Whether it’s your time to step into cannabis cultivation, or you’re just curious about the process, here we are, ready to learn how to germinate weed seeds.
Also referred to as “popping seeds” or “popping beans,” germinating seeds is the first step in growing cannabis from seed (growing from clones is a bit of a different story). This article contains everything you need to know before you germinate your seeds, and the best method to go about it.
(Note: This guide is for educational purposes only and not intended to be followed if it would place you at odds with local and/or federal law.)
What Is Germination?
Germination is the process by which a new plant grows from a seed. Every plant seed, not just cannabis, contains a tiny, ready-to-grow dormant plant, curled up around a tightly packed store of nutrients. When you plant seeds of any kind, these seeds germinate as the first step of their life.
When plants produce seeds, they send off these potential offspring into the world, ready to spring into action when the conditions are right: usually a dark, warm, moist place. The darkness paired with moisture are key indicators to the seed that it’s time to wake up and start growing a plant from the soil (or whatever other growing medium) it’s in. Essentially, telling the plant it’s spring time, and time to start growing!
When those conditions are met, the plant inside the seed awakens from its dormant state, sends a tap root down into the soil, sends its first stem up towards the air above and the seedling starts to grow b!
Why Do We Germinate Cannabis Seeds?
Germination happens in the wild all the time, since it’s the process by which plants produce offspring via seed. When we’re growing cannabis from seed, we want to control as much of the process as possible to limit any potential issues, starting with germination of our cannabis seeds.
There is another way to grow cannabis, from “clones,” but you need to have a mother plant to begin with! How do you get that mother plant? Often, through your chosen cannabis seed.
For breeders, germination is a crucial step in the pheno-hunting process (phenotype hunting), in which dozens, and sometimes hundreds of cannabis seed are germinated and grown, to the find the proverbial needle in the haystack of the perfect marijuana plant, to then clone from.
For beginner growers, especially those that can’t find themselves cannabis seedlings, purchasing from cannabis seed companies is the only way to get their first plant, so learning to germinate cannabis seeds will be essential for any new grower getting started.
What’s the Best Way to Germinate Cannabis Seeds?
There are a few ways to handle germinating your seeds. This most basic, tried and true method requires just a little bit of household equipment and a few days! Put frankly, cannabis germination is something that is hard to mess up, so you should have “great success” with this method!
What You Need
- Two small side plates
- One or two sheets of paper towels
- Tap water (distilled/filtered, ideally but tap water usually works just fine)
- A warm, safe location you can leave them (70-90°F) that won’t get knocked over
- Cannabis seeds
Step 1: Stack & Soak
Stack your paper towels one on top of the other and fold them into a square. Then, soak the paper towels with your water. You don’t want them sopping wet (dripping) but they should be thoroughly dampened. Hold them up while they drip until they stop dripping altogether. Place them on one of your plates.
Step 2: Lay Out & Label
Unfold one fold of your paper towel, put it on your plate, and lay your cannabis seeds out, evenly spaced. We recommend adding some sort of label if you’re popping seeds of multiple strains, and include the date you’re starting them.
Step 3: Nighty Night!
Fold back the paper towel over the cannabis seeds to cover them, and place the second plate upside down, on top of the first plate, creating a dark, safe space for your seeds to start to come to life!
Step 4: Warm, Watch, Wait
The length of the taproot before transplanting is a bit of a personal preference, but we recommend waiting until there is at least a half inch of root. Carefully pick up the seed and place it in your growing medium – whether that’s soil, rockwool or coco – root facing down. Use tweezers to pick it up if you’re worried about being gentle enough!
If the seed coating didn’t shed from the cotyledons (the first two leaves on a seedling, pronounced “coddle-edens“), try not to remove it. You risk damaging the leaves and stem and the seedling should shed the seed cap on its own.
Make sure your growing medium is properly moist, using a spray bottle if you have one, to keep your watering gentle and seedling safe. Pouring water onto your seedlings can cause them to fall over, so be gentle.
Step 5: Transplant
Place the seeds in a warm location, ideally somewhere between 70°F-90°F, for a few days. Room temperature is fine usually. Too hot and you will dry out and cook the seeds. Too cold, and either it will take too long and the seeds will mold/rot before they sprout, or it won’t stimulate the seeds at all.
You’ll want to check the seeds frequently (daily is ideal) to make sure the paper towel doesn’t dry out. Just add more water if required.
After anywhere between three days and 14 days (yes, there can be that much variation!) you’ll see the tap root emerging from the seed! If you wait even longer, the seed can also shed, exposing pale, green, rounded leaves called the cotyledons. If kept in the dark too long they may appear more yellow than green, but that will go away in time.
Not all seeds will germinate, and you can just discard any duds. Give them enough time to make sure they’re not just late bloomers though!
You also might see tiny white fuzz on the root, but don’t panic – those are likely root hairs, not mold! Mold is very distinctive (when you know what you’re looking for); these roots hairs are still fibrous, and won’t drift away at a breeze or touch.
Step 6: Let There Be Light!
You’ll want to move your new seedlings in their growing medium to a location with a significant source of light, that’s on for anywhere between 18 to 24 hours.
Seedlings that don’t receive enough light will stretch to reach the light making them tall and gangly and risk damage. Seedlings with too much light can be stressed into submission. Generally, a cheap fluorescent light a few inches away is the way to go. A fluorescent grow light is enough light for the seedlings, without producing heat to stress them out. Eventually, you’ll want a more powerful grow light, though!
You’ll now want to consider adding a small, light fan to your grow space at this point as well, blowing very softly, so as not to blow the seedlings over, but just to provide a little resistance, allowing the cannabis seedling to stiffen up.
Now that you’ve got cannabis seedlings, you’re ready to take your growing to the next stage – vegetation – producing a big healthy plant that’s ready to either make clones or take into the flowering stage after a few weeks.
The taproot from your seedlings will shoot down towards the bottom of your grow container, as more roots extend from the taproot and spread throughout the container. Healthy cannabis roots are bright white, and at this stage of the grow it’s important to nurture those roots as best as you can.
Maintaining the proper pH of the soil or growth medium (5.8-6ish) and being careful not to over-water (a classic beginner error) is going to be crucial to maintain strong, healthy roots.
Other Germination Methods
Straight in Soil
Of course, most seeds in nature germinate straight in soil, and this is definitely an option when you germinate cannabis seeds as well, and many purists will recommend you do this.
That being said, in our opinion, the paper towel method is an easier way to maintain a consistently moist environment, suitable for your seeds during such a crucial step. It also allows you to remove any dud seeds before spending more time on them!
Other sites will also recommend you put your paper towel in a plastic sandwich bag. We’d caution against this unless you aren’t going to be able to watch your seeds for an extended period of time. The lack of oxygen and build up of moisture can cause unwanted molds and bacteria to find their way in.
If you’re having trouble keeping the paper towel moist from day to day, use a plastic sandwich bag but don’t close it, to help keep that oxygen flow moving and mold from settling in.
Optional Pro Tips
Pre-Soak & Scrape
Some folks recommend soaking their seeds overnight in a glass of water before beginning germination (and for some, rare and particularly stubborn strains, even scraping the seed coating to thin out the seed making it easier for the seed to germinate) but in general, neither of these techniques is required for the majority of seeds out there.
Some growers will also opt to soak seeds in a diluted solution of hydrogen peroxide to sterilize the exterior of the side prior to germination. Because some seeds are rare – and expensive – growers will do just about anything to improve the rate of their germination attempts and guarantee success.
How to Select Cannabis Seeds
Ready to get your hands on some cannabis seeds and get started? There are a few different types of seeds you may not have been aware of. Aside from picking the strain you want to grow, you’ll want to keep these things in mind as they can profoundly impact your grow.
Mature Seeds vs Immature
Pictured above is a mature seed next to an immature seed. The smaller, green seed can still possibly germinate, but it’s also possible it’s too underdeveloped. If you purchase seeds and they don’t look like the one on the left, you should definitely take it up with your seed bank.
Auto-Flowering Seeds vs Regular Seeds
Auto-flowering cannabis seeds can be purchased from many seed banks and have certain advantages over regular seeds.
Auto-flowering seeds contain the genes from Cannabis ruderalis, a subspecies of cannabis that does not begin its flowering stage of plant growth, based on the amount of light it receives. In other words, an auto-flowering plant will begin to flower on its own, and not depend on the grower changing the light schedule it receives.
Marijuana plants grown from regular seeds will only flower if provided a light cycle of 12 hours on, 12 hours off, or if some other major stressor causes the plant to pre-maturely flower.
What does this mean for you? If you have the ability to vary the light your plants receive, or want to produce a single harvest outdoors, then regular seeds are a good option for you.
Feminized Seeds vs Regular Seeds
Many seed companies also sell feminized cannabis seeds, which many people prefer to purchase for their first time. Regular marijuana seeds produced from a “male” and “female” cannabis plant have a 50-50 chance of being either “male” or “female.” In most cases (unless you are breeding plants) the female plants are the only seedlings you’ll want to keep.
Feminized seeds are produced by applying colloidal silver to a flowering and pollinated cannabis plant. Some growers lament that you increase the risk of cannabis plants developing hermaphroditism in the flowering stage and stay away from them.
Distinguishing between males and females in the garden can take experience, time, energy and resources, so feminized seeds provide a great solution for beginners, in particular.
Germinating your own cannabis seeds at home doesn’t have to be a daunting task, and we hope today’s lesson has given you the seed of inspiration to try sprouting weed seeds on your very own – Local laws allowing, of course. Happy growing!