How to Grow Cactus From Seed [Harvesting, Planting & Potting]

how to grow cactus from seed

Cacti are quite easy to grow from seed and the results can be very rewarding. You can purchase packets of mixed seeds which means you’ll never know what you’re going to end up with.

Preferably, you should grow your cacti inside in a controlled environment. But you’ll need some patience as some species can take several months to germinate.

Let’s explore how to grow cactus from seed in more detail.

Growing Cactus From Seeds.. Successfully!

What You’ll Need:

Here’s a list of the supplies to gather before you’re ready to sow your seeds.

  1. Cacti seed
  2. Small pots. These can be either plastic or terracotta.
Pro Tip
If re-using pots, make sure you clean and sterilize them. You can easily wash them in bleach and water and then rinse well.
  1. Potting mix that is free-draining. You can even purchase cactus mix from your local garden center.
Pro Tip
If you’re making your own mix, you might want to sterilize it either in the oven or microwave to protect your seedlings from bacteria.
  1. Vermiculite or perlite
  2. Cloche, plant dome or plastic bag

How To Harvest Your Own Seeds

Harvesting your own seeds is quite simple. You just need to ensure that you handle the seed pods carefully as they may be covered in spines. Here’s what to do.

  • Remove the pods or fruit from the cactus after the flowers have dropped off and before they dry out. They should come off easily. If not, they may not be ‘ripe’ and need a little longer.
  • Use a sharp knife to slice into the pods to expose the seeds within. Remove the seeds by scraping them out from inside the pod. These seeds are now ready to plant.

Planting Your Seeds

Planting your cactus seeds is easy and not very time-consuming if you follow these steps.

  1. Choose your seeds. You can purchase seeds from a retailer or harvest your own from cacti in your garden.
  2. Fill your chosen pots with the free-draining mix and gently firm down. Water well and wait for the excess to drain out.
  3. Scatter your seeds over the surface of the mix. Make sure that you don’t sow them too thickly so there’s enough space for the emerging seedlings to grow.
  4. Sprinkle a fine layer of vermiculite or perlite over the seeds to cover them but not too thickly. Cacti seeds don’t have a lot of stored energy so their shoots need to reach the surface quickly before it runs out.
  5. Put a cloche, plant dome or plastic bag over the pot to produce a humid, temperature-controlled environment.
  6. Place the pots on a warm windowsill or in a greenhouse, if you have one.
  7. Keep an eye on the pots and spray the surface with water to keep the mix moist.
Pro Tip
If your house is not warm enough, you can purchase a heat mat to place under the pots. This will aid germination of the seeds. Most cacti seed need a temperature of between 70 and 90 degrees Fahrenheit to germinate successfully.
  1. Once the seedlings have grown, you can remove the cloche, plant dome or plastic bag.
  2. Now you only need to water the pots when the mix becomes dry.
  3. Monitor your seedlings to make sure that they’re not getting burned with too much sunlight. They do need plenty of light but heat is more important.

How To Pot Up Your Seedlings

This part needs to be done carefully to avoid getting any of the spines in your fingers. Remember that cacti are extremely slow growers so it might be a year or more before you actually have to pot them up.

Here’s what to do:

  1. Use a fork or spoon to lift out the individual cacti plants. Remember to do this gently so that you don’t damage the tiny plants.
  2. Fill a small pot with your cactus growing mix about two-thirds of the way to the top.
  3. Gently place your seedling onto the mix. You can use a pair of tweezers to position it so that it sits straight.
  4. Add some more mix to fill in around the seedling.
  5. Water your seedling.
  6. Add some gravel to the surface of the mix. You can use a small spoon for this.
  7. Pop your potted-up cacti into a warm sunny spot. A bright window sill is ideal. Avoid direct sunlight though as your tiny plant needs time to recover from the trauma of being re-potted. Give it a month or two before exposing it to direct sunlight.

Frequently Asked Questions:

How long does it take for a cactus to grow from a seed?

As is the case with most succulents, cactus seeds can take anywhere from a few weeks to a few months to germinate.

Do cactus seeds need light to germinate?

Some cactus seeds do need light to germinate which is why they should be sown on or near the surface of the soil.

Should you soak cactus seeds to germinate them?

No, cactus seeds do not need to be soaked to aid germination as long as you keep the growing medium moist.

Do cacti need to be fertilized?

Because they grow so slowly, cacti don’t require a lot of fertilizer. However, you can give them a boost in spring and summer with a diluted solution of liquid fertilizer once a month.

Final Thoughts

Growing cacti from seed can be both fun and rewarding. If you have the patience to wait for the seeds to germinate, you’ll be delighted with the number of new seedlings you end up with.

The most important points to remember are to have a well-draining mix, to keep your pots in a humid environment and to not plant your seeds too deeply.

So, whether you harvest your own seeds or buy a packet or two from your local garden center, follow our instructions and you’ll have lots of tiny cactus plants to enjoy.

Have you grown cacti successfully from seed? Please share your stories with us in the comments below.

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