Growing cactus from seeds

While adult cactus can take burning sun and drought conditions, their seedlings need careful pampering! Source: cliparting.com

Most cacti come from arid climates and our image of a cactus is precisely that of a plant adapted to growing in harsh conditions: a swollen stem that holds water, no leaves in order to reduce moisture loss, abundant spines to protect its valuable assets, etc. You might imagine therefore that you need to sow cactus seeds in sand and under conditions of burning sun and great aridity… but you’d be wrong.

In fact, in nature, not even one desert cactus seed in 100 germinates … and not even one seedling in 1,000 reaches maturity. Most years, there is no germination at all! The seeds can lie dormant for years if necessary, waiting for Mother Nature’s sign that it’s time to start growing: a good, thorough rain. And yes, it does rain in a desert … occasionally. Only then, when the soil is moist, do the seeds, often decades old, finally germinate. Seedlings then struggle to grow as quickly as possible, a real battle against the elements, but if the soil dries them out too quickly, they die. But from time to time, there’ll be a year when the soil remains moister than normal or when there are repeated rains. It’s under those conditions that the next generation of cacti really manages to get a good start.

So, unless you want to have success with only one cactus seed out of 1,000, don’t treat cactus seeds like desert plants. Instead, coddle them! Sow and treat them like any other plant. Here’s how:

Seedlings Under Cover

Sow cactus seed under high humidity, just like you would tomato seeds or marigold seeds. Source: living-rocks.blogspot.ca

Sow in a small pot moistening the seed mix thoroughly and simply press the seeds into the soil. Cover with a dome or a transparent plastic bag to maintain high humidity. (I know: that sounds illogical for a cactus, but trust me, it works!) And place the pot in a warm, well-lit spot (light is necessary for germination), but away from direct sunlight, otherwise the poor seedlings will get too hot inside their clear plastic shelter. A location under a grow light is perfect. Germination can take from several days to several weeks.

Those chubby points are cactus seedlings. Notice the pair of cotyledons. Source: www.reddit.com

Curiously, even though most cacti have no leaves as adults, they will as seedlings. Each chubby seeding bears 2 cotyledons, just like any other dicot plant, only much thicker. At the junction of the two cotyledons a bit of spiky growth will soon appear: the stem of the baby cactus.

As long the seedlings are under plastic, no watering should be necessary, although if the soil surface does dry out, you could lightly spray the growing mix with water. After 2–3 months of growth, gradually remove the plastic bag or dome, opening or lifting it a bit more each day until the seedlings harden off.

Once the seedlings are acclimatized to normal indoor conditions, it’s time to consider transplanting each baby to its own individual pot. Source: www.worldseedsupply.com

Once the seedlings have acclimatized to indoor conditions, transplant each into its own small pot. This time, use a cactus potting soil. Start watering them like a typical houseplant (not quite like a desert cactus at this point), that is, when the soil is dry to the touch. Moderate lighting is also still the best choice at this stage.

It is only about a year after the seedlings have been growing on their own that you should begin treating them “like cactus,” placing them in full sun and letting the soil dry out thoroughly before watering again. Cacti are fairly slow growers, but some will be quite presentable by their second year. How long before they bloom? Mammillarias or rebutias may reach blooming size in as little as 2 to 3 years, but most small cacti are 5 or 6 years away from blooming. As for candelabra and barrel types, figure 15 to 50 years… if indeed they ever bloom.

Exceptions

Obviously, there are exceptions to the sowing recommendations made above. Several opuntias from northern areas, for example, will require an extensive cold treatment before germinating, but otherwise, the process described above will work well with almost any desert cactus.

Succulents Too!

Although the information above was written with cactus in mind, most other succulents also need coddling when they first germinate. Whether it be agaves, aloes, euphorbias or crassulas, when you sow them, give them high humidity and only moderate light until they’re well established. In other words, baby them at first. They’ll love you for it!

Cactus Seeds Galore

Packs of mixed cactus seeds are available in most garden centers.

You’ll probably find packets of mixed cactus or cactus and succulent seed in your local garden center and most of the larger seed catalogs (Stokes Seeds, Park Seed, Halifax Seeds, Chiltern Seeds, etc.) also offer them. For a more extensive selection of cactus seeds, ideal for the cactophile, try Cactus Store or Mesa Garden (USA), RarExoticSeeds (Canada) or Kakteen (Europe).

Raising Cactus From Seed

Introduction
Growing cactus from seed is not terribly difficult, although it does take purpose and patience. Any attempts to grow cactus from seed haphazardly will seldom result in mature plants. And so it is in nature. Many thousands of seeds are produced for every one plant that reaches maturity. Fortunately, we can improve those odds substantially by following a few tried and true methods. This article is intended as a general overview of seed propagation and I do not claim that the method described herein is the only way to do this nor do I claim it is superior to other methods. Rather, this is just one method that has produced positive results. It is my goal to encourage other cactus enthusiasts try their own hand at seed raising. I, myself, have learned the methods described below from more seasoned growers after failing miserably doing it on my own. I still don’t consider myself an expert on the subject and on that note you should not be discouraged if you don’t get it right the first time.

Why Seeds?
It is well known that many cactus plants can be propagated easily from offsets or cuttings. Larger or full grown plants are also available at many nurseries or via mail order. So why grow cactus from seed?
Growing cactus from seed has several advantages… Here are a few of them:

  • Seeds are inexpensive – often only a few cents for a pack or free if you collect them from your own plants
  • You have lots of plants to trade or give away to friends
  • You can get species and varieties not available as plants
  • You get more variation than with cuttings – and you get first pick of the plants too
  • You can see the whole life-cycle of your plant
  • Seeds can be mailed much easier than plants

Recognizing these benefits, there are also some disadvantages, the biggest of these being time. If you want to see flowers on a given plant, it may take many years to reach blooming size from seed in some species. Even those that flower early, will take at least a year before blooming. Others will bloom in around 3 years or so. It is also generally true that seedlings are harder to keep alive than adult plants. Very often seedlings cannot handle the same temperature variations, light intensities, pest attacks, or other challenges that mature cactus plants can easily survive.
So you must consider these pros and cons, but remember that many others have done this already. By reading articles like this one and connecting with other growers, you can increase your chance of success considerably. If you do, I think you’ll agree that the pros outweigh the cons.

Seed Packs from the CactiForum Seed Depot

Getting Started
The first thing we need to sow seeds is some pots. Seedlings are very small and grow fairly slowly, so 2inch pots are sufficient. There seems to be an unwritten philosophy among seed growers that the cheaper the seed growing setup the better. This is not to skimp on meeting the needs of the seedlings, but to do utilize existing materials as much as possible. One of the ways to raise seeds on the cheap is to reuse pots.

Another way is to use leftover food containers or other similar items. In this case, I had a number of small plastic tubs that mealworms come in for feeding my reptiles. These containers did not have holes in the bottom, so I drilled some. As we will see later, the seedlings will be in 100% humidity and therefore drainage holes are useless. I added them because I wanted to be able to keep the seedlings growing in the same pot as long as possible to avoid early transplanting risks. If I were to transplant them immediately after moving them to an open air environment, then I would have skipped the holes.

When reusing pots, it is important to clean them to avoid potential fungus, algae, or other pests that may quickly kill delicate seedlings. Taking some precautions up front to prevent pests and disease is far easier than trying to fend off threats after germination. Cactus seedlings are especially sensitive when small and fungicides or insecticides can kill or weaken the cactus seedlings. Some people add a mild fungicide when sowing, but proper sterilization should eliminate the need for this. To clean the pots, I soaked them in bleach water for a good while and then rinsed them thoroughly

Next, we need to prepare some soil. I use my standard cactus soil mix and sift out the larger pieces. You can read about cactus soil mixes on this page. I found a child’s beach toy to be a perfect tool for this job. Of course, the soil must be dry in order to sift it. After the large parts are removed, I wet the soil so that it is damp throughout, but not soggy. Then the soil goes into the microwave for 4-6 minutes depending on how much soil there is. This is to sterilize the soil and kill any potential threats to the seedlings. It is best to stop partway through and mix the soil. Be careful as it can be very hot in parts and cool in others. Some people bake the soil in an oven for the same purpose.
Again, using your typical soil mix won’t work for every species, but should be fine on more common species. When you get into some of the more challenging species, your best bet is to seek out advice from other growers that have tried that same species. Some species are extremely slow and will be in the seedling environment for well past a year. Some species will not tolerate the same amount of organic material as others.

After the soil has cooled some, we are ready to fill our pots. It will cool even more as you do this. I use an empty pot as a scoop and fill the pots right to the top. Once filled, I tap the pot and smooth out the surface with my finger. This prevents the seeds from falling down any large gaps in the soil surface. Then I sprinkle the seeds evenly over the surface of the soil. In the picture below-right, I pointed out a couple of the seeds using red arrows. The green arrows are pointing to fertilizer. I like to use a time release fertilizer like Osomocote as it will slowly release as the seedlings grow. Note: This process can be a bit messy so I used a flat cardboard box as a work tray. When finished, I just dispose of the cardboard and clean-up is done.

Unless you are one of the few growers who don’t care about names, it is critical that you carefully label the pots as you go. Seeds and seedlings can look very similar for the first few years. Even at maturity, some species are a challenge to ID properly without knowing the origins of the seeds. Melocactus are one example in particular, but there are many others. There are several ways you can go about this and most people put a tag in the pot with the full plant name and collection number if applicable. In my case, I numbered the pots on four sides. Then I entered the names with the corresponding number in a spreadsheet on my computer. In this way, I can easily update it with notes as germination occurs or when I transplant them later on. Often people keep track of the number of seeds sewn and monitor the germination rate for each one. I didn’t do that this time, mostly because I forgot!
After the seeds are in place, I take some of my sifted soil pinched between my fingers and sprinkle it over the seedlings until they are just covered. It is not necessary for the seeds to be covered, but helps to support them once they start to grow. Each species is different and some need light to germinate so consult the CactiForum if you are unsure about this. At this point, I take a spray bottle and give the plants a good soaking. The soil is already damp from our pre-microwave wetting and now I saturate it until the water just drips out the bottom. Be careful to use only a light spray for this or you might wash the seeds right out of the pot.

For this article, I chose to use the “baggie method” which is a popular technique among growers worldwide. In this way, I place each pot of fresh-sown seeds in a ziplock baggie and seal it shut. This method has several benefits. It eliminates the need for watering as the moisture will condense inside the bag and soak back into the soil providing a constant moist environment for the seedlings. This kind of environment works best for most cactus seedlings despite the fact that it would quickly kill a mature cactus. A second benefit is that the sealed bag keeps out undesirables like fungus, gnats, or other pests. Even if you sterilize the soil and pots as we did earlier, if the pot is not sealed, many pests will find the warm/moist environment too good to pass up. And they will find the tender green cactus seedlings to feed on just an added bonus!
Seedlings will appreciate bright light, but will not do well in full sun. The sun is too strong for almost all seedlings and in the wild they usually start growing in the protection of a rock or other plant. With this caution in mind, placing the pots in a bright spot under a shelf in the greenhouse or in a window that gets sun for only part of the day is a good option. For even better control, however, artificial lighting is ideal. You can find more information on which lighting setup to use for seedlings at the end of the artificial lighting article. In my case, I used two lighting hoods that I already had for keeping reptiles with a compact florescent bulb in each one. For a propagator, I kept with cheap-seed-raising tradition and used a 10 gallon aquarium that I already had. I used a piece of stiff cardboard for a lid and cut holes in it for the light domes. Since the pots are in baggies, I do not have to worry about keeping the whole propagator humid or sealed up. Since the aquarium is clear glass, much of the light that should be going to the seedlings is escaping into the room. This was easily remedied by taping some white scrap paper around the outside of the tank to reflect the light back in.
I stuck a thermometer at one end and cut out the paper so that I could see it without opening the propagator. Most cactus seedlings like a temperature of 70F – 90F to germinate. This is a general statement, of course. Some species, such as Ferocactus may not germinate at the low end of that and you’ll have to turn up the heat. Many people use a heating pad on the bottom for controlling temperature. If you do, be sure that you use it in conjunction with a thermostat or it could overheat quickly.
Conclusion
Hopefully, in this brief article, I’ve been able to inspire you to give seed raising a try. As you see, there is a bit more effort required than just picking a cactus off the rack at a nursery. Some thought needs to go into the process along with taking the proper precautions. If at first you don’t succeed, adjust your methods and give it another try. Start with common species and get advice from other growers. Finally, if you’re on a tight budget, your frugal and innovative approach will be admired by even the most expert seed-sower.

Author: Daiv Freeman

Seed Germination Instructions

Lithops seeds germinated on pumice.

There are many ways to germinate seeds. Below are important steps you can follow to increase your success with germinating seeds of cactus and succulent species. Some species and seed types need special treatment. I have written down the most important exceptions. Feel free to mail me if you need any further help.

Basic steps for successful seed germination

  1. 1. Fill a container with good draining soil. We recommend 50% regular potting soil with 50% coarse sand, fine pumice or grit (1-3 mm). Remove any big chunks (peat) from the potting soil if needed. Divide the seeds on the soil.
  2. 2. Add a thin top layer of grit or coarse sand. If the seeds are extremely small (like Lithops) then do not apply a top layer. Thick seeds usually germinate better after a 24 hour soak in water.
  3. 3. Let the container soak up water (from beneath) for 5 minutes.
  4. 4. Let excess water drip away.
  5. 5. Put the container with seeds in a zip-lock bag or other transparent bag or box. Make sure humidity is high.
  6. 6. Most seeds germinate under light conditions at circa 24 °C.
  7. 7. Increase ventilation when most seedlings have appeared. Germination can take 1-4 weeks depending on species.
  8. 8. Never let your seedlings dry out. Keep watering the container from beneath to prevent damage from splashing water. Apply good ventilation to prevent infections with mold.

Cactus

Cactus seeds germinate fine using the above method. Thicker seeds from species like Opuntia can be soaked in water at room temperature for 24 hours prior to sowing.

Adansonia

These are thick seeds and need a 24 hour soak in water before sowing. Plant Adansonia seeds 1-2 cm deep in soil. Germination is erratic and can take 1-6 weeks. Sow in a deep tray to allow the taproots to grow downward.

Adenium and Pachypodium

Plant the seeds 1 cm deep in soil. Germination should be within 10 days at temperatures around 28 °C at very high humidity.

Dionaea, Drosera, Sarracenia

These carnivorous plant species germinate best on a mix of very moist peat and/or sphagnum with coarse sand. Do not cover the seeds. If they do not germinate within 3 weeks then place the entire seed tray in the refrigerator for 2 month to simulate winter time. Many of these species need a winter before they can sprout. Maintain a very high humidity. For detailed information on growing carnivorous plants from seed please check out these websites: GrowSundews.com and Carnivorousplants.org.

Lithops (and other Mesembs), Echeveria, Anacampseros, Sedum, Crassula

These species have tiny seeds which should not be covered with soil. They germinate best at 18-20 °C temperatures.

Palms

Usually thick seeds which need a 24-48 hour soak in warm water before sowing. Place the seeds in a zip-lock bag with some moist perlite, bims or cocos fibre. Keep at temperatures around 28 °C. Check the bags on a daily basis. Remove germinating seeds from the bags and plant in a deep container using a soil mixture of regular potting soil with 25% perlite or bims. Germination can be erratic and can take 1-6 months depending on species.

Strelitzia

Remove all the fluffy tufts from the seeds and then soak for 24 hours in warm water. Plant the seeds 1 cm deep in regular potting soil with 25% bims or perlite added. Germination can be erratic and can take 1-6 months.

Seed Starting Times: When To Start Seeds For Your Garden

Spring has sprung — or nearly — and it’s time to start your garden. But when to start seeds? The answer depends upon your zone. Zones are determined by the United States Department of Agriculture. They separate the zones according to temperature. It’s important to know the proper times for starting plants from seed. This will enhance germination and help ensure healthy vigorous plants. Keep reading for some seed starting tips.

Starting Plants from Seed

Some plants are best started indoors and grown for transplant and some can be sown directly outside. Most transplanted seeds grow faster and produce more quickly than those directly sown outside.

For the most part, the early fall crops are suited to direct sowing, while the summer crops or those requiring a long growing season should be sown indoors. Seed starting times need to take into consideration maturity, length of growth season, variety, zone, and time of last expected frost.

When to Start Seeds

As a general rule, seeds need to be started four to six weeks before the date of the last frost. Seed starting times are calculated by taking the date of the last frost and subtracting the days until transplant. The seed packet will tell you how many weeks.

The best time to start seeds is usually late March to late May. Only the southern zones are suitable for starting plants from seed in the earlier months. Give the plant enough time to germinate and grow to an appropriate transplant size.

Seed Starting Times for Different Seeds

The plants that should be started the earliest are broccoli, cabbage, cauliflower and head lettuce. Sow seeds for these indoors 10 weeks before the date of the last frost.

The warm season plants such as tomato, peppers and eggplant require seven weeks. The best time to start seeds such as cucurbits and melons is four weeks ahead of last frost.

Once your seeds have germinated and grown the appropriate amount of time, harden them off before full transplant. This means gradually acclimating the new plants to outdoor conditions for longer and longer periods of time. This reduces shock and ensures healthier transplants.

How to Sow Seeds Indoors

Use a quality seed starter mix or compost. Any container that has good drainage is appropriate, but even just a flat will work since seedlings need little root space.

Sow the seeds according to the planting depth recommended by the seed packet. Some seeds recommend just a dusting of soil over the seeds, while others need more submersion.

You can enhance germination by soaking larger seeds in water or wrapping them overnight in a damp paper towel. Put the containers in a warm location. Most seeds need temperatures around 60 F. (16 C.) for best germination.

Move the containers to a well lit area after they have germinated.

Vegetable Gardening Calendar

Enter your location in the field above to get customized planting dates.

EXAMPLE CHART

30% probability of frost free after May 15 (at JAFFREY MUNI AP, NH climate station).

Crop Based on Frost Dates Based on Moon Dates
Start Seeds Indoors Plant Seedlings
or Transplants
Start Seeds Outdoors
Beans May 22-Jun 12
Jun 3-12
Beets May 1-22
May 1- 3, May 19-22
Broccoli Apr 3-17
Apr 5-17
Apr 24-May 15
May 4-15
Brussels Sprouts Apr 3-17
Apr 5-17
Apr 17-May 8
Apr 17-19, May 4- 8

What is a Planting Calendar?

Find the best dates for planting vegetables and fruit in your garden! Our free planting calendar calculates the best time to start seeds indoors and outdoors, as well as when to plant young plants outside.

Simply put, a planting calendar is a guide that tells you the best time to start planting your garden. Most planting calendars are based on frost dates, which dictate when you should start seeds and when it’s safe to plant outdoors. Our planting calendar also shows dates for planting by the Moon (learn more about this technique below).

Frequently Asked Questions

Why Should You Start Seeds Indoors?

Starting seeds indoors gives your crops a head start on the growing season and the chance to grow in a stable, controlled environment. Outdoors, the unpredictability of rain, drought, low and high temperatures, sunlight, and pests can take a toll on young plants, especially when they’re just getting started. Indoors, you can control these elements to maximize your plants’ growth and give them the best shot at thriving when they are eventually transplanted outdoors. In regions with a short growing season, starting seeds indoors lets you get a jump on the season and have more time to grow, resulting in a greater harvest. Read more about starting seeds indoors.

What is Planting by the Moon?

Planting by the Moon (also called Gardening by the Moon) is a traditional way to help plan your above- and below-ground crops. Here’s how it works:

  • Plant annual flowers and vegetables that bear crops above ground during the light, or waxing, of the Moon. In other words, plant from the day the Moon is new until the day it is full.
  • Plant flowering bulbs, biennial and perennial flowers, and vegetables that bear crops below ground during the dark, or waning, of the Moon. In other words, plant from the day after the Moon is full until the day before it is new again.

Old-time farmers swear that this practice results in a larger, tastier harvest, so we’ve included planting by the Moon dates in our planting calendar, too. Learn more about Planting and Gardening by the Moon.


Photo by Surachet Khamsuk/

Which Seeds Should You Start Indoors?

A lot of seeds can be started indoors, but some are better off being sown directly into the garden. Some crops, such as root vegetables, do not transplant well and should be started outdoors. Tomatoes and peppers, on the other hand, can tolerate being transplanted and are typically started indoors. Consult our table, below, to see where other crops are commonly started.

Whether you start seeds indoors or outdoors also depends on the length of your growing season, as well as your climate. In cool regions with shorter growing seasons, most seeds should be started indoors, as they need to get a head start on the growing season and should be protected from potentially-freezing spring temperatures. In warm regions with longer growing seasons, more seeds can be started outdoors, as they don’t need as much of a head start on the season and are not in danger of being killed by a spring frost.

When Should You Start Seeds Indoors?

For most crops, you should start seeds indoors about 6–8 weeks before your last spring frost date. This gives the plants plenty of time to grow large and healthy enough to survive their eventual transplanting to the garden. Consult our Planting Calendar to see the best time to start seeds in your area.

When Should You Transplant Seedlings?

When seedlings have grown too large for their seed trays or starter pots, it’s time to transplant. If it’s not yet warm enough to plant outdoors, transplant the seedlings to larger plastic or peat pots indoors and continue care. If outdoor conditions allow, start hardening off your seedlings approximately one week before your last frost date, then transplant them into the garden. Get more tips for transplanting seedlings here.

Browse Planting Calendars by State or Province

The Best Time to Plant Grass Seed

Moderate spring weather helps spring-planted grass seed flourish.

Why Spring is Best for Warm-Season Grasses

Warm-season grasses germinate best when soil temperatures are consistently in the 65°F to 70°F range. This generally corresponds to daytime air temperatures near 80 F or more. Planting in late spring and early summer gives warm-season grasses the advantage of warm soil and early seasonal rains, which help keep soil moisture available during germination and establishment.

As with cool-season grasses, best warm-season planting times vary by location. In California, mid-April to mid-May is prime time for seeding warm-season lawns.3 In central and southern Arkansas, lawn owners plan their warm-season grass seeding for late May through June.2 It’s tempting to get out and seed at the first hint of spring, but patience pays off. Wait until all danger of frost has passed and soil warms. Cold, wet soil is a recipe for poor germination, rotting seed and disease. Your county extension agent can help with expected frost dates and timely advice when unexpected weather conditions factor in.

As a general rule, warm-season grasses planted at least 90 days before the first fall frost have time to establish well before winter. These summer-loving grasses go dormant once temperatures drop near 55°F, so late-planted seedlings can’t prepare for what’s ahead. With proper timing, warm-season grass seed gets a natural boost from summer’s warmth and a full season of active growth and development before cooling temperatures bring on winter dormancy.

One exception to the spring seeding rule for warm-season lawns is when overseeding with a cool-season grass, such as perennial ryegrass, for temporary winter color. Do this in fall, once temperatures drop and warm-season lawns begin to go dormant and lose color.

What to Expect From Newly Planted Seed

Proper timing allows all types of grass seedlings to root well and get established before natural stresses hit. What that looks like in your lawn can vary depending on your grass type, your growing region and the conditions in any given year.

Grass types and varieties vary in their natural germination speeds. For example, cool-season Kentucky bluegrass germination can take two to three times as long as tall fescue varieties. Similarly, warm-season Zoysia grass may take two to three times longer than Bermudagrass. In addition, many seed products include a mix of seed types that germinate at different speeds.

Whether you’re repairing bare spots, overseeding an existing lawn or starting from scratch, you can generally expect grass seedlings to emerge within seven to 21 days when grown under proper conditions. It may take another three to four weeks of growth before grass is long enough to mow. For fall-planted seed, this can mean waiting until spring for your first mowing. Some grasses, such as Zoysia grass, may need several months of growth to fully establish.

Much of the initial growth of new grass seedlings happens underground, where you can’t see it. New roots get grass firmly established, prepared for the seasons ahead, and positioned for strong, rapid growth when their peak season arrives. With proper timing, new grass seedlings compete well for light, water and nutrients and fight off lawn diseases and pests, including lawn weeds.

How To Grow Cactus From Seed

The time a cactus takes to grow from seed depends on the species and the climate. Cactus seedlings are quite sensitive, and they continuously need protection from direct sunlight. If possible, keep them indoors then introduce them to the outdoors slowly.

How long does a seed take to germinate?

The seed germination time depends mostly on the species and where you are growing your cactus. When you choose to grow your cactus indoors, they are more likely to germinate fast. Indoors are a more controlled environment, and seed germination can take between three months and several months.

On the other hands, if you decide to grow your seeds outside, they take years to germinate. Here, cacti will have to wait for the ideal moisture and temperature for them to grow unlike indoors where you have the option of placing them in a light shade windowsill.

Cactus seedlings need proper care and protection. They need sun protection for the first few years until they are about 3 inches long. Placing them indoors or in a shaded place is the best way to help in seed germination.

When they are about 1 inch long, you can start introducing them to the sun. Go increasing the light intensity and keep them off if they start scorching. If after some time you comfortably leave them on the windowsill consistently, then it may be time to take them outdoors.

Why Grow Seeds?

You may be wondering why opt for cactus seeds instead of propagating from cuttings? Here are a few reasons:

Seeds are an inexpensive option because they may end up costing a few cents. You can even collect them from your other cactus plants or get them from a friend.

It is easier to get different species that may not be available as plants.

With seeds, you can easily give away as gifts to friends.

When you notice cactus seedlings starting to develop, you can gradually begin to remove the transparent cover that covers them. However, when to remove is quite essential, and it will depend on the species. The best way to ascertain when to remove is when the seedlings start developing spines.

When removing the cover, don’t just remove it wholly, start by cutting sections of it to introduce the plant to the change. Cacti the size of a marble, which are usually about six months are okay for planting in pots.

With seeds, you get to see the whole life cycle of the cactus from the very beginning

The Steps To Growing Cactus From Seed

1. Acquiring the seeds

The first step to planting cactus seeds is purchasing them. Most garden supply stores will have the seeds, and you also have the option of buying online. The good thing about buying online is you can select your preferred species through a simple click on your laptop and delivery is done to your doorstep. Some stores will even sell the seeds in packets of different species.

The other option would be to pick your own seeds from already blooming cactus in case you grow them. The seed pods are usually some brightly-coloured off-shoots that bear flowers. Once the flowers fall off, what is left is the pod.

Sowing your seeds in late winter or early spring is the best time because it will give the seedlings ample time to grow during summer.

2. Harvesting from the pods

As mentioned, if you decide to harvest the seeds yourself, then you need to remove the pods. It is recommended to remove the pods when they are still damp but not wet. The seeds are usually inside the pod.

Once you remove all mature pods from your cactus, you need to remove the seeds. Using a knife, slice the pods and scrape off the seeds. Note, seed color varies from different species. Some are usually black or have some reddish dots. They also vary in size; some are extremely small.

3. The soil you plant the seeds in is significant

One thing about cactus seedlings is that they are intolerant to poorly draining soil. You need to protect your seedlings from common cactus problems such as bacteria and molds, which means the soil needs to be sterilized.

To sterilize the soil, you can bake or microwave the soil mix.

Sterilizing soil

There are various ways you can sterilize your soil before using it to plant the seedlings.

  • Using steam

You can steam the soil using a pressure cooker. Pour in a few cups of water into the pressure cooker and place shallow pans of soil (not more than 4 inches deep) over the rack top. For each pan, cover it with foil paper and then close the lid. Steam for about 30 minutes.

In case you don’t have a pressure cooker, pour an inch of water into a sterilizing container and place soil-filled pans (usually covered with foil) on a rack on the water. Cover the container and steam for about 30 minutes.

One thing about cactus seedlings is that they are intolerant to poorly draining soil

For both methods, after steaming, allow the soil to cool while wrapped with foil until you are ready to use.

  • Using a microwave

If you decide to use a microwave, fill microwave-safe containers with moist soil and covered with a lid. Don’t use foil here. Ensure there are ventilation holes on the lids to prevent pressure buildup.

Heat your soil for 90 seconds. Leave the soil to cool by covering the ventilation holes with tape.

The other option would be putting two pounds of moist soil into a polypropylene bag. Place the soil in the microwave with the top left part open to allow ventilation. Heat the soil for about 2minutes 30 seconds full power. Once you are done, close the bag and allow it to cool.

  • Using an oven

For the oven, you need a container that’s specific for oven use. Put soil about 4 inches deep into the container and cover it with foil. Using a thermometer, place it at the centre and heat at 180F for about 30 minutes.

Once the time lapses, allow the soil to cool and remove the foil only when you are ready to use the soil.

When coming up with a soil mixture for your cactus seedlings, you need to find the right proportions for your seedlings to germinate. You will need

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

First, the base of the soil mixture should be pumice stone and the cactus soil. Start by removing any chunks in the cactus soil because they may potentially be a breeding place for bacteria as well as not drain water well.

Once you sift the cactus soil, mix with the pumice or granite stone. In case you don’t find pumice stone, you can use limestone screenings, which is also a cheaper option. Make sure the pumice is more by about 10% than the cactus soil.

Pour the mixture where you intend to plant the seeds and avoid packing it in, let it stay as natural-looking as it can. Since seedlings are quite small, using a 2-inch pot is sufficient. You can even use existing materials to act as pots for the seeds.

In the case that you are reusing pots, make sure you clean them thoroughly to prevent potential pests from killing the seedlings even before they germinate. To clean them, you can use bleach water and rinse thoroughly.

What these seeds need is a high-drainage soil. Make sure you moisten the soil but make sure the water drains completely.

Spread your cactus seeds on top of the soil, don’t force them into the soil. You can then cover them with a thin layer of either sand or cactus soil. The reason for not burying them deep in the soil is because they only have small amounts of stored energy which may not reach deep into the soil before running out.

Make sure to label your containers once you spread the seedlings. It is crucial especially if you plant species by species in different containers are they are great so that you can take specialized care on each species. You don’t want to have difficulties when growing them because some species are too similar to each other and you may confuse one for the other.

4. Exposing the seeds to the sun

After soil moistening and covering the seeds with sand, you need to cover them in a transparent lid or plastic wrap. Place your seeds in a strategic location, preferably indoors, where they have access to the right amount of sun. Consider placing them on a sunny windowsill.

Don’t place them outside because they don’t like intense sunlight. The purpose of the transparent lid retains moisture and helps the cacti sprout as well as allowing light to reach the plant.

Monitor your seedlings carefully. If they start turning purple or becoming red, the chances are that they are getting sunburned. Reduce the amount of light access.

During the initial stages, as much as the seeds need sun, they need the heat more. Warm areas of the house like the kitchen are ideal. However, you can also purchase a heating mat that you place under the seed containers is a way to boost germination.

Heat and light are essential as the cactus grows to avoid retaliation where the plant grows thinner and soft such that it breaks when touched.

Place your seeds in a strategic location, preferably indoors, where they have access to the right amount of sun

In most cases, cacti need a temperature of between 70F and 90F for germination.

5. What to do when germination starts

Like earlier mentioned, cacti grow slowly, and you need the patience to see them through the whole process. After planting and having the right light and temperature, you should see your seedlings start germinating. It could take a month or more before they do.

Tiny spines start forming at this stage. This is your cue to let the plant breathe away from the plastic wrap or transparent lid. However, do it gradually, leave the top open for a few hours during the day and then go increasing the hours.

Keep doing this until you establish that the cactus doesn’t need the wrap.

Keep in mind that when you uncover the cactus, water evaporates much faster, which will need you to have a watering schedule to avoid the plant dying.

Fresh or distilled water is ideal for preventing the growth of bacteria and algae. If you feel your tap water tastes like chlorine, don’t use it on your cacti. Since the roots are quite tender, using water with chlorine will burn them. This could end up in killing the cactus.

Even as the seedlings sprout and seem to be doing well, the truth is, below the ground, the roots are still at a tender position and can’t adequately absorb enough nutrients. Keep the seedlings in the plastic wrap until they overgrow. The high humidity is what facilitates nutrient and water absorption in the roots until they are strong enough.

Some species don’t have spines, so an indication of growth is when the seedlings sprout. Make sure you don’t leave any water on the soil. Keep checking for signs of overwatering. No standing water should be in the container. You can dip your finger into the soil to feel how dry or wet it is.

When germination occurs, keep the same timetable you had when you started watering them. Be on the lookout of certain signs such as seedlings thinning, which could be a cause of poor light. The algae may be top of the soil, which could be a cause of overwatering. A fungus infected cacti will start having black spots.

6. Repotting

When the seeds are overgrown, it is now time to repot. Choose your potting container wisely as you need one that drains quickly. You need one with drainage holes so that during watering, the excess water drains to avoid root rot.

Terracotta and unglazed ceramic pots are some great examples of good drainage pots. However, other types of containers can also work, but the key is getting one that drains water quickly and doesn’t leave the soil clogged with water.

Even as you get the ideal container, how much you water the cactus also contributes to whether your plant rots or not.

Naturally, as cactus grow slowly, they may take even a year to reach the size of a marble. At this point, you need to repot to give it room to thrive well. Get the right pot size because getting small-sized one prevents the plant’s proper growth.

Once you remove the cactus from its previous plastic wrap, using the same formula you used for its last soil, make a new mixture. After making it, place the plant in the container then pour in the soil mixture.

Water the mixture after 3-4 days and make sure you don’t use any plastic wrap or lid to cover the plant.

Terracotta and unglazed ceramic pots are some great examples of good drainage pots

7. Recovery time after repotting

Once you repot, allowing the plant to take in the new changes helps it avoid any problems. Repotting can be stressful to plants, and they need recovery time. If you previously placed it near a place with ample sunlight, try keeping it in the shade for a few days until it recovers. You can then re-introduce it to the sunlight slowly until it can fully take on the heat.

Unlike other potted plants, cacti have low water requirements. They are succulents, and they often store water to use when the soil dries up. A general rule of the thumb is to wait until the soil dries before watering the plant again.

Once your plant grows, you can even water monthly. During winter is when their water requirements are low for most species. At this time, only water when the plant needs it. You’d rather have an underwatered plant than an overwatered one because it is easier to deal with insufficient water than excess.

During the growing months, use a cactus fertilizer to help in the growth process. Cacti generally need a lower amount of fertilizer than the rest of the plants.

The above process should help you grow your cactus seamlessly from seed. If you want to experience the joys of watching it grow from the seeds all the way up, you can do this effortlessly.

Related Questions

How do you ensure your cactus germinate faster? Usually, cactus have slow growth and may end up taking years to grow. However, you can help them germinate more quickly. Soak them in warm water for about 30 minutes as this will loosen up the seed coat and activate germination.

How does a cactus produce seeds? For a cactus to produce seeds, its flowers have to undergo pollination. Pollen has to be transferred from one plant to another by insects or birds. Once pollination takes place, fruits develop that contain the seeds. One cactus plant has the potential of producing a million seeds.

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