How do you make a gritty, well-draining cactus mix for cheap?
After I bought my first cactus, I fell into a black hole of researching everything I could to keep my new cactus plant happy and thriving. This research very quickly took me on a journey that looked like this: buy a new cactus plant, research the new plant, and repeat.
I did everything right—or so I thought. My lighting was actually terrible. The cactus soil I used didn’t drain well enough and resulted in root rot for most of my first plants.
The answer: gritty cactus mix.
What is Gritty Cactus Soil?
Gritty soil is essentially any soilless mixture made for succulents or cacti. Plants without soil sound strange to most of us, but stick with me!
Picture an area with huge, thriving cacti. You likely see a desert area. Sand stretches out as far as the eye can see, the sun glares in your eyes, and a giant cactus looms over the desolate land.
What you don’t see is soil—there isn’t any. Cactus and succulent plants naturally grow in non-organic materials that hold few nutrients.
We can’t replicate that environment exactly within our homes—or at least I can’t, here in the cold and humid state of Michigan.
But using gritty mix soil for cactus is one step closer to getting the soil conditions with good drainage right.
Bunny Ear by Costel Slincu / CC BY 2.0 Bunny ear cacti in gritty mix soil soil
Why This is the Perfect Succulent or Cacti Soil
A well-draining soil is the perfect one for your succulents or for a gritty-cactus soil. There are a lot of conflicting ideas about this type of soil, but when it comes to gritty cactus oil, drainage is the most important part. This is due to the fact that succulents and cacti have the ability to tolerate dry conditions and drought, and they’re prone to rot if they sit in water.
To successfully cultivate any plant, you have to mimic their natural environment as closely as you can. Wild succulents tend to grow well in gravelly, sandy soil. Many types even thrive in rocky, small crevices or cliffsides. The gritty, native soil tends to get saturated by heavy rainfall, but they also dry out quickly.
There are several variables that will influence how long your soil stays wet. The sunlight, quantity of water, soil structure, and airflow all factor in. When you look at the right soil, you should be aware that you’re trying to get a balance of all of these factors for your drying time.
Since all of these factors come into play, what works well for a friend or family member may not work well for another. So, if you’re an indoor grower with less airflow, you may want a gritter soil to prevent pests. For an outdoor grower in a windy, hot climate, you could use a less porous soil to stop from having to water too frequently.
In non-draining pots, you can drill your own holes in the bottom. You don’t need to add a layer of rock to the bottom because it doesn’t add drainage, contrary to popular belief. Instead, it allows for large pockets at the bottom of the pot where water collects and bacteria breeds. Even the best pot in the world can’t prevent rot from forming if you’re not careful when you water it.
Succulents by mocassinlanding / CC BY-NC 2.0 Getting the soil correct when you plant cacti or succulents is essential for your plants to thrive. When you mix your own, you’re getting complete control of the components to ensure it’s correct.
Why Plants Need Gritty Cactus Soil
Let’s consider how plants have adapted to living in dry environments. Some plants store moisture in their stems and leaves to help them survive through droughts. The plants have an exterior that is used to being warm and dry, even underground. Because desert soil rarely gets soaked for longer periods of time, these plant’s roots don’t respond well to constant moisture levels. If you leave them sitting in water, they’ll start to rot and die.
To protect your plants from suffering from excess moisture, they need well-draining soil. If it’s too wet, the plant can end up with root rot. You want the water to run through the soil quickly so that it’s damp, but it shouldn’t have a muddy consistency. Depending on your plant’s location, your soil will be 100% within 5 to 7 days after you watered it.
Proper gritty cactus soil isn’t all about the dirt. One of the most important parts of growing cacti and other succulents is the drainage holes. If your pot doesn’t have one or two, the water will fill up in the bottom of the pot and soak the roots constantly. As we mentioned, putting gravel on the bottom can’t replace a drainage hole. It just creates pockets for a water table, and bacteria grow here.
Benefits of a Gritty Mix Soil
There are so many benefits to gritty mixed soil, and they don’t only apply to your cactus plants. If you’re like me, you’ll find that gritty mixed soil makes you a happier indoor gardener as well.
- It’s difficult to overwater. I haven’t had a single cactus plant develop root rot since switching over to gritty mix. With a soil mixture that dries out so quickly, it really is hard to overwater your plants.
- It creates less mess. The large particles of gritty mixes are much easier to clean than regular potting soil, which is a plus if you plant indoors—or if you have pets or children occasionally knocking over your houseplants.
- Pests have trouble laying eggs in gritty mix. This is the one thing that officially won me over. Though you’re still at risk of developing pests on your plants, they can’t hide out in between woodchips and perlite in the same way they can in finer pieces of actual soil.
Drawbacks to Gritty Cactus Mix
Of course, we have to also talk about the drawbacks of gritty mix for cactus. Every cactus gardener has different preferences, and a gritty mix isn’t for everybody.
Here are the biggest downsides to consider:
- You have to water more often. I tend toward overwatering plants, so gritty mix is a great solution for me. But if you tend to forget to water, or just don’t want to change your current schedule, you might not like this mixture!
- There are more supplies. If you have limited storage space, having multiple bags of materials might be too much for you. Not to mention, when you do run out, it may take trips to multiple stores to find everything you need. Without a doubt, gritty mix is less accessible than regular potting soil.
- Repotting takes more time—if you weren’t already removing the old soil from your plants. If you were already doing so, it won’t take much extra time at all! Here’s a tip for when the weather’s warm: bring your cactus potting outside and spray off the excess soil with the jet setting on your hose. It works wonders at removing the soil without damaging the roots. I miss this method so much in the winter months.
- You will need to fertilize plants in a gritty mixture regularly. In my opinion, this isn’t a big deal, but it is a bit of a hassle. I use a few drops of this fertilizer in my plant’s water every single time I water. Though succulents and cacti wouldn’t need regular fertilizing in an organic mixture, they do need some added nutrients if you take a soilless route.
Succulents by Ant Smith / CC BY-NC 2.0 Gritty cactus mix has benefits and drawbacks associated with it, and you need to know both so you can make informed decisions when you make or buy it.
How to Make Your Own Gritty Cactus Mix for Cheap
If you’re anything like me, you read about the benefits of gritty potting soil mix for your plants and think about your wallet.
“Sounds nice,” you might say, “but you can’t beat the price of a simple bag of potting mix.”
In reality, I quickly found that your standard potting mixture doesn’t work on its own anyway. You have to mix it 50/50 with a drainage material, like perlite.
When I factor in the additional cost of perlite, I found that I’m not actually spending that much more on gritty mix with the same drainage. The key is finding cheap, accessible materials that work for you.
With that said, I’m going to share my mixture below, along with some alternatives so that you can make your own adjustments. But don’t be afraid to mix it up, experiment, add in new things, or even leave something out entirely. It’s all about finding what works best for you.
Here’s what you’ll need to make your own gritty cactus mix:
- Aquarium gravel, or any other material that doesn’t hold water. Try pumice or grit.
- Lava rocks, or another porous material. Try turface or perlite.
- Bark fines, or another material that retains moisture.
All particles should be 1/8 inch to ½ inch in size.
Orchideensubstrat fein by Maja Dumat / CC BY 2.0 Small bark fines used for gritty mix
Step One: Prepare Your Materials
Wood chips need to be soaked for a few hours, otherwise, they’ll be soaking up a lot of the water that you actually want your cacti or succulents to receive.
If you get a dusty rock like lava rocks, you’ll need to wash these. Make sure you do so outside and don’t breathe in the dust. I recommend wearing a face mask for this. You can also buy pre-washed rocks, which is what I do.
Lastly, sift your materials if needed to get the desired size.
Step Two: Mix Your Materials
I mix my materials together in different ways depending on the plant I’m potting. A chunky cactus potting gets fewer wood chips in its mix and more aquarium gravel than a thin-leaved succulent, for example.
I’ve also had another gardener suggest leaving wood chips out completely, as they’re an organic material. Although my plants are happy with this mixture, you can do what makes sense to you.
Part of the fun is that there are so many ways to make a gritty mix. And, if you’re feeling like it’s too much work to hunt down materials, you can even buy a premade bag of a brand.
Step Three: Pot like Normal
Yes, you’re already done!
Once your mix is complete, you can pot your cactus plants up just like you normally would. The only change that may take time to get used to is that you can’t pack down the garden soil mix as tightly. Your plants might wobble a bit until their roots are established in their new home.
I’ve especially had this problem with cuttings or plants with small root systems. I use wooden barbecue skewers to hold them upright until they can stand by themselves, but in the past, I’ve gotten creative with household items like pens or even paintbrushes. Use whatever works!
Key Succulent Soil Factors
Whether you’re creating your own mix or buying it, there are several key factors you want to consider when you start learning about it. The more you know, the better soil mix you can create for your plants.
Organic Versus Mineral
Soil features organic and mineral parts. So, the organic parts are things that were alive at one point. Minerals are inorganic, natural substances that don’t come from living organisms. For example, plant debris and tree bark are organic components in the soil, but gravel represents the mineral components. Both are necessary in healthy soil. The mineral helps to improve drainage while the organic components provide nutrients for your plants.
The correct ratio of an organic to mineral will help prevent rot while supporting growth. You can water your plants deeply but very infrequently. The mineral content should range between 40% to 80% by volume, depending on which plants you want to grow and the environmental conditions surrounding the plant.
There are several mineral and organic ingredients to pick from, and you can mix several types from each category. A few mineral options include perlite, coarse sand, fine gravel, volcanic rock, and chicken grit. You should avoid minerals that store water, like non-calcined clays and vermiculite.
Wet Gravel by haleyhughes / CC BY-NC 2.0 Gravel is nice to add to your mix to make it lighter and encourage quicker drainage. However, you should mix it in instead of putting layers in the bottom of the pot.
Porosity and Texture
The mineral portions of your soil can be broken down into texture types that get directly based on grit size. The three types range from smallest to largest, including sand, silt, and clay. The portions of each size affect how much water your soil can hold, and it’ll also dictate how long it takes to dry. Since sandy soils have bigger pores and particles, they dry out much quicker than clay-based soil. This is ideal for most succulents.
There are feel tests and jar tests you can perform at home to estimate your soil’s texture. When you plant your flowers outdoors in the ground, you want a sandy loam that is 50% to 80% fine gravel or coarse sand. For potted plants, your grit materials should be between ⅛-inch to ¼-inch in diameter. This will ensure that your soil has quick drainage to keep your plants from rotting due to being too wet.
Why Gritty Soil Works
Succulents and cacti will grow in a variety of soils, but this soil tends to work better than others. Pine bark gives your soil an organic element that helps it retain water, but it also has air pockets for ventilation. As a bonus, pine bark takes a long time to break down. It will absorb some of the water and release it very slowly so the roots don’t sit in water.
Crushed granite lets the water flow among all of the particles in the pot. Since the mix is very porous, water will flow out quickly. There’s also plenty of air in this soil, and this means that the roots don’t sit in pools of water or soggy soil like traditional potting soil. Ideally, you’ll make sure that each particle is ¼-inch in size. It can be very labor-intensive to screen large gallons of gravel.
Mixing this recipe is a challenge and time-consuming, so some people choose to buy a pre-mixed option that is a ready-to-go bag of this soil from Bonsai Jack. The particle size and consistency of this mix are perfect for indoor succulents. You’ll get the ¼-inch size with this mix while others only offer the ⅛-inch particles. It’s especially nice if you’re someone who tends to over-water because it drains very quickly.
However, if you’re not ready to buy this mix and you want to try your hand at making it, you can do so. You can find the ingredients at most nurseries or garden centers. Additionally, you can substitute other ingredients. You have to keep the ratios of inorganic and organic materials the same. For example, if you use another type of bark, you should mix in another type of rock like pumice.
Soil for Outdoor, Potted Succulents
If you want to grow succulents outdoors, on the other hand, using Bonsai Jack Succulent Soil might or might not be a good fit. If you’re not great at remembering water, this mix could be too much maintenance. So, you can use a mix of one part of pumice and one part of coconut coir. The coir works the best to absorb but it drains well after you water it.
It’s also lighter, so your pots won’t get weighed down. You don’t want to use coir indoors as it doesn’t dry out fast enough after you water it. It’s nice outdoors if you live in dry, warm climates. Pumice is also lightweight, and it lets your soil drain faster without drying it out too quickly.
Do Bagged Succulent Mixes at Big Box Stores Work?
If you can’t find the components you need to make your own gritty cactus mix, you can pick up a bag of cactus and succulent mix from your local store. The soil works decently well for your succulents. However, it doesn’t drain very well, and it works to repel water when it’s 100% dry. You should add a rock material like crushed granite, pumice, or perlite to allow it to drain better.
Using Perlite for Succulents
You can add perlite to your succulent soil mix to help it drain better and be lighter. Perlite will crush easily, and this could be a potential downside. So, it’ll eventually break down into a fine powder. However, you’ll want to refresh the soil every few years, and you can replace the perlite each time you do to get the most use out of it.
Using Pumice for Succulents
Pumice is a very popular additive in succulent soil. It’s much more durable than perlite, and it can last longer, even if you don’t refresh the soil. You can plant your succulents exclusively in pumice, but you’ll want to be very careful about how you water to ensure you don’t overwater the plants. Pumice is extremely porous, and it’ll trap water in dozens of small holes in each particle.
Pumice can work well for succulents because it doesn’t feel wet like you’ll get with traditional potting soil. It allows for more airflow around the particles, and this is very similar to the gritty mix we outlined above. You will need it to completely dry before you water it again to ensure you don’t overwater it.
Sand Mixed Into Your Succulent Soil
You can also use coarse sand in your succulent soil recipe. However, you want to ensure you work for ¼-inch particles or larger. Using a very fine grain sand similar to beach sand can prevent the soil from draining as well because it’s so dense that your plant’s roots can suffocate.
Repotting New Succulents in New Gritty Soil
As soon as you bring a new succulent home, you want to repot it in new soil as soon as you can. You’ll remove most of the soil from the original pot. A lot of problems that arise with succulents come from keeping the succulents in the soil that they came with from the store.
There are two main issues with the soil that comes with your succulents from the store. First, any succulents that you buy locally are usually root bound with the roots filling up most of the pots. If you just remove the succulent and put it in a new pot, the roots will have a very hard time spreading out and growing.
The second issue is that most nurseries sell succulents in soil that doesn’t work well for long-term growth, or long-term growth out of a greenhouse. Large growers and nurseries generally use the same soil for every plant. They want a general soil mix that will work with everything. When succulents are small, they need to have more water. So, having a dense soil will work at this stage.
Leaving your succulents in soil for too long can cause your succulent to rot. It could also prevent it from getting the correct amount of water it needs to grow. Peat moss is the biggest ingredient in many types of potting soils, and it tends to repel water when it dries out completely. If you don’t let your water sit on top of the moss and start to soak in, the plant won’t get any water. Instead, the water will run down the sides of the pot and out the bottom. So, replant them as soon as you can after you purchase them in your gritty soil.
Gritty Cactus Soil – Frequently Asked Questions
Succulents! By Kimberly McKinnis / CC BY-NC-ND 2.0 When you’re mixing your gritty cactus soil, it’s not unusual to have questions about the process or the ratios. We’ve rounded up a few commonly asked questions for you below about this soil to give you a better understanding of how it works.
1. What do you mean by gritty soil?
Gritty soil refers to any soilless mixture that is specially made for cacti and succulents. These plants typically grow in non-organic materials that hold very few nutrients and drain very quickly after you water it.
2. What are the three main components of soil structure?
You can categorize the particles that make up your siol by three groups according to size. They include sand, silt, and clay. Sand particles are the biggest and clay are the smallest. Most soils contain an amount of all three. The relative percentages of each of the three components are what give soil its texture.
3. Which soil absorbs the most water?
Loam will absorb the most water each time you water your plants. Clay soils will retain the most water, so you want to avoid both in your gritty soil.
It’s possible to mix your own gritty cactus soil that is great for a huge range of succulents. We’ve given you a recipe, a pre-mixed option, and told you about amendments to the soil. You can use this information to keep your cacti and succulents healthy and thriving for years.
Jen is a master gardener, interior designer and home improvement expert. She has completed many home improvement, decor and remodeling projects with her family over the past 10 years on their 4,500 sf Victorian house. She is also a passionate farmer who keeps goats, chickens, turkeys cows and pigs on her farm, and an instructor for her community’s Organic and Sustainable Farming project.