made the decision to stop using potting mixes that contained peat moss. The harvesting of peat moss decimates peat bogs that took millennia to form, displacing countless species of animals and plants. (You can read more about it here, plus some peat alternatives.)

However, once I made that decision, it was pretty tough to find potting mixes that didn’t have peat moss in them. Everything from your basic all-purpose potting soil down to a bag of African violet soil had peat in it.

I knew coconut coir was a much better alternative, so I started buying bricks of it and mixing it with other common ingredients found in potting mixes. It didn’t take long for me to realize how convenient it was to whip up a batch of potting media for whatever I needed.

Now, I always have these five ingredients on hand.

Coconut Coir

Coconut coir is a natural fiber made from the husk of coconuts and is often used as a substitute for peat moss. It’s lightweight, sustainable, and provides excellent moisture retention while also promoting good aeration.

In potting mixes, coconut coir helps create a well-draining environment that prevents the soil from becoming too soggy, maintaining a balanced level of moisture around plant roots. This makes it the perfect base for a variety of plant types, including tropical plants and succulents.

Pe rlite

Perlite is a lightweight, volcanic glass that is heated and expanded to form small white particles. (Kind of like popcorn!) Its primary purpose in potting mixes is to improve drainage and aeration.

Perlite helps prevent soil compaction, allowing air to reach plant roots, which is important for root health. It also ensures that excess water drains quickly, reducing the risk of waterlogged soil. Perlite is commonly used in mixes for plants that prefer well-draining soil, such as succulents, cacti, and orchids.

Vermiculite

Vermiculite is a natural mineral that expands when heated and forms small, lightweight, accordion-shaped particles. (They’re pretty cute.) It’s often used in potting mixes to improve moisture retention and nutrient-holding capacity.

While vermiculite retains water, it also allows for good air circulation around the roots. It is especially useful for plants that require consistent moisture levels, like African violets and other tropical plants. (Here’s my recipe for African violet potting mix.) Vermiculite also can retain and release essential nutrients, making it a good addition to a balanced potting mix for growing plants.

Worm Castings

Worm castings are the nutrient-rich, ahem, excrement of earthworms. They’re an excellent organic fertilizer, containing a wide range of essential macro and micronutrients, beneficial microbes, and enzymes that promote healthy plant growth.

When added to a potting mix, worm castings improve soil structure, enhance nutrient availability, and help foster a healthy soil ecosystem (especially in your garden) without the risk of over-fertilization.

Fir Bark

Fir bark is a popular organic material derived from the bark of fir trees, commonly used in potting mixes for orchids and other plants that require excellent drainage and aeration.

Fir bark comes in chunks and has a rough texture, which helps create air pockets in the soil and prevents compaction. This makes it an ideal component for plants that prefer a loose, well-drained mix, such as epiphytic orchids.

Storage

As I mentioned, I like to have these on hand so I can mix up soil when I need it. Most of these items come in bags that need to be kept sealed so they don’t spill or dry out. Having spilled and cleaned up my share of perlite and worm castings over the years, I finally ditched the bags.

These days, I use a few Sterilite storage totes with gaskets that keep moisture in/out, depending on what I’m storing. They stack nicely in my basement, where I do most of my indoor playing in the dirt. (I picked up this six-pack, five for ingredients and one to store my African violet mix in, as it’s the one I use the most.)

Is It Worth It?

You’re probably wondering what the point is when you can buy ready-made mixes. But if you garden long enough or have a large enough variety of plants, there are a few great advantages to doing it this way.

You can save money by mixing up your own blends. Many plant-specific potting mixes come at a premium despite having very common ingredients.
Fewer fungus gnats – I’ve noticed far fewer fungus gnats since I stopped buying soggy bags of potting mix at the store.
Save your back – this is by far my favorite benefit. Say goodbye to lugging 30lb bags of potting mix up to the cash register. Your average brick of coconut coir weighs a pound, and bags of vermiculite and perlite are as light as air. The worm castings might be a few pounds, but all in all, my back is much happier with this setup.

Some Common “Recipes” for Potting Mixes

As you become more experienced in growing different types of plants, you’ll gain an understanding of their soil needs. With that experience comes the knowledge to start blending your custom mixes to account for things like drainage, how long the mix stays moist, and weight when it’s wet.

In the meantime, until you’re more comfortable coming up with your own mixes, here are a few to get you started.

All-Purpose Potting Mix:

60% coconut coir
30% perlite
10% worm castings

Aroid Potting Mix (most tropical houseplants):

40% coconut coir
30% perlite
20% vermiculite
10% worm castings

Succulent Mix

50% perlite
30% coconut coir
15% vermiculite
5% worm castings

Orchid Potting Mix

40% orchid bark (or medium pine bark
30% coconut coir
20% perlite
10% worm castings

Including Sunday musings from our editor, Tracey, as well as “What’s Up Wednesday” our roundup of what’s in season and new article updates and alerts.