Can You Grow Cactus from a Seed? A Helpful Guide

How Long Does it Take for a Cactus Seed to Germinate?

The time it takes for a seed to germinate depends upon the species and where you are located. If you grow your cacti inside, they are likely to germinate quickly. This is because the indoor environment is more controlled. In this environment, germination can take three months or more.

If you decide you want to grow your seeds outdoors, they may take a few years to germinate. In the outdoor environment, cacti have to wait for the ideal temperatures and moisture content for them to grow. Indoors, you control those factors.

When working with cactus seedlings, you must understand they need proper protection and care. They need to be protected from the sun for a few years, until they are approximately 3” long. You can begin to introduce them to the sun when they are approximately 1” long. 

Start slowly and carefully introduce the sunlight. If they start to scorch, keep them out of the light. After some time, if you start feeling comfortable, you can leave them on the windowsill and if you want, start introducing them to the outdoors. 

Why Start with Seeds? 

You might be wondering why you should start with seeds instead of propagating from cuttings. There are several reasons why you might want to do this. We will list those below:

• Seeds only cost a few cents each 
• You can collect them from your other plants or obtain them from a friend 
• It’s easier to find species that may not be available as plants
• You can easily give seeds to friends as gifts 

Steps of Growing Cacti from Seed 

There are seven steps to growing cacti from seeds. We will discuss these below: 

Acquire Seeds 

Before you can plant seeds, you have to acquire them. You can buy cactus seeds at most garden supply stores. If you are unable to find them in your area, you can buy them online. The good thing about buying online is you choose your preferred species and they’re delivered right to your doorstep. Another option would be to pick the seeds from your already blooming cacti. You can find the seed pods in brightly colored offshoots that bear flowers. When the flowers fall off, the pod is left behind.

The best time to plant is late winter or early spring because it gives the seeds time to grow during the summer.

Harvesting from Pods 

If you decide that you want to harvest the seeds, you’ll need to remove the pods. The pods should be removed from the plant when they are damp but not wet. You will find the seeds inside the pod.

After removing the pods from your cactus, you will need to remove the seeds from the pods. Slice pods open with a knife and scrape off the seeds. Keep in mind the color and the size of the seeds will vary based on the species. 

Soil is Important

Cactus seedlings are not very tolerant to a soil that does not drain well. You will need to protect them from potential issues such as mold and bacteria. This means your soil needs to be sterile. There are several ways that you can sterilize your soil: 

Steam 

Soil can be steamed in a pressure cooker. Simply pour a few cups of water in the cooker and place shallow pans of soil over the rack top. Cover each pan with foil and close the lid. Steam for about 30 minutes. Leave the pan wrapped with foil until you are ready to use it. 

Microwave 

Another way to sterilize soil is to place it in a microwave. Fill containers with moist soil and cover with a lid, making sure there are vent holes so pressure doesn’t build up. Heat soil for 90 seconds. Then, tape the vent holes closed and allow the soil to cool. 

Oven 

Place soil in an oven-safe container and cover with foil. Place a thermometer at the center and heat at 180°F for approximately 30 minutes. Allow soil to cool and only remove foil when you’re ready to use it. 

Choose the Ideal Soil Mixture 

In addition to making sure your soil is sterile, you need to make sure that you’re using the appropriate soil mixture. You will need the following to ensure that your seedlings germinate: 

• Pumice/granite stone 
• Vermiculite 
• Cactus soil 
• Perlite 

The base should be pumice/granite stone and cactus soil. Be sure to sift the cactus soil to remove chunks because they could cause drainage issues and may provide a place for bacteria to breed. After the soil is sifted, mix with pumice/granite stone. Limestone screenings will also work. 

Pour the mix into the containers where you are going to plant your seeds, but don’t pack it in. Allow it to remain natural-looking. Since seedlings are small, a 2” pot will be fine. If you are recycling old pots, be sure to clean them with bleach water and rinse thoroughly. 

Since the seeds need high-drainage soil, test it by moistening it and making sure it drains completely. 

Spread seeds on top of soil. Resist the urge to pack them in. Then, cover with a thin layer of cactus soil or sand. You do not want to bury them deep because they only have a little bit of energy and may not sprout if they’re too deep. 

When spreading seeds, if you are planting more than one kind of cacti, make sure to label the containers. Since they may have different growing requirements, you do not want to end up getting confused and giving them the wrong care. 

Check out our Ultimate Cactus Soil Guide here!

Expose Seeds to Sun 

After moistening the soil and covering the seeds with sand, you need to place a transparent lid or plastic wrap over the container. Then, place the seeds in an area where they will have access to adequate light. A sunny windowsill might be a good option. 

At this point, they should not be placed outside because intense sunlight could be harmful. The purpose of the lid is to hold the moisture in while also allowing light to reach them, which helps them to sprout. 

Keep a close eye on your seedlings. If they start turning red or purple, they are most likely getting sunburned. Decrease the amount of light they are getting.

During the initial stages, heat is needed more than light. Ideally, you should place them in warm areas of your home, such as the kitchen. However, a heating mat placed under the containers is a great way to improve germination. 

In order for most species to germinate, cacti need a temperature of 70°F to 90°F.

What to do When Germination Begins 

As mentioned previously, cacti are slow growers which means that you must have the patience to see them through the process. After you plant the seeds and provide them with the right light and temperature, they will eventually begin to germinate. It’s not going to happen right away; it could take a month or so. 

At this stage, tiny spines will begin to form. You should now take away the lid or plastic wrap and let it breathe. However, don’t do it all at once. Take it off for a few hours each day, gradually increasing the amount of time until the cacti no longer need to be covered. 

Watering the Seedlings

Of course, uncovering the cactus means that the water is going to evaporate quicker, so you’ll need to have a watering schedule in mind to keep it from drying out and dying. 

Ideally, you should be using fresh or distilled water to prevent algae and bacteria from growing. If your tap water tastes like chlorine, do not use it on your cacti. After all, the newly formed roots are still tender, so chlorine will burn them, which can kill the plant. 

Even as your seedlings begin sprouting and are doing well, the roots are still young and can’t absorb nutrients very well. Keep the seedlings wrapped until they start to grow. The humidity facilitates water and nutrient absorption until the roots are strong. 

There are some cacti species that don’t have spines, so the only indication of growth you’ll have is when the seedlings sprout. Don’t leave water on the soil and keep an eye on the plant for signs of too much water. You should never leave standing water in the container. The best way to test the moisture in the soil is to dip your finger into it. 

Once the seeds have germinated, stay on the same timetable you established when you started watering. Pay attention to signs of health or lack thereof such as thinning, algae on the soil, and fungal infections. 

Repotting 

Once your seeds have overgrown, it’s time to transplant them. You need a container that will drain quickly, so be careful when you choose. The container should contain drainage holes so that the excess water will drain out to avoid root rot. 

Some examples of planters with good drainage are unglazed ceramic and terracotta, but there are other containers that will work if you don’t have these. The goal is to find one that drains quickly, keeping the soil moist but not soaked. 

Of course, getting the proper container is only part of the story. You also need to be careful with how much water you’re giving your cactus. 

Again, cacti can grow slowly, so it may be a year before it’s even the size of a marble. You need to make sure it has plenty of room to grow. If you put it in a small pot, you keep it from reaching its growth potential. 

When transplanting your cacti, use the same mixture you used to create the original potting mixture. Place the plant in the container and then pour the soil mixture on top. Then, water every 3 to 4 days and don’t cover the plant with plastic wrap or a lid. 

Recovery time after Transplanting

Once you have transplanted your cacti into new pots, you must give the plants time to adjust. This will help it avoid any issues. The plants need time to recover since transplanting can be so stressful. If you had the plant in an area with ample sunlight, consider keeping it in a shady area for a few days and slowly reintroduce it back to the sunlight until it can tolerate full heat. 

Since cactus plants are succulents, and store water, they have very low requirements when it comes to water. As a general rule, you should wait until the soil is dry before watering the plant. 

Once the plant is growing, you can water once a month. The water requirement is especially low during the winter, so you should only water when the plant absolutely needs it. It’s better that cacti are under watered than overwatered because it’s easier to deal with lack of water than excess water. 

During the months when the plants are growing, you should use a fertilizer to help- but keep in mind, cacti don’t need as much fertilizer as most other plants. 

Frequently Asked Questions 

There are a few questions that people often ask when it comes to growing cacti from seed. Those questions are as follows: 

Can you get cactus seeds to germinate faster? 

Generally, cacti grow very slowly- sometimes it can take years to grow. However, it is possible to encourage them to germinate faster. Before planting, soak seeds in warm water for approximately 30 minutes. This loosens up the seed coat and activates germination.

How does a cactus plant produce seeds? 

In order to produce seeds, the flowers of a cactus must undergo pollination. This is the process of pollen being transferred by insects/birds from one plant to another. Once the pollination has occurred, fruits develop. These fruits contain the seeds. One cactus plant has the ability to create a million seeds.

Conclusion 

As you can see, it’s really not all that difficult to grow your cacti garden from seeds. This guide should be helpful in getting you started. Make sure to keep all of these things in mind and you’ll be well on your way!