How to Make Well-Drained Soil for Houseplants

Figuring out how to make well-drained soil for houseplants can make all the difference in their growth. For starters, it’ll prevent waterlogged soil, which brings about many problems like root rot, droopy leaves, and even death. So, how to make houseplant soil drain better?

A good soil mix for indoor plants mainly contains an organic part, like peat moss or coir, that makes up most of the soil. A drainage-enhancing mineral component and compost to enrich the soil make up the rest of the soil mix. Mulch is also functional in improving soil drainage.

In this article, we’ll discuss six tips that help you make well-drained soil for your houseplants to support healthy growth. Keep on reading for all the details!

1.   Choose the Right Soil Texture

The right soil texture

Most houseplants prefer lightweight soil that retains moisture yet drains well. The soil should have enough air space to allow proper root aeration as well.

However, you should consider each plant’s nature when choosing the right soil texture.

For instance, succulent plants prefer a more sandy texture that doesn’t hold much water. So, you might need to use less moisture-retaining components like peat. Alternatively, you could add sand into the mix to create the right soil texture for succulents to grow.

That said, steer clear of garden soil for houseplants. Yes, garden soil and potting mix are two different things. The former contains dirt (sand, loam, and clay), while the latter often doesn’t.

For potted plants, garden soil is compact, holds moisture, blocks aeration, and doesn’t retain nutrients—all of which will stop indoor plants from thriving.

2.   Start With 4 Parts Organic Material

Organic materials make up most of the ingredients in indoor potting soil, whether it’s a commercial potting mix or a DIY mix.

That’s because these plant-based materials achieve the goal of ensuring your plants get plenty of water, nutrients, and air while draining the excess too.

Sphagnum peat moss and coco coir are popular choices gardeners use to make houseplant potting soil.

Let’s discuss each substrate in detail!

What Is Sphagnum Peat Moss and How to Use It?

As the name implies, peat moss comes from a group of plants known as sphagnum. Interestingly, producing peat moss involves decomposing plant material in wetlands (bogs), which is then dried and shaped into bales for commercial use.

Aside from its water-holding capacity and aeration, sphagnum moss helps neutralize alkaline soil or slightly acidifies it. That property makes it ideal for indoor plants, since most indoor plants thrive at a pH of 5.5 to 7.5.

Still, peat moss has some shortcomings. The biggest flaw of peat moss is its unsustainability. Once harvested, peat moss destroys beneficial microorganisms in bogs, causing environmental damage. Plus, it reduces the chances of regrowth.

Another often irreversible flaw of peat moss is that it doesn’t absorb water once it dries.

Peat moss should make up half of the soil potting mix. For instance, if you make a four-ingredient pot soil that contains two parts compost, you’ll need to add four parts of moss.

What Is Coco Coir and How to Use It?

Coco coir

Unlike peat moss, coco coir is a more eco-friendly and sustainable option. It comes from coconut husks and is also a product of plant decomposition in landfills.

Coco coir provides the same impressive water-holding capacity and aeration properties as peat moss. Similarly, coconut coir should make up half the potting mix. The only drawback to this organic material is that it’s not as available as peat moss.

To prepare coco coir for the potting mix, all you need to do is place the fibrous brick in a tub filled with warm water. Then, let it sit for a minimum of 15 minutes or as instructed on the label. After hydrating the brick, break it with your hands until it feels light and spongy.

3.   Add 2 Parts Compost

As mentioned earlier, moss and coir are responsible for the texture and contain no nutrients. So, it’s only natural to add compost to the potting soil when feeding the houseplants.

Whether you’ll DIY or buy compost, you shouldn’t put more than a third of the total potting mix.

That’s because too much of this nutritious material builds up minerals in the soil, negatively affecting plant growth. So, if you use four parts of organic material (moss and coir), you should add about two parts of compost.

Now, you might be thinking, what does compost have to do with soil drainage?

The answer is that it introduces soil bacteria to the potting mix. These beneficial microbes secrete substances that bind soil particles together, forming stable soil aggregates. As a result, it creates air voids in the soil that allow oxygen entry and water infiltration.

Read more: How to Make Houseplants Grow Faster? (6 Tips)

4.   Mix In 1 Part Mineral Product

Adding mineral compounds, like vermiculite and perlite, improves soil structure. Both compounds hold water and improve soil drainage—it sounds odd, but that’s what makes them good additives for potting mix.

However, vermiculite and perlite aren’t interchangeable, so which one to choose?

Vermiculite is a silvery, spongy mineral product. When it gets wet, this spongy mineral expands and can hold water up to four times its volume. As a result, it prevents soil from becoming compact, maintaining good aeration.

All those characteristics make vermiculite ideal for water-loving houseplants like prayer and arrowhead plants.

Perlite, on the other hand, is a more porous mineral. It also expands when wet and holds water well, but not as much as vermiculite. They hold air thanks to their pores too.

Those small holes make perlite better at water drainage than vermiculite. A property that makes perlite suitable for indoor plants that don’t prefer high moisture, such as cacti.

Whichever option you choose, you should add one part of these mineral compounds to the potting mix.

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5.   Add 1 Part Worm Casting

Worm casting (vermicast) is a natural by-product of earthworm soil decomposition. Vermicast is loaded with nutrients, making it an excellent soil amendment.

While the earthworm by-product is usually used for outdoor plants, a small amount can still improve the potting mix quality and structure. Thanks to the organic matter this amendment holds, it feeds beneficial soil bacteria. Consequently, it improves soil drainage, as mentioned earlier.

The above reasons make vermicast a great addition to your potting mix. Just make sure to keep the worm casting volume between 10% and 40% of the total potting mix.

6.   Mulch the Soil

Mulch the soil

Adding mulch to the soil brings about many benefits. It helps retain moisture, improve aeration, and regulate the soil temperature. Plus, it can suppress weed growth!

Typically, mulch can be either organic or inorganic. Each has its pros and cons. As you might have guessed, organic mulch will decompose over time, adding nutrients to the potting soil. On the other hand, synthetic mulch lasts longer and is better at retaining water.

Either mulch option will add value to the soil. To get those benefits, all you need to do is spread a layer of around an inch or two on top of the soil mix. That said, make sure not to use sour mulch, as it’ll do your plants more harm than good.

Conclusion

So, how to make well-drained soil for houseplants?

To make the ideal soil for houseplants that drains well, start by mixing four parts of lightweight organic material, like peat moss or coco coir, with two parts of compost to feed the plants.

Then you should pour in one part each of vermiculite or perlite. Mixing worm casting for added moisture retention, drainage, and nutrients is a plus.

Combine that with a layer of mulch on top of the potting mix, and you can reduce the chances of waterlogged soil.