There are different things to remember when learning how to grow a cactus from seed. Although propagation through cuttings is a favorite of many owners, growing cacti from seeds is definitely a possibility and well worth exploring. The basic steps are the following:
- Pick the seeds by either buying them or by taking them from a cactus itself.
- Plant the seeds in an appropriate soil mix. Sterilizing the soil is usually a good idea.
- Keep this soil moist throughout the process.
- Cover with a plastic bag to create a greenhouse effect.
- Keep this in a well-lit place but not under extreme direct sunlight.
- Maintain a steady temperature. Use a heating pad if necessary.
- Once seeds are germinated, open the plastic lid to let the plants breathe.
- Repot the plants if needed.
Although we have described the basic process, let’s find out more about growing cacti from seed and how this method compares to others.
How to Grow a Cactus From Seed
Materials and Provisions
There are some basic materials that can help in the process. These may include the following:
Evidently, the first and most important material will be the seeds themselves. We can either buy them, trade them or pick them from cactus plants themselves.
Pots will evidently come in handy. Depending on the method you choose (for instance, soaking the seeds or not), pots will vary. Small plastic pots will generally be useful.
Soil mix is, as usual, vital. We’ll generally want to be using something like free-draining compost or a traditional cactus compost mix.
Fork, Spoon, Tweezers
An assortment of instruments will be important when handling our plants.
As we’ll find out throughout this article, plastic bags can come in handy. They’re used to retain moisture when growing seeds in pots. Moreover, sealed bags will keep out undesirable pests away from our fledgling seedlings.
Sunlight is extremely important when learning how to grow a cactus from seed. This can be a challenge. Some owners use artificial lighting to achieve a more constant provision of light.
There are some basic steps to consider when learning how to grow a cactus from seed:
First of all, we must fill a pot with good free-draining compost. It should be moist. We want to make the surface firm and level. Then, we must scatter the seeds over the surface.
Now we must sprinkle a thin layer of something like vermiculite or grit over the seeds. We must strive to cover the whole surface of the compost that we used. Now, we want to leave the pot inside a greenhouse.
If a greenhouse is not available, then we can leave the pot on a windowsill with good warmth and provision of sunlight. It’s usually a good idea to also cover the pot with a plastic bag and so preserve the moisture.
Now we wait. The seedlings will develop after some weeks. This will vary depending on the type of cactus we are dealing with. It’s important to remember that we need to keep the soil moist. Whenever it dries, we must remove the plastic bag and water again.
Eventually, usually by the following spring, seedlings should be ready to be transplanted. To do this, we can use a fork or spoon and slowly and carefully remove each cactus.
To find homes for these little cacti we must partly fill up a small pot and ease the little cactus inside.
Now we must fill the area around the seedling with more compost. We must also keep our plant in a sunlit place, like a windowsill.
Conditions and Requirements
Weather and Temperature
When we talk about how to grow a cactus from seed, the temperature is important. We must take into account that all cacti are different. Particularly when it comes to growing cacti from seeds, temperature needs may vary depending on the specific seeds. Having said that, however, the most typical temperature will be around 70ºF-90ºF (21ºC-32ºC).
There are some species that require a bit more warmth. Ferocactus seeds, for example, require a bit more heat. Some owners who try to grow this cactus or others like it use a heating pad beneath it.
Position and Placement
Growing cacti from seeds should be done indoors. That’s the only way in which we can control temperature and keep our growing seeds protected from the elements. This way we can grow cacti from seeds throughout the year. Note that if we need to keep light provision steady we may need to set up artificial lights.
Watering and Humidity
When growing cacti from seeds, we want to keep the soil moist all the time. This is quite unusual, because, as we know, full-grown cacti prefer dry conditions and a ‘soak and dry’ method of watering.
Note also that by covering the growing seeds with a lid or plastic covering, we’ll create a sort of greenhouse effect. This will keep moist and even humid conditions which will allow our seeds to prosper.
It’s possible to fertilize young seedlings during the growing season. A typical cactus fertilizer or houseplant fertilizer at about ½ strength will do.
Many owners like to sterilize the soil that they use when attempting to grow cacti from seeds. Note that most commercial soil is usually pasteurized and some is sterilized. Check the labels. Apart from that, it’s ideal that we use a good potting mix which has about ½ of the granite, perlite or pumice for proper drainage.
Growing via Seed vs. Growing via Cuttings
Why should we grow cacti from seeds at all? Isn’t it better to propagate the cactus via cuttings? Let’s examine this issue more closely and discuss the advantages and disadvantages of each method.
Propagating cacti with cuttings is relatively simple. In fact, we could say that this is the most common and easiest route to create more cacti. Stem cuttings are basically taken from an existing plant. They’re then allowed to dry and they eventually start taking root again.
We need to disinfect the tools that we’re going to use. To do this, we can use warm water and soap or rubbing alcohol or alcohol wipes. Note that we want to disinfect the tools every time we make a cut. This avoids introducing any sort of unwanted pest or fungus into our plant. A sharp knife or a razor blade will usually be enough. It’s ideal that we achieve a very clean cut, avoiding rough or jagged edges.
Then. we simply need to grab the cactus and make a cut with a knife. Now, what we want to do is let this cutting dry. After a few days, the wound will somewhat heal and a certain callous will form over it. It’s best to try to leave this cutting away from direct sunlight while it dries.
Many owners like to dip this cutting into rooting hormone. Now we need to plant the cutting. To achieve this, it’s necessary to prepare an adequate soil mix with proper drainage. We must plant the cutting securely and let it rest. It’s important to water sparingly at the start. Once the roots are established, we can start applying a ‘soak and dry’ method.
The biggest advantage is the sheer simplicity of the process of propagation via cuttings. It’s a very simple method which can provide relatively fast results.
It’s also true that this method is usually a bit more robust, so to speak. When we discuss how to grow a cactus from seed, we must concede that there’s a certain fragility to the process, at least until we get some germination.
There are obviously disadvantages to propagating via cuttings. It’s best not to propagate during heatwaves. Also, plants which are stressed or struggling to survive are not ideal for propagation.
There’s also the problem of the dormant phase of cacti. This is a phase when plants shut down and don’t grow. Propagating during this time is not ideal and will probably not give good results. Moreover, propagating during these times makes the plant quite susceptible to disease and even rot.
Now then, let’s examine the pros and cons of growing cacti from seeds. First, seeds are a cheap option. They can be bought cheap or, even better, collected from an existing cactus. It’s also simple to receive seeds from fellow owners and friends.
Another great benefit is that sometimes there are seeds available for certain cacti, which would otherwise be hard to find to propagate through cutting.
Finally, an added benefit for certain owners and enthusiasts is that when they use seeds, they’re able to observe the whole life-cycle of the plants. This can be a lesson in itself.
The most obvious disadvantage is time. Growing cacti from seeds takes a lot more time than propagating cacti via cuttings. It can take years before a cactus grows from a seed and reaches a blooming size, where we can see flowers.
Another problem when we talk about how to grow a cactus from seed is that seedlings are a bit more fragile than cuttings. Propagating via cuttings may be a more robust method that gives more predictable results.
It’s important to note that there are other methods, most related to cuttings than seeding. Some cacti, though not all, are able to propagate via lateral shoots or offsets. These offshoots can be removed and placed into soil mix.
Another interesting method to propagate cacti is through grafting. The process of grafting is essentially taking a piece of a cactus and attaching it onto another cactus. Owners usually call this grafted part the ‘scion’. The base is usually called the ‘rootstock’.
Frequently Asked Questions
How do you germinate cactus seeds?
First of all, we want to place the cactus in a bright place, where there isn’t direct sunlight. It’s also important to note that cacti prefer dry environments. This is true, but in the case of germination, we want to make an exception and keep the soil moist (though not soggy).
Eventually, after a few weeks or months, the seeds will sprout. Remember that we want to maintain a level of moisture, which will help the germination.
How long does it take to grow cactus from seed?
In principle, anything that produces a seed should be able to be reproduced from seeds. This is a bit more complicated in the case of cacti though. Seeds which drop in their natural environment may very well take years to actually germinate.
When dealing with how to grow a cactus from seed in a controlled environment, we may achieve better results. We may have germination in a matter of months, depending on the type of cactus and the conditions we create for it.
Are cacti easy to grow from seed?
That depends on the cactus. Some seeds take more work than others. In general, though, it’s quite possible to grow cacti from seeds and owners shouldn’t be intimidated by the process.
How does a cactus produce seeds?
Seeds form in blooms. The best way to take them is to remove the flowers as they are drying off and store them in a paper bag. Evidently, another way to acquire seeds is by simply buying them online.
Should I soak cactus seeds?
Sometimes we may need to remove dormancy to make sprouting possible. To achieve this, some owners soak seeds. There are some particular types of seeds which benefit from this approach. Opuntia, for instance, has a seed which is very tough. Soaking such a seed will generally be beneficial towards achieving germination.
First, we want to scarify the seed by making a small opening using a small knife. Then, we want to let the seed soak in lukewarm water for a few days. Then, we want to place this in soil and in the freezer or outdoors for about 4 to 6 weeks. After this process is done, we want to plant the seeds into a moist, well-draining mix.
Can I germinate seeds with paper towel?
Paper towel germination is an alternative that some cactus owners prefer. This method has certain advantages. By using this method we can control the moisture content and we can also observe the seeds to see when they germinate. Some steps to remember when we are using this method, are the following:
- Tear a paper towel. Moisten one half and leave the other half dry.
- Now place about four or five seeds on the moist half and cover it with the other half of paper.
- Now place these papers inside a resealable bag.
- Set this bag out of direct sunlight. Room temperature will be just fine. The idea is that this bag will act as a sort of greenhouse, retaining heat and moisture.
- After the seeds have sprouted they must be transplanted manually to the soil mix and pot which we’ll use.
What do cactus seeds look like?
Cactus seeds will vary in appearance. Some of them are black or red. Others will be extremely small, no larger than a grain of sand.
What is sterilization of soil?
When we learn how to grow a cactus from seed it’s important to remember that cacti seedlings are actually quite fragile. Many owners like to sterilize the soil they use. They’ll put the soil in the microwave, for instance, for about 4-6 minutes. Other people prefer to quite literally bake the soil in a regular oven. This process basically kills potential threats to seedlings. Note that some commercial soil mixes may already be sterilized. Check the label to be sure.