Pebbles, like cacti, come in all shapes, sizes, and colors. And, just like cacti, they need lots of water to grow big and strong. But, adding pebbles to your cactus soil can help a cactus grow faster and absorb more nutrients.
Cacti are very resilient plants that have adapted to growing in all sorts of harsh conditions. Since there are so many different cacti, we humans have domesticated them in a way, and now many of us love to keep adorable little succulents and cacti in our gardens.
They’re wonderful to look at and come in interesting shapes. Since they are not as fragile as most other plants, we find it easier to take care of them!
We’re sure you have seen people put pebbles on top of cactus soil in their gardens and wondered why. Any responsible cactus parent would also wonder if they should start putting pebbles on top of their plants too!
If this is the case, keep reading to figure out why and if you should put pebbles on top of your cactus soil:
Table of Contents
Why Should We Put Pebbles On Cactus Soil?
There are many reasons why pebbles on top of your cactus soil can make your cactus grow better. Here is why you should try putting pebbles on cactus soil:
Soil Drainage
The main reason you should add gravel or small pebbles to the cactus soil is that it encourages better soil drainage.
Cacti and other succulents have evolved to grow in hot, dry conditions where the soil is sandy and contains minimal moisture.
The soil mixture we usually get in the market is not that dry and adding sand to our cactus pots will make it super inconvenient when even the slightest wind blows!
Leaving cactus roots in wet soil will cause them to rot easily and make the plant susceptible to pest attacks as well.
The small pebbles above the wet soil will be able to drain the water quickly so that the roots of the cactus are not submerged in a wet environment for a long time.
The spaces between the gravel are bigger than the space between sand, and therefore water passes by those spaces quickly, causing ideal conditions for your cactus’s growth.
Anchoring Roots
Since cacti are so resilient as plants, many don’t even need soil to grow. Many cacti can simply grow on bare rocks!
However, all cacti have roots, and they need a medium to hold or anchor their roots to ensure the cactus grows with stability.
If the soil is too nutrient-dense or watery for some cacti, you can use pebbles instead to hold together the roots of that cactus to provide it a stable medium to grow in.
Once a cactus has been planted inside a pot with pebbles, the roots will find ways to grow around the pebbles and stabilize themselves in the soil.
They look Great
There is no denying that pebbles holding your cactus can be one of the most aesthetically pleasing sights.
Pebbles come in all sorts of colors and sizes and add a lot of aesthetic value to your garden.
Gravel and pebbles also impart a slightly different look to the garden than other plants, which adds some range and diversity to the garden.
If you think your garden is too monotonous and could use a splash of something different, putting small pebbles on the cacti in your garden can be a perfect idea.
Additionally, many pebbles also come in different colors, which can complement the rest of the garden. You can also stain or tint the pebbles yourself in fun colors to add some variety to your garden.
All in all, it is a great idea to put gravel on top of your cactus’s soil.
What Type Of Rocks Can We Put On Cactus Soil?
You can simply run to your nearest horticultural store and get a bag of any gravel and we can assure you that your cactus will still grow on it.
However, if you really care about your cacti and succulents, the type of rocks you use for the gravel is crucial.
Not all rocks are the same, and not only will these gorgeous rocks make your garden look like a million bucks, but they will also ensure the healthy growth of your cacti and succulents.
Some of the best rocks for your succulent garden can include the following:
- Red Lava Rock: This type of gravel is perfect for topping the soil on your cactus. The reddish tint of these rocks adds vibrancy to your garden, and they are great for draining water from the stem of the cactus. You can even add this rock on top of other crushed pebbles to enhance the stability and nutrition of your succulents.
- Mexican Beach Pebbles: These are small pebbles that come in a vast range of colors and can really add a vibrant splash to your succulent garden. They are small and uniform so they can also hold the cactus’s roots in place.
- Arizona River Rock: These small rocks are perfect for indoor succulents, especially those that do not need a lot of water or nutrient-rich soil.
- Criva Pebbles: These pebbles are also perfect for indoor cacti and succulents.
- Desert Gold: These small crushed stones come in various hues of colors that bring out the vibrant hues of your cactus. They are also porous and can hold some water while allowing for sufficient drainage.
- Gambler’s Gold: These rocks come in interesting shades and hues and can greatly accentuate the look of your succulent garden. They are also great for adding stability to the roots of the cactus.
Additionally, the types of rocks you use for your cactus also matter in other regards. For example, dark-tinted rocks store more heat and could be perfect for cold climates.
However, you should avoid using dark rocks for hot climates since they may scorch the roots. Stones and pebbles store more heat than soil too. You should use lighter stones such as Gambler’s gold for hot areas.
You may also find a variety of rocks in different colors and textures to make your succulents stand out. You may even want to mix and match the colors and textures to complement each other and make the most out of your cactus garden.
What Cacti Grow Best On Pebbles?
Most cacti can easily grow on a topping of pebbles on soil, but this arrangement works better for some cacti than for others. For example:
Yucca
Even though Yucca is not a cactus, it is succulent, and it can easily grow on a top-dressing of gravel or pebbles in soil.
Yucca typically has sharp, pointed leaves, which can easily scratch and puncture the skin. It uses these sharp leaves to keep predators away.
Prickly Pear Cactus
Prickly pear or beaver cactus has succulent blue-green pads and cherry red flowers. It is also known for giving the prickly pear fruit, which is widely enjoyed by so many of us.
This type of cactus also requires quickly draining or sandy soil, which provides the cactus with ideal growth conditions.
Peanut Cactus
This is a small cactus that rarely grows beyond 1 foot in height. They also bloom red and white flowers with a yellow center.
The peanut cactus requires quick-draining gravel and gritty soil to grow, making it the perfect cactus to grow on pebbles.
Candelabra Cactus
These cacti can grow super tall, up to ten feet, and grow best on slopes and hills. These cacti are super resilient and grow in the driest soil.
They bear flowers and edible fruit. This cactus can grow perfectly on pebbles, gravel, or small stones.
Whortleberry
This blue-tinted cactus can also grow very tall, up to 15 feet, and grows wide and dense, creating almost an ecosystem.
It also bears flowers and purple fruit, which tastes sweet. This cactus is also very resilient and can grow in dry soil and on gravel and pebbles.
Can Cacti Grow On Rocks?
Some cacti can also grow on huge, bare rocks and sustain themselves. These cacti have roots that can easily penetrate the rock and help the cactus sustain itself.
So yes, some cacti can also grow on rocks and sustain themselves with barely any nutrients. However, it would be difficult to replicate this in your succulent garden! You cannot put a huge rock in a pot and expect a cactus to grow there!
So even though this phenomenon is true, it only happens in deserts and other areas with little to no nutrition.
Can We Grow Cacti Without Soil?
Some cacti can grow without any soil on crushed rocks or small pebbles. The blue flame and candelabra cacti are prime examples of cacti that need little to no nutrients in the soil to grow to be huge, healthy plants.
Other cacti can also grow on small pebbles if some cactus mix or soil is introduced into the pebbles.
However, it is very difficult for cacti to survive for long on just gravel, and it is very difficult to maintain most of these plants as well.
Firstly, you will have to constantly water the pebbles to make sure that the cacti do not become under-watered.
This is because water drains from pebbles much quicker than it does from the soil. So the faster the water drains, the more water you will have to add to the mix.
Secondly, some cacti also have fragile roots which cannot hold their own on pebbles. These cacti usually do not grow to be healthy plants and die quickly because they are not grown in proper soil. Therefore growing many cacti without soil is not a great idea.
If you want to grow cacti on pebbles or gravel, you will have to keep adding water, fertilizer, and other substances to make sure that the plant grows healthily.
You can also add organic materials such as rice hulls and worm castings or other substances that provide the gravel with phosphorus, potassium, and nitrogen.
Benefits Of Pebbles On Cactus Soil
We know that cacti can grow in soil alone just as well as they can with pebbles. So is there any benefit to adding gravel or pebbles to the cactus soil? Let’s find out:
Encourage Healthy Cactus Growth
The soil mix in the pot has all the essential nutrients that can ensure the cactus’ proper growth. However, this soil can quickly become moist and hold a lot of water, putting the cactus in danger of being overwatered.
With the help of a pebble topping on the soil, the water can drain quickly and especially be away from the drier parts of the cactus, such as the stem.
This mix of the two will therefore encourage the healthy growth of the cactus.
Prevent Overwatering
The well-draining pebbles on top of the soil can also help keep the cactus from being overwatered.
The spaces between the pebbles are large and allow the water to pass quickly, preventing the cactus from being submerged in moisture for too long.
This will ensure easy maintenance of the cactus since you will not have to check to see if the cactus is doing well constantly.
Prevent Rotting
Overwatered cactus stems and roots can easily begin rotting if the water is not drained quickly enough.
This makes for the stunted growth of the plant, and it can even kill the cactus fairly quickly. Sometimes, these plants can even grow mold, eventually making it rot.
Therefore, adding a gravel mix or grit to the soil as a precaution can also encourage the plant to grow healthily and prevent it from becoming contaminated or rotting.
Prevent Pest Attacks
Pests such as fungus gnats attack over-watered cactus roots. Not only that, but moist soil can also harbor different pests and their larvae.
These pests can start feeding on nutrients from the cactus’s stems and roots, preventing ideal nutrition from reaching the cactus.
Most pests do not attack pebbles and hard rocks. Therefore, a topping of pebble mix will also help keep pests away from the cactus, making it grow healthy and strong.
Great To Look At
Pebbles also offer excellent aesthetics for your garden. They come in a variety of shapes and hues, which can help add splashes of color to your succulent garden.
Most cacti also bear vibrant and colorful flowers. These, paired with the different colored pebbles, could make your garden look absolutely gorgeous.
With the help of pebbles, succulent gardens can actually look more vibrant than regular gardens.
Looks Cleaner
Soil can be quite messy. If it spills or if you break a pot, the soil would cover the ground and take away from the neatness of your garden.
Pebbles look much neater than soil. They are bigger and come in more uniform shapes, which help the garden look neat and tidy. Pebbles are also easier to clean up than soil.
Add Variety To Your Garden
Pebbles can also help in growing an entirely new ecosystem in your garden. You can plant different varieties of cacti or succulents in each bed, which means you will not be limited to caring for just one plant at a time.
The pebbles can also grow moss, algae, and other simple plants, which can add variety to the plants growing in your garden.
Disadvantages Of Growing Cacti On Pebbles
There are some disadvantages to using pebbles to grow cacti as well. Some of them include:
Insufficient Nutrients
Pebbles do not contain as many nutrients as the soil does. While the soil under the pebbles may be nutritious for the plant, the pebbles may prevent some of those nutrients from reaching the plant.
To prevent this problem, you need to make sure the proportion of pebbles to soil is accurate. Too many pebbles and too little soil can do more harm to the plant than good.
Constant Watering And Fertilization
Since pebbles have large spaces between them, it is easy for the water to pass from them. While drainage is excellent for most cacti, it means that you will need to water the plant more often.
Most cacti in soil need to be watered once a week. With a top dressing of pebbles, you might need to increase the frequency to two times a week.
Similarly, pebbles-infused soil may also have lower nutrients than regular cactus mix. So you might need to fertilize the plant more than usual as well.
Easier For Cactus To Die
When pebbles in the plant are too high, the cactus might die easily too. This is also true for cacti and other succulents that need less dry soil to grow.
Other than that, some cacti and other succulents need a lot of soil to grow properly. Topping these cacti with gravel might actually end up killing your cactus.
Therefore, you need to keep the pebble-to-soil ratio optimal in each cactus plant.
Pebbles vs. Crushed Stone For Cacti
There is not just one type of gravel you can use to top your cactus. Depending on the color and type of rock you prefer, you might have to choose between using small pebbles or crushed rock to top the soil of your cactus.
Pebbles and crushed stones are both useful top dressings for your cactus. While it ultimately comes down to being a matter of preference, the difference between pebbles and crushed stones is important to know.
Pebbles are rounded and uniform in shape. The spaces between them are uniform, and they drain water faster than crushed rock. Pebbles are not porous and therefore do not hold any water at all.
Crushed stones have jagged edges and are usually more porous than pebbles. Therefore, they can hold more water than pebbles.
Crushed stones can sometimes contain more nutrients than pebbles since they can hold more substances. The cactus’s roots can find better grounding in crushed rock than on rounded pebbles.
| Feature | Pebbles | Crushed Stone |
|---|---|---|
| Shape | Rounded and uniform | Jagged edges |
| Drainage | Drain water faster | Slower drainage due to porosity |
| Porosity | Non-porous, do not hold water | Porous, can hold more water |
| Nutrient Retention | Do not hold nutrients | Can contain more nutrients |
| Effect on Cactus Roots | Less grounding for roots | Better grounding for roots |
| Uniformity of Spaces | Uniform spaces between pebbles | Irregular spaces |
How Do We Add Pebbles On Top Of Cacti?
So, you have probably converted to using pebbles with your soil mix. Not only you can help your cacti grow healthily while also making your garden look phenomenal!
There are, however, some specifications you need to follow to ensure that the pebbles work well on the top of your cacti. Here are some of the steps you can follow:
Clean The Pebbles Well
It is always good to thoroughly wash the pebbles before adding them to the pot. This will ensure that no debris from their previous habitat or unfavorable bacteria and fungi are introduced into the new cactus plant.
To clean the pebbles, put them in a container, fill them up with water and add a few drops of dish soap. Rinse the pebbles thoroughly under the water, making sure that the water is nice and soapy.
Drain the water from the container and leave the pebbles out to dry. You can add them to the pot as soon as they have finished drying for at least a day.
Line The Bottom Of The Plant As Well
Topping the plant with small pebbles is a great idea. However, you should also look into lining the pot’s base with pebbles. It will make water drainage even easier in the soil and will help the cactus be sufficiently watered.
Keep Topping Up The Soil
Once every few weeks, you will need to top up the plant with more soil. This will ensure that the cactus has enough soil to get its nutrients from at all times. Make sure that the roots of the cactus are covered in soil entirely.
Use Fertilizer
Soil with pebbles also needs more fertilizer than regular soil. Make sure you don’t skimp on fertilizer, introduce some to the mix at least once in two months.
Additionally, you also want to ensure that you are not adding too much fertilizer to the mix since over-fertilization can easily kill or damage your cactus.
Mist The Cactus
Since the soil and the pebbles will be dry, you will want to mist the cactus occasionally. The mist will help keep the surface of the cactus cool, prevent it from being scorched, and keep it clean from dust and small bugs.
Conclusion
In conclusion, yes, you can. Pebbles, or pumice, are naturally occurring volcanic rocks that are lightweight, porous, and surprisingly absorbent.
They are highly valuable and often used to raise pH levels in the soil. Pebbles are an excellent choice for cacti since they absorb moisture very quickly and can help your cactus grow quickly.
Adding pebbles on top of your soil mix for a cactus is a wonderful idea. It keeps most succulents healthy and also adds aesthetic value to your garden.
Choose the right kind of pebbles and follow the steps for successful planting, and you will be on your way to being the best cactus parent!
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