I have been researching extensively about cactus and how to grow them healthily. One thing I have discovered is you need the perfect soil mix for a longer lifespan. When you are purchasing your cactus, you don’t need the ideal plant but also the right soil mix for better results. I went on a pursuit to knowing how to get the perfect soil. Stick around for my findings.
Cactus is commonly referred to as a desert plant, but it also grows in tropical rainforests. The idea when purchasing a cactus is trying to mimic its previous growing conditions. One of the ways to do that is ensuring you have the right potting mix.
Starting with the right kind of potting mix will be easier as it will make work easier for you. Naturally, cactus are not high-maintenance plants.
Type of soil a cactus needs
A cactus will require soil that’s pebbly, sandy, porous and one that provides excellent drainage and aeration. The right type of soil will need to dry quickly after you water the plant. The mixture should also be able to meet the nutritional needs of the cactus.
Cactus need a potting mix that’s ideal for them.
What is a cactus mix?
Cactus mix is soil specially designed for growing cactus. The mix is available in garden centers and most nurseries. You have the option of purchasing the mix or making one on your own. The right kind of combination has superior drainage qualities and quick dry out time upon watering.
What happens is, when you water cactus, they take in all the water they need and store it. Therefore, there is a need for good soil that drains well so that it can drain the excess water. This will prevent root rot and fungal infections.
Commercial mixes (those you purchase) are designed in a way that they use the elements where these plants grow naturally, and they then add peat which holds moisture. When the peat absorbs moisture and then dries out, it rarely soaks in water which leaves the pot dry.
Alternatively, you can create a homemade mix customized for your plant. Sometimes, one mix doesn’t fit all cacti species, and yours may be different from the ones at the local store. It also depends on your location and what the cactus is used to. For example, you can not use the same mix for tropical and desert cacti as the living conditions are a bit different.
Why you need a good cactus soil
You probably are aware of how cactus have adapted to their harsh conditions on how to store water through their waxy coatings and succulent tissues.
The desert cactus roots have also adapted, which is why you need a potting mix that can dry out quickly.
Cactus roots are susceptible to rot when they soak in excess water. They can store water for long through their shallow roots that spread away. The root formation helps them take in enough water to take them for a long time. The roots can adapt quickly if there are any changes in the water supply.
Due to the way they are, they quickly collect water but can be quick to rot, especially if they are planted in a pot and don’t have the right cactus soil mix. It is, therefore, crucial to making sure your soil mix is up to par with their requirements.
Before we start, here is a list of our favorite and recommended soil mix (Here)
Tips To Choosing The Perfect Soil For Your Cactus
After you buy cactus, you need to know what to look out for when choosing the soil mix. Below are some pointers to getting the desired soil for healthy cacti:
1. Organic vs. Inorganic matter
Organic matter helps the water to penetrate the soil quickly. Peat moss, ground coconut fibers, and ground bark are some examples of organic matter.
The only downside about this is that it has a possibility of retaining too much water. There are soil mixes that contain peat moss such as Perfect Plants, Miracle-Gro, and Hoffman.
Inorganic matter is ideal and helps keep the soil well-drained. Some of the ingredients are sand and perlite.
2. The soil composition
A well-drained cactus soil
The main cause of cactus not thriving is the issue of overwatering them. Some common signs of overwatering are:
- The leaves start changing color
- The roots rotting
- The base starts turning pale/black
When purchasing your soil, you don’t want one that will retain too much water such that your cactus ends up dying.
An ideal soil composition should be pebbly and gritty. One that drains well and is aerated. Also, the particle size ingredients need to be ¼ inch so that there is free airflow and moisture is easy to control.
Soil with the right PH
The most significant advantage of using a purchased potting mix for growing your cactus is the fact that they are specially designed in a way that they have the right PH. The soil you use should have the correct PH. You don’t want soil that’s too acidic. A soil with a PH of 5.5 or 6 is excellent and will be right for your plant.
Sometimes, if your cactus is not growing, it could be because there is no PH balance. It could also be because the soil has water, which raises its alkalinity. The plant may not be growing because it doesn’t absorb the much-needed nutrients for its health.
Using rainwater is ideal because it will keep the soil PH balanced.
There are types of PH testers available in the market where you can test your soil to ensure it has the right PH.
Testing soil PH
I. Using a commercial test probe
First, dig a hole and break off the soil to remove any debris. Using distilled water (available at your local pharmacy) fill the hole until it’s muddy at the bottom. Using your clean probe, insert it into the muddy pool and hold it for 60 seconds then take your reading. The tester is usually on a scale of 1-14.
If the PH is 7, it is neutral. If it is above 7, it is alkaline, and if it’s below 7, it is acidic.
| Soil PH | Below 7 | 7 | Above 7 |
| Acidic | Neutral | Alkaline |
II. Using PH test strips
Test strips are also known as litmus paper. You can purchase them at the garden store. To test the soil, pick a small portion of your soil and mix it with distilled water in a bowl, and then stir to ensure the mixture is even.
Holding the non-reading end, dip your test strip into the mixture for about 20 seconds. Always refer to your test strip as this time may vary depending on the strip type. Once the time is up, you can then dip the strip briefly in distilled water to dilute the dirt.
Using your key that comes together with the test strip, check what color is close to the results. The color will be in the form of numbers where you can translate your results.
It is also possible to change your soils PH by lowering to make it more acidic, which is ideal for growing cactus. Mix your soil with one cup of organic matter such as decomposed leaves or peat moss. Keep testing and adding organic matter until it reaches your desired level.
3. The soil ingredients
What the soil mix contains is what determines if the cactus will grow healthy or not. Choose the appropriate soil combination.
Some of the common elements in the soil are:
The Japanese hard akadama
Just as the name suggests, its origin is Japan and is exclusively mined there. It is a clay-like mineral that’s used as soil for potted plants. It can act as one element that can be combined with others, such as sand to give a rich soil mixture. The akadama can retain water and nutrients and can break down, allowing the roots to grow and avoiding water from staying around the roots hence reducing risks of root rot.
Pumice
Pumice is a volcanic rock in the form of lumps. Due to its numerous gas bubbles, it floats on water. The reason why pumice is excellent as a cactus soil ingredient is because it is porous. It is used as an additive for potting mixes so that there can be great drainage conditions for the plants.
It is loose and with a lot of space for the roots and air. With high drainage, it leaves enough space for air so that it retains enough moisture so that it reduces the number of times you water your plant to reduce the chances of root rot.
In most cases, a potting mix will contain 25-30% of pumice.
Perlite
Perlite is usually a form of volcanic glass mined globally and is white. It has high water content and can be used to make potting mixes for cactus and other succulents that don’t require moisture. Perlite has a neutral PH and is best known for its aeration qualities.
Using perlite helps as it retains moisture and drains any excess water making the soil dry and great for the cactus as they don’t thrive in water.
Vermiculite
Vermiculite is hydrated laminar minerals. In most cases, it usually has a PH of 7, which means it’s neutral. It’s light and easily mixes with the rest of the ingredients in the soil. The medium, as compared to the rest, is better at water retention and soil aeration. Below are some of the uses of vermiculite.
Vermiculite uses
- It can be used for growing plants where it’s easier for them to absorb calcium, magnesium, potassium, and ammonium, which are all required for accelerated growth.
- You can add it to soil together with peat for soil lightening and conditioning to promote the growth of the roots.
- Mix half vermiculite and half soil in potted plants as it does away with any excess water and is perfect for aeration.
- Vermiculite can be used alone or mix with some soil or peat for seed germination. In the case that you use the vermiculite alone, make sure you pour in some weak fertilizer after the first leaves appear.
- It is also used when transplanting. Carefully dig a hole that’s larger than the plant roots and fill it with vermiculite and the topsoil you had removed when digging the hole. This helps the roots spread and control excess moisture as well as protecting the roots from completely drying out.
- The medium grade one can be used for root cuttings directly. You just need to water thoroughly.
- You can use vermiculite when arranging flowers. Fill your pot/container with vermiculite and saturate it with water. Pour off the excess water and arrange your flowers. There will be no need for changing the water, and it will keep your flowers fresh all day. Be sure to use the horticulture vermiculite though.
New Zealand pine bark
Also known as Enzogenol, it is a 100% natural extract found in New Zealand pine trees. The bark can last for years when used in pots without breaking. It holds water which makes it perfect for cacti and other succulents.
Haydite
Also known as expanded shale, it absorbs any excess water and eventually releases it slowly to the roots. This way, there are no issues of the cactus roots rotting.
Coco coir and composted rice musks
These two are among the best organic matter to include in your potting mix. What makes them perfect is that they are long-fiber that absorb excess moisture and dry out quickly as well. They last long, have good nutrient bonding properties and are rot-resistant.
Sand
In most cases, sand is used to ensure the soil drains well. You can mix gravel and grit into your potting mix for better drainage. If you decide to use sand, make sure you use construction sand since it’s coarse and inexpensive.
4. Researching on the commercial potting mixes in the market
If you decide to go with a commercial potting mix at your local garden store, you’ll need to choose the best. There are numerous ones in the market, and some are specially designed for cactus. However, some may not be the best for your indoor plant, and upon purchasing, you may need to add some pumice or any other coarse material. This improves soil porosity.
If you are not quite familiar with making your own cactus potting mix, then purchasing the commercial mixes is a better option for you. Some of the best-known mixes are Hoffman Organic Cactus and Succulent Mix, Cactus mix with Mycorrhizae from Green Planet Naturals and Espoma Organic Cactus Mix.
The best potting mixes will always have good drainage as well as an excellent water-holding feature. They will also not dry out completely to leave some moisture for the roots when they dry out.
Cactus will absorb the water quickly and store it in their bodies while the excess water drains out through the drainage hole of the pot/container.
This is why it’s crucial when buying a pot, consider if it has drainage holes. You need one that has so that water drains out. This way, there is no excess water left hanging around to cause root rot.
The potting mixes available have the basic elements of a potting soil, which is why you need to add peat moss to create an overall better mixture. These mixes will usually grow the cactus from propagation all the way to maturity.
5. Knowing what type of cactus you purchase
As mentioned, cactus live in either arid or tropical areas. Determining what kind of soil is ideal for your cactus first needs you to identify your cactus type.
Tropical cactus
Tropical cacti are found in places such as the South American jungles. Since they are epiphytes, they grow attached to the trees. Such species are the Holiday Cacti such as the Christmas Cactus. These cacti are soft and have spineless leaves, unlike the arid ones.
Even as the tropical areas are rainy, cacti drain freely because they hang on the trees; hence, their roots never rot. As such, they need evenly moist soil but one that does not become waterlogged. They need one that drains effectively.
Generally, all cacti species require well-draining soil. However, for tropical cactus, they need soil with more organic matter.
You can mix 1 part of garden soil to 2 pieces of peat moss and 1 part of sand.
Arid cactus
Even as most cacti grow in desert areas and bear fruits and flowers, they are mostly grown for their shapes, sizes, and colors. In recent years, research has also shown the health benefits of cactus fruits and pad (nopals). From weight loss to healthy hair, the benefits are quite numerous.
They have spines that are a protective way of keeping away predators. However, there are still some daring animals such as camels that eat them even with their spines. They usually have hardened structures in the mouth known as papillae that help protect them from scratches of the spines.
Arid cactus need dry soil as they are used to in the desert areas. They hate waterlogged soil, which is a common cause for root rot. Making your mix can be helpful, and it’s recommended you use 1 part soil mix and 2 parts of sand so that you provide the right growing environment for them for proper drainage.
6. Consider the option of making your own potting mix
Instead of purchasing the usual commercial potting mix, you can make your potting mix. You get to customize it for your plant. The first step is getting a container big enough to hold all the ingredients without any spillovers.
Here are some sample recipes for making a cactus potting mix.
Ingredients:
- 1 part builder’s sand
- Four parts bagged potting soil
- Five parts perlite
- A pinch of rock dust
Make sure the top part is dressed with aquarium stones or pea gravel.
Recipe for the desert cactus
If you plant cactus in pure sand, it will not thrive well. Therefore, get a rich-nutrient soil that’s rocky that is in a pot that has adequate drainage holes. Nutrients you need will include peat moss, perlite/vermiculite, coconut coir, and pumice. All of these combined make the perfect potting mix that’s great for aeration and drainage.
To start, use ordinary potting soil as your base. Then add 2 parts of pumice as it is a volcanic rock which is porous and is light. In case you don’t get pumice, chicken grit can be a great substitute. Check for oil dry number 8822. You can also substitute with perlite or vermiculite. This is a crucial stage because water quickly passes the potting mix while still providing aeration.
Next, pour in some coconut coir as it gradually decomposes. The upside for this is that it helps the cactus mix hold moisture.
Recipe for jungle cactus
As earlier mentioned, the potting mix you use for desert cacti is not what you’ll use for the jungle ones. Since jungle cacti are epiphytic, which means they can grow literally on rocks, you’ll need a well-customized mix.
This means that they can get nutrients from dead leaves. They can even get their needs from the air, which is great.
The idea is to try and mimic those living conditions in your potting mix. Try to make it as natural as it can be. For this, you need a combination that has coconut coir, orchid or fir bark, peat moss, oak leaf mold, and pumice.
The mix will be almost similar to the dry soil mix but change up a bit. You need 1 part pumice and 2 parts orchid bark (coarse.) This potting mix provides more aeration, which makes it the perfect blend for your tropical cactus.
Another alternative for tropical and arid cactus
Ingredients:
- Ground fir bark
- Bucket
- Coconut coir/peat moss
- Vermiculite/perlite/pumice/coarse sand
In the bucket, mix equal portions of peat moss and ground fir bark. This creates an ideal base mixture for both desert and tropical cacti. As an alternative, instead of using peat moss, you can use coconut coir or leave out the ground fire bark.
Next, mix the base potting mix you made with one part of the coarse builder’s sand. This is applicable to the tropical cactus as they need more moisture and can tolerate slow water drainage as compared to the desert species. Alternatively, you can use perlite, vermiculite, or pumice instead of the coarse sand.
For the desert cactus, use equal portions of the base potting mix and the coarse sand or pumice/perlite/vermiculite. They do well with a mix that drains water quickly and can’t stand too much water retention.
After the above, mix all the ingredients until they are uniformly combined. In the case that there are any lumps formed, blend the soil until it is even.
The last step is equally as important. Before you plant the cactus, water the mixture to allow the peat or coir to absorb the water, do this for approximately an hour. Squeeze the soil to make sure no water droplets are running down to be sure it’s safe to plant the cactus.
Sometimes, you’ll need to add 1 tablespoon of vinegar to 5 gallons of water when you are watering to raise the soil’s acidity slightly.
Note that there is no specific recipe that is ideal for everybody. The best one for your plant will depend on your preferences and your plant. The recipes above are to guide you so that you can create a well-balanced mixture.
Characteristics of an excellent potting mix
The soil needs to drain fast to prevent the cactus roots from rotting. An excellent remedy for root rot is re-potting and cutting the damaged roots carefully.
The potting soil should also be able to retain some moisture so it can provide when the plant dries out.
Get one that is rich in nutrients that contain porous inorganic materials for proper drainage and part of it having organic materials that will provide nutrients to the roots when they need them.
Even as you use regular potting soil, ensure you add a bit of pumice to improve the soil’s ability to drain water effectively.
The above points should help you make a decision when you want a potting mix for your cactus. If you wish to purchase the mix or make your own, the guide will help you. Also, remember, even after you make the potting mix, you will need to re-pot them ideally every two to four years. Once the roots start showing through the drainage holes, it is time to re-pot them.
Here is a list of our favorite and recommended soil mix (Here)
Last update on 2023-07-26 / Affiliate links / Images from Amazon Product Advertising API
