Learning how to germinate cannabis seeds is the first step to growing marijuana, but it's not as easy as many aspiring cultivators think. A step-by-step guide describing the best way to germinate your cannabis seeds. This germination method is ideal for the indoor and outdoor grower. Jorge Cervantes, veteran marijuana cultivator and author of “The Cannabis Encyclopedia” shares his process for germinating cannabis seeds into healthy sprouts.
How To Germinate Cannabis Seeds
Cultivating cannabis from a seed is not as easy as many beginner growers might think. Various factors are involved which will ultimately determine if the cultivator is successful and has a large harvest, or if they fail and have to go back to the drawing board. Learning how to germinate cannabis seeds is the first step to becoming a cultivator.
Some cannabis cultivators prefer to start with cannabis clones versus marijuana seeds. Each route has its own advantages, however, seeds are typically easier to acquire than clones. While clones and seeds will both do the trick, seeds also seem to be a more popular route in many areas.
It’s worth noting that purchasing cannabis seeds online is illegal and often results in less than desirable seeds being acquired by the buyer. Look for legal cannabis seed options in your area. Many reputable licensed cannabis dispensaries sell cannabis seeds, with strain options varying.
How Do You Know If A Cannabis Seed Is Viable?
If you consume cannabis long enough, chances are you will come across a seed in your cannabis flower. Whether you want to try to germinate the seed immediately, or save it for down the road, it is important that you know if the cannabis seed is viable to be germinated or not.
Viable cannabis seeds tend to have a darker color with shades of grey, black, and/or brown. A really good cannabis seed will typically have a ‘tiger stripe’ across it. Another way to tell if a cannabis seed is viable is by touching it (make sure to wear gloves when handling cannabis seeds). A quality seed should withstand a bit of a pinch. If the seed collapses under a little pressure, then it wasn’t viable.
How Do You Germinate Cannabis Seeds?
Germinating marijuana seeds is not difficult, although it does take attention to detail and the right environment. Successful germination takes the right amount of moisture, the right temperature, and a decent amount of light (sunlight or artificial light from low-intensity grow lights).
Arguably the easiest and most cost-effective way to germinate a cannabis seed is to place it between wet paper towels (often referred to as “the paper towel germination method”). Add a bit of water to the paper towels and squeeze out the excess water.
You want the paper towels to be moist but not dripping water. Place the seed(s) between the moist paper towels, place the paper towels in a sandwich bag to lock in the moisture, and put it on a window ledge where it will get some but not too much light. Keep the paper towels moist until the germinated cannabis seeds are ready to transplant.
If the temperature of the room is too cold (below 55 degrees Fahrenheit), consider using a heating mat, which can be found at most department stores in the gardening section. The success rate of the paper towel method is high as long as the cultivator keeps a close eye on the process until the germinated seed is ready to be transplanted into potting soil, peat pellets, or a different growing medium.
Various products such as “rapid rooters” can be incorporated into germination strategies, however, they are not as cost-effective as the paper towel method.
When Is The Seed Ready To Be Transplanted?
Watching a cannabis seed germinate can be a lot like waiting for water to boil — it takes time (typically a couple of weeks). The seeds will eventually crack open and a white root will shoot out of the cracked cannabis seed shell. The white root is often referred to as the taproot. Once your sprouting seed has a strong taproot (an inch or so) it is ready to be transplanted.
Find a two-inch container for your grow space, fill it full of soil (or your preferred growing medium), and poke a hole where the seed will be placed. Using tweezers, place the seed with the taproot facing down in the hole. Then, cover it with soil.
From there, you can grow the cannabis seed into a large cannabis plant. One downfall to cultivating cannabis from seed is that you won’t know if the marijuana plants are male or female for several weeks. If the young plant proves to be male, then it is basically useless. Using feminized cannabis seeds is a good way to ensure that the plants are not males, saving you quite a bit of time and headache.
Continuing Your Education
Cultivating cannabis is a never-ending educational journey. Even the most experienced cannabis cultivators will be quick to tell you that they are always learning and seeking out cultivation information.
A great way to learn more about the cannabis cultivation process from seed to harvest is via Green Flower’s Cannabis Cultivation Certificate Program. The program is led by true cultivation experts and involves insightful course materials. If you are looking to increase your cultivation knowledge this is a great way to do it!
How to Germinate Cannabis Seeds
Germination is the beginning of your cannabis seeds’ life and is easy to master. At this crucial stage, seeds grow and sprout into young seedlings. The best genetics deserve the best start, and all you need is two plates, some paper towel, and water. Apply the best germination method today and enjoy a great harvest.
1. Germination set-up
Prepare the first plate by lining the inside surface with two to three layers of damp paper towel. Drain excess water from your plate.
Place cannabis seeds on the top surface of the damp paper towel. Approximately three per plate; ensure they are not touching but are evenly spaced apart.
Add only a few layers of damp paper towel on top of the seeds, and let any excess water drain from the plate. Too much water lowers the chance of successful germination.
To complete the set-up, place the remaining plate upside-down and on top of the first plate, resembling pearls inside a clam.
Cannabis seeds need a dark, warm, and humid atmosphere to germinate.
Around 21°C (70°F) is perfect. Check the paper towels every second day and if required, spray with water to keep conditions moist for your seeds.
After a few days, tiny roots will begin to emerge. Congratulations! Your seeds have survived their first stage of life. Don’t worry if some of your seeds have not yet changed, they may just need a little more time as germination can take up to 14 days.
3. Plant of the seeling
Once the roots are a few millimetres long, they are ready to be delicately transferred to a small container filled with your growing medium of choice (rockwool, coco-fibre, or soil).
Make a hole in the growing medium that is 2 – 5 mm deep. Use tweezers or your fingers to transfer germinated seeds gently into the hole (root pointing down) and lightly cover with a fine layer of your medium. Do not pat it down too hard. The stem and the first tiny set of leaves, called cotyledons or ‘seed leaves’, should begin to emerge 24 to 72 hours after the seeds are planted.
4. Supplying a light source
Seedlings must be exposed to sunlight once they sprout. Ensure this is a gradual process as too much heat causes stress and will stunt growth.
Find a sunny place where you can begin to increase sun exposure, such as a windowsill. Ensure sun exposure is increased by an hour or so a day.
For an indoor plant you can use a fluorescent light (keep normal distance from bulb) or HID lighting (50-80 cm from the bulb).
Take care in the first week or two, as seedlings are still quite delicate and sensitive to the elements. They won’t need a lot of attention until the vegetative stage so avoid overhandling.
Germination is the beginning stage of the growing cycle, and this easy-to-follow guide gives your premium genetic cannabis seeds the best start to life. Whether you are a first-time home grower or a well-seasoned gardener, share your experience or any questions in the comments down below, as well as your tips and tricks!
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Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.
24 thoughts on “How to Germinate Cannabis Seeds”
Hi, Once seeds have sprouted, how long can or should you leave them to grow under 24 hr lights before moving to your outdoor garden?
Good afternoon Ken,
I hope you’re having a great day.
For the vegetation process, a light schedule of 18 hours of light, and 6 hours of darkness is preferred. Many growers get plants acclimatized to outside by placing them in a window, or under direct sunlight for a few hours a day.
Thanks again, and have a great day!
Hello everyone, all these suggestions are wonderful but I think a lot of you make it sound a little overwhelmingly. I’ve been very successfully cultivating for decades and I’ve always just placed my seeds, be it 1 or 100, in between 2 folded sheets of tissue which I’ve made wet with tap water. I then place them on a tray or plate in a warm dark area , such as an airing cupboard and leave for how ever long they take usually, 12 to 24 hours. The ONLY thing I do which takes effort is PH balance the water I germinate them in and I’ve only lost 5 seeds in nearly 40 years .
Good afternoon Paul,
I hope you’re having a good day,
Thanks for sharing your experiences with germination. pH balancing is a great tip You also might be interested in our new Jamaican Pearl Feminized Grow Report
Thanks again, and I hope you continue to enjoy the blog,
I lightly score my seeds by shaking them inside a rolled up piece of sandpaper – sandpaper side on the inside before leaving them in a cup of water for a few hours to hydrate. I then place them between wet (good quality) paper towel per instructions above. I find using an old plastic takeaway container with a heatmat below keeps the humidity high and with good end results.
Good morning Jonny,
Thanks for sharing your methods for germination with us, the heat mat and low-humidity are great tips!
Thanks again, and I hope you continue to enjoy the blog,
I have found out that the best and fastest way is to take a glass of clean/filtered water and place the seed right on top of the water (floating – NOT immersed in it!). If the seed is viable it will sprout in no more than 48 hours. Right after that you plant it in your pot/soil etc and you’re done.
Good morning Mary Jane,
Thanks for your support, and for sharing your experiences with germination!
You might also be interested in our article on The Life cycle of Cannabis: From seed to harvest.
Have a great day!
What happend if they sink I had em sink they came out fine
Once you put the seeds in water they normally won’t sink straight away, leave it for around 5 hours and then tap your seeds and they all should start sinking if they don’t then they won’t work. But still leave them over night and tap again and take out the ones that didn’t sink and throw them away or plant if you want to try your luck.. take all the other seeds out and follow instructions above you’ll see the open within a day..
Are you saying they sprout in the glass of water and don’t “drown”?
No, don’t leave the seeds in water for longer than 24 hours or they will drown.. after around 12 hours all your seeds should have sunk if they haven’t then just give them a tap and they will sink.. then take them out and follow the paper towel and plates instructions
Take aluminum foil flatten it out and put on top of your dirt it detects planes and grow it just like a tomato plant
Good morning Tammy,
Thanks for getting in touch with Sensi Seeds, and sharing your germination method with us!
Thanks again, and I hope you continue to enjoy the blog.
With best wishes,
Detects planes? Like magnetic? I’ve always has best success 24-48 hours soaked In water, spring water if possible. Usually do this in a shot glass, once they pop I’ll take a paper towel fold so it’s 2 layers then fold once more so you know where center is. Dump the seed in the middle of the edge and the true center (reason we folded a 2nd time)as well as the water just enough to saturate the paper towel. Do not soak! Carefully with the seed in the middle using sterile tweezers turn so the tap is growing down. This will prevent circling and tangling if doing multiple seeds. Now you can fold the other half so your seed will be “sandwiched” between 2 layers. At this time carefully take a corner and the waters attraction should keep your paper towel from unfolding but just in case be gentle. Holding it from 1 corner you can dangle it over a cub or the original shot glass so any extra water runs off. Now take a standard zip or press n seal sandwhich bag and slide your napkin in Carefully . REMEMBER which way was down! Work the air out making jt flat snd seal. Find a temperate dark area around 70°. A cabinet works we’ll as your going to prop it up with taproot facing downwards. Now just close it up and wait in 24-72 hours checking once a day. In rare cases you could have a 1/2″ tap root in the first 24 hrs some may take 4-5 days. Once the tap is about 1/2″-3/4″ long its ready for transplant into its first small pot. With this paper towel method I typically have 100% success.
Can you leave your seed to develop longer roots in the germination phase and can this make them better to grow or is a big no no?
Last year, I had 2 seeds that had really long roots with lots of secondary roots coming out when they were planted, one of which died after a couple of weeks and the other grew into a huge plant.
The other two seeds only had a short germinated growth and both died almost immediately after planting so not sure what I can learn from this…lol
Appreciate any thoughts and advice
Unfortunately, legal restrictions mean we can’t answer grow-related questions or give grow advice on this blog. However, other readers of this blog will often answer questions like yours.
Please check out the following articles on our blog which I think you may find of use, and I hope you continue to enjoy the blog!
With best wishes,
How often do you water and how wet should the plant be? Please.
Also if they are outdoor plants do you need to keep them covered with clingfilm for a wee while or do you just hope for the best. Thanks
This article, about how to water cannabis plants, should answer your questions. I can’t help you with the clingfilm one though, as it depends on the climate. Good luck, and happy gardening!
With best wishes,
Just drop the seeds in water, they will sprout , don’t have to use a towel and check it all the time , drop it in the water , let it float then it will sink and the root will grow out ,let the root get 1/4 inch and plant it where it’s going to grow , 8 hours sunlight starting as soon as it is out of the soil. Always grows great , don’t have to transplant from cup to gallon to bigger and bigger , if it’s growing outside put it where it stays , always does just fine.
Good afternoon Graham,
Thank you so much for sharing your experiences with germination.
Thanks again for your comment, and I hope you continue to enjoy the blog.
Have a great day!
I recommend this article to all breeders and cultivators who plans to germinate seeds and to some who don’t know how to germinate seeds, this article has the best and perfect ways on how to do it.
I have large bay windows at my condo which get about 11-12 hours of light per day. They are tinted but warm. I grow other indoor plants there perfectly. Is an ok place for my pot plants?
This sounds like a great place for all kinds of plants! I recommend you have a look at autoflowering varieties, as otherwise light pollution may negatively affect the flowering cycle. Good luck, and happy gardening!
With best wishes,
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How to Grow Weed: Germinating Cannabis Seeds
Jorge Cervantes shares his process for germinating cannabis seeds into healthy sprouts.
The gardening season is booming in North America, and it’s high time to start some tiny seeds that can grow into potent plants, says Jorge Cervantes, veteran marijuana cultivator and author of “The Cannabis Encyclopedia”.
1) Soak seeds overnight in a glass of plain water. They may float on the surface at first but should sink to the bottom in a few minutes. Make sure seeds get good and wet so that water penetrates the outer shell and growth is activated. Do not let seeds soak for more than 24 hours, or they might get too wet, suffer oxygen deprivation and subsequently rot.
2) Remove seeds from the water. Pour water out onto two paper (or cloth) towels on a dinner plate. Fold the towels over the seeds to cover them.
3) Drain the water from the dinner plate by tipping it to the side.
4) Place the seeds in a warm location (70°F–80°F; 21°C–27°C), making sure they are in darkness. Some gardeners go so far as to set the plate in a vertical position (so taproot grows downward). The seeds can also be set on a grate for drainage and air circulation.
5) Check moisture level of towels several times a day, watering once or twice to keep them evenly moist. DO NOT LET THE TOWELS DRY OUT! Let excess water drain away freely. The paper or cloth towels will retain enough moisture to germinate the seeds in a few days. Each seed contains an adequate food supply for germination. Prevent fungal attacks by watering with a mild 2 percent bleach or organic fungicide solution.
6) In a few days, seeds will sprout. Once the germinating cannabis seeds have sprouted and each seed’s white rootlet is visible, use tweezers to carefully pick up the fragile, germinated seeds and plant them. Do not wait for the white rootlets to grow more than 0.25 inches (1 cm) before planting, or growth could slow. Plant each germinated seed with the white root tip pointing downward. Take care not to expose the tender rootlet to prolonged light and air. Cover germinated seeds with 0.25 to 0.5 inches (1-2 cm) of fine, moist planting medium.
Other Tips for Germinating Cannabis Seeds
Over and under-watering are the biggest obstacles most gardeners face when germinating seeds and growing seedlings. Keep the soil uniformly moist but not waterlogged. Do not let the growing medium’s surface dry for long. Setting root cubes or planting flats on a grate allows good drainage.
A shallow flat or planter with a heat pad underneath may require daily watering, while a deep, 1-gallon (3.8 liter) pot will need watering every three days or more. A properly watered flat of rockwool cubes needs water every three to five days when sprouting seeds.
When the growing medium’s surface is dry (0.25 inches [1 cm] deep), it is time to water. Remember, there are few roots to absorb the water early in life and they are very delicate.
Some seeds have a very hard outer shell (testa) and are difficult to germinate. Such testy cases can be softened or scarified to allow water to penetrate. To scarify, line a matchbox with a piece of fine-grain sandpaper or emery board. Put the seeds in the matchbox and shake for 10 to 15 seconds. Remove the seeds and make sure they have been scuffed a bit. Just a little scuffing will allow water to enter and set germination in motion.
1) Set seeds in a matchbox with an emery board or sandpaper on the bottom.
2) Close seeds inside the matchbox.
3) Shake matchbox for 10 to 15 seconds to scarify the seeds.
This is an excerpt from “The Cannabis Encyclopedia” by Jorge Cervantes, world-renowned indoor, outdoor and greenhouse cannabis cultivator. A veteran marijuana grower, Cervantes brings 30 years of experience traveling, studying and writing to bear in his best work to date.