So you’re thinking about growing a cactus from seeds, eh? Well I have done this several times and while at first, it was a bit daunting, it is actually fairly easy as long as you give them the best conditions for germination. Here’s how to grow cactus from seeds.
First things first is the type of seeds to use. You can get a variety on the web, but you have to be vigilant and make sure it’s a reputable seller. Sometimes you can get random seeds, othertimes you may get an invasive species. The best place to get your cactus seeds are at a local garden store. They usually have a ‘mix cactus’ packet of seeds that will give you several different varieties.
If you’re looking for a specific type of cactus or succulent, I have had great success with UnusualSeeds.net. They are based in Europe so it does take a little while for the seeds to get to North America, but I have had really great cacti that started from their seeds.
Cacti (and most succulents) are not used to a lot of water. If you think about it – they usually grow in really hot, dry areas that rarely see rain. So it’s important to try to replicate that when growing cacti from seeds. The soil cannot hold a ton of water otherwise your cactus will root will rot.
Here’s what I usually use to grow cacti:
- Cactus mix
- Perlite or Vermiculite
- Coarse sand
If you’re thinking – which one works the best? Well, I hate to break it to you, I use all THREE together. That gives the best drainage, allowing the water to move through without the dirt being sopping wet.
Usually I use a 1/2/1 mixture. 1 part cactus mix, 2 parts perlite or vermiculite and 1 part coarse sand.
Once I mix these all together, I make sure it’s in a microwavable safe dish and cook for around 3 minutes. This ensures that any bacteria has been killed and the soil is sterile and is the best environment to grow cactus from seeds.
The best pot you can grow these in are nursery pots with plastic clear covers. These will allow the water to drain while keeping in moisture above the soil. See picture below:
There are two things you need when germinating cactus seeds. 1. Light 2. Warmth.
I usually will place the nursery tray in a very bright window in late spring that gets a lot of sun. I’ll then cover the tray with a piece of white paper or light cloth. That will allow the light and heat to flow through the tray without it being overpowering.
If you don’t have a window with a lot of light, a heat mat and grow light are a great replacement for actual sun and warmth.
HOW TO SOW THE SEEDS
Before you do any potting, place several seeds into a glass of warm water and leave to soak for about 1-2 hours. This will prep the seeds for germination. This isn’t totally necessary but you may find it takes longer to germinate when you don’t soak them.
As stated above, a sterile soil mixture is the best mix to grow a cactus – so make sure the cactus mix, perlite and sand are incorporated and microwaved for 3 minutes to ensure it’s sterile.
Fill each pod of the nursery tray with the soil mixture and give it a good watering. Allowing all the extra water to flow through.
Once the seeds have been soaking for 1-2 hours, gently place them into the nursery pods. I usually do 1-2 seeds per pod.
Spray with a little extra water – do not flood or the seeds may sink and get lost.
Cover with the plastic clear cover (or if you don’t have one, you can use seran/cling wrap).
Place in an area that has a lot of warmth and light. If the sun is shining directly onto the tray, place a piece of white paper towel or paper over the tray lid to dilute the light.
Do not water for at least a week.
If you are using fresh seeds – they should begin to germinate with 1-3 days.
Older seeds may take up to a month or so to germinate (or may not at all).
I will usually keep the plastic cover on for about a month or so before I begin to slowly remove it day-by-day. If it’s colder weather or winter, I will keep it on all winter.
There are a few common problems I have had when germinating cactus seeds.
- Red/Orange seedlings – this means the seedling is getting too much light and is getting sunburnt. This won’t kill the seed but you may want to move it into an area with slightly less sun (or dilute the light with a white piece of paper)
- The bottom of the cactus seedling turns brown – this usually means it has been given too much water an the roots are rotting. A seedling will not usually survive this – but you can attempt to take the seedling roots out of the dirt to air them out.
Once I remove the plastic lid and the cactus is in open air – water only when the soil is dry. This could be once a week or once every two weeks, but it is important to let it dry out before you continue watering.
When fall comes around begin to water less and less, allowing the cactus to enter a dormant phase for winter. I’d say probably water once or twice throughout the winter period.
I hope everyone enjoys this article on how to grow cactus from seeds. Please leave any questions below!