If you’re a plant life aficionado, you probably have all sorts of houseplants around your home. This may have got you wondering about the best soil for indoor plants.
The ideal option for indoor plants is a potting mix. This is a plant growth medium that contains no dirt. Its main components are typically perlite, coco coir, peat moss, vermiculite, and worm castings.
Read on to find out more about why a potting mix is the best soil option for your indoor plants. We’ve also included detailed instructions on how to make a potting mix yourself.
What Types of Soil Are There for Indoor Plants?
There are two main types of soil that you can use for your indoor plants. These two types are soil mix and potting mix.
Soil Mix
Soil mix is composed of a variety of organic materials. These materials include peat moss and perlite. Another key component of soil mix is compost, which is typically made from cow manure.
The main distinguishing feature between soil and potting mix is that the former contains dirt, while the latter doesn’t.
For outdoor plants, the presence of dirt is unavoidable. This makes soil mix the better option for such plants. In the case of indoor plants, you’re better off going for a potting mix to avoid the harmful pathogens that dirt may contain.
Potting Mix
Potting mix is the medium of choice for most people when growing plants indoors. This is because a potting mix is sterile and completely free of dirt.
So, what exactly is a potting mix? It’s an assortment of organic materials such as perlite, coco coir, vermiculite, and peat moss. Each of these components plays a role in the potting mix’s ability to provide the aeration and drainage that your plants need to thrive.
Fertilizer
The main downside of potting mixes is that they usually don’t contain a lot of nutrients without fertilizers. Therefore, you’ll need to add fertilizer to allow your plants to get the nourishment they require for healthy growth.
If your priority is convenience, then your best fertilizer option is slow-release pellets. These pellets gradually release the nutrients they contain into the potting mix over three months. All you have to do is throw them into the potting mix when planting.
Another option is commercial fertilizers that are designed for indoor plants. Choose one with the desired concentration and apply it to your potting mix by following the instructions on the package.
Dirt
As we’ve mentioned before, dirt is the main factor distinguishing between soil mix and potting mix. It’s a necessary evil when planting outdoors.
However, you should avoid including dirt in the medium in which you’re growing plants indoors.
Why Use a Potting Mix?
We’ve already established that potting mix is the best option when growing indoor plants. Why is that the case?
The first advantage of potting mixes is the absence of dirt in them. This means that you don’t have to worry about harmful pathogens finding their way into your plant’s system and wreaking havoc.
Another perk of using a potting mix is the excellent drainage and aeration it offers. This is thanks to the vermiculite, coco coir, peat moss, and perlite it contains.
These components allow the potting mix to retain water just enough to give the roots the moisture they need. They also don’t allow the water to stay for too long, reducing the risk of root rot.
What Should a Good Potting Mix for Indoor Plants Have?
All effective potting mixes for indoor plants have a few essential components in common. Each of these components plays an important role in the growth of your plants.
Perlite
This volcanic glass goes a long way in creating a well-drained and aerated environment for your indoor plants to grow in.
Coco Coir
Coco coir acts as the base material of a potting mix. It has superb water retention properties that prevent moisture from running right through your pot.
Peat Moss
Just like coco coir, peat moss is excellent at retaining water. This makes for a more stable, gradual rate of drainage.
Vermiculite
If you didn’t already know the importance of drainage in your potting mix, you do now.
Vermiculite is yet another water-retaining component of potting mix that improves, you guessed it, drainage.
Fertilizer or Worm Castings
All potting mixes need a source of nutrients, and this is where fertilizers and worm castings come in.
These are potting mix components that provide your plants with the minerals and organic material they need to grow strong and healthy. Worm castings are rich in potassium, calcium, manganese, and many other minerals.
What Are the Best 5 Potting Mixes to Use For Indoor Plants?
There are many great potting mixes for indoor plants available on the market.
Here are five of the best ones:
Wonder Soil Premium Organic Potting Mix
This product from Wonder Soil is probably the best option available. It contains all the essentials, such as coco coir, perlite, worm castings, and kelp. In addition to this, it contains mycorrhizae and a built-in fertilizer.
The former helps protect your plant from a variety of diseases, while the latter provides your houseplant with the nutrients it needs. These nutrients include nitrates, phosphorus, and magnesium.
To top things off, the coco coir in this potting mix expands up to 5x when mixed with water. This means that you won’t have to buy more potting mix any time soon.
Sun Gro Horticulture Black Gold African Violet Mix
As its name suggests, this potting mix is optimized for African violets. However, it works like a dream for most other indoor plants as well.
Its main components are worm castings, perlite, sphagnum peat moss, and volcanic pumice.
You should note that this potting mix leans towards the acidic side. Therefore, you shouldn’t use it with plants that don’t grow well in these conditions. However, it should work just fine with cacti and other succulent species.
Miracle-Gro Indoor Potting Mix
The biggest advantage of Miracle-Gro Indoor Potting Mix is its versatility. This product is an excellent all-purpose option that works well for a wide array of indoor plants. These plants include roses and Monsteras.
Add to that the easy-to-water formula and you have a real winner on your hands!
Another key feature of this potting mix is the absence of compost bark, which is known to attract gnats.
Espoma AP4 Organic Potting Mix
Espoma AP4 Organic Potting Mix is yet another great option to consider. This potting mix offers superb water retention thanks to the perlite and peat moss it contains.
This potting mix’s ingredients also include limestone, which helps regulate the pH level of your plant’s environment.
Noot Organic Indoor Plant Potting Mix
The Noot Organic mix is composed of two core ingredients; coconut coir and perlite. These components create a well-drained, well-aerated environment that’ll allow your plants to thrive.
This potting mix also has a decent amount of fertilizer to cater to your plant’s needs. If you’re wondering what to use it with, think along the lines of orchids, Monsteras, cacti, and succulents.
What Do You Need to Make Your Own Potting Mix?
If you thought your only option was to buy a ready-made potting mix from the store, think again. You can make a potting mix yourself from the comfort of your own home.
Here’s what you’ll need:
- ¼ bucket (2.5 quarts) of perlite
- 1 cup of fine sand
- ¼ bucket (2.5 quarts) of vermiculite
- ½ bucket (5 quarts) of coco coir
- 1 cup of time-release fertilizer pellets
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How to Make Your Own Potting Mix
To make your own potting mix, all you’ll need to do is mix the ingredients above thoroughly.
Note: These quantities make enough potting mix for one 14-inch tub or three 12-inch hanging baskets.
If the containers you have are of different sizes than these, here are some brief guidelines for the amount of potting mix you’ll need:
- 8-inch tub: 3 quarts
- 16-inch tub: 20 quarts
- 36-inch tub: 96 quarts
- 16-inch hanging basket: 10 quarts
What Should the pH Level Be for Indoor Plants?
The optimum pH level for indoor plants is between 6.0 and 7.0. You should keep plants that thrive in slightly acidic conditions at a pH on the lower side of this range.
You can gauge the pH level of your potting mix using a pH meter. If the pH level is too low, you can raise it by introducing powdered limestone to your potting mix.
On the other hand, you can lower the pH level by adding some sulfur.
What Should a Free Draining Soil Have?
You’ve probably heard this term thrown around a lot, but what exactly is free-draining soil?
The best way to describe this soil is with a metaphor. Free-draining soil should handle water in the same way a moist sponge would. When you touch this soil, it should feel moist but not to the point of being sodden.
During the summer, free-draining soil should take up to a week to dry out.
The ability of free-draining soil to retain water at the rate it does is essential. For starters, it allows your plant’s roots to access the moisture they require. Additionally, it doesn’t retain water for too long. This mitigates the risk of your plant suffering from root rot.
For free-draining soil to function like you want it to, it should contain:
- Sand
- Twigs
- Perlite
- Compost
- coco coir
- Peat moss
- Vermiculite
How to Make Free Draining Soil Mix
To make free-draining soil, you’ll need to mix together an assortment of organic materials.
Sand
The first of these components is sand, which drastically improves the drainage capabilities of the soil. Additionally, it significantly improves the soil’s aeration by breaking up any clumps that may form in it to prevent compaction.
Don’t add too much sand, though, because you run the risk of the soil being too dry if you do.
Twigs
You’ll also want to add twigs to your free-draining soil mix. Including some small twigs in your recipe helps with aeration and opens up pathways for the water to access the plant’s roots.
Compost
Another constituent to include in your soil mix is compost. This component makes the soil more moist, especially if you’ve overdone it with the sand.
Coco Coir
Coco coir works as a great base for your free-draining soil mix. It complements the twigs by creating air pockets, improving aeration, and opening up pathways for the moisture to reach the plant’s roots.
Other Ingredients
To round up your free-draining soil mix, you should add some fine-grain vermiculite, perlite, and peat moss to it.
However, keep in mind that peat moss is quite acidic and will lower the pH level of your soil mix significantly. So, you should refrain from using it if the plant you’re growing doesn’t thrive in acidic conditions.
Frequently Asked Questions (FAQs)
Should you use garden soil for indoor plants?
We highly advise against using garden soil for indoor plants as this could lead to a variety of issues. This is because of the pathogens that the dirt in garden soil carries. The other problematic aspect is that garden soil tends to have poorer drainage than potting mixes.
These issues include root rot and the development of mold on your plants. Both of these afflictions can kill your indoor plants.
When to change the potting mix?
Generally speaking, you should change the potting mix of your indoor plants once every 12 to 18 months.
Exactly when you should take this step varies from one case to the other.
One sign to look out for is the water running straight through the pot when you apply it. Another sign is when your plants start to have a yellowish tinge and noticeable growth stagnation.
Conclusion
When trying to optimize the environment of your houseplants, you’ve probably asked yourself what the best soil for indoor plants is.
The answer is a potting mix. The perlite, peat moss, vermiculite, and coco coir this soil contains create the ideal growth conditions for your houseplants. All of these ingredients play a role in improving the drainage and aeration of your plants’ environment.
You can go for one of the commercially available potting mixes we’ve highlighted in this guide. Another option is to make your own potting mix.
Either way, you’ll notice a significant boost in your plants’ growth!