by Nebula Haze
How to Germinate Marijuana Seeds So They Grow Fast
Plus, how to care for new cannabis seedlings…
We have a cannabis seedling germination page which has everything you need to know about all the different germination methods, but this tutorial is different. In this tutorial I’m going to share exactly how I do my seeds from beginning to end! Just follow these instructions and you’ll end up with healthy, fast-growing plants that germinate in just a few days. It’s basically fail proof!
There are a few different ways to get cannabis seeds, with the most common being ordering seeds online and growing seeds you find in weed that you buy. Learn how to research and find the right strain.
If you’ve found seeds, learn how to tell if they’re good to grow.
Here’s a picture showing several healthy and viable cannabis seeds
When it comes to new growers, it seems like the most fool-proof method (at least for me, and many of the new growers who write in) is the Paper Towel Method! It’s so simple, but there’s something about wet paper towels that a young seedling loves 🙂 Learn About Other Ways to Germinate Seeds!
Paper Towel Method – Place your seeds inside a folded wet paper towel (Important: use cheap brand!)
This method is hard to mess up if you follow the instructions! Place your seeds inside a folded wet paper towel, and place it between two plates so that the seeds don’t dry out. Surprisingly, the really cheap paper towels work the best because the seeds and roots lay on top without getting stuck to anything. This is important! The more expensive “cloth-like” paper towels (like Viva brand) aren’t good for germination because the roots actually grow into them instead of laying on top.
Wet a paper towel (use the cheapest brand you can find). If growing multiple strains, you may want to label the paper towel so you know which is which. Place each seed on the wet paper towel next to their label.
Cover with another wet paper towel
Add another plate on top to keep the paper towels from drying out
- Check on your seeds every 24 hours but try not to disturb them. When they’ve germinated, you’ll see the seeds have cracked and there are little white roots coming out.
- They should germinate in 1-4 days, though some seeds can take a week or longer (especially older and smaller seeds).
- Keep them warm if possible. One thing you can do to get seeds to germinate a little faster is to keep them in a warm place (75-80°F). Some people use a seedling heat mat but in most cases that’s unnecessary. I leave mine near a sunny window. I usually put a thermometer in the same place to make sure it’s not too hot or cold (or just check the plate with your hands)
Here are those seedlings about 2 days later. Be extra careful when removing the paper towels. Don’t let the seeds roll around or you won’t know which is which! This is when you’ll be glad you used cheap paper towels, as they are much easier to peel off without disturbing your seedlings.
You can see some of the seeds sprouted, but some of them haven’t yet. That’s totally normal! Each seed is different. If this happens to you, you have two choices. You could plant the ones that have already sprouted and let the other ones stay in the paper towels until they germinate. Or you could just put all the seeds in Rapid Rooters now, and hope for the best as far as the slow-sprouting ones. It’s up to you. Letting the unsprouted seeds stay in the paper towels longer improves the germination rate in my experience, but it’s simpler (easier) to move them all at once.
Now it’s time to get your Rapid Rooters! Alternatively, you could place your sprouted seeds directly in the final growing medium (coco or soil). I think these help them get started, but I’ve grown many successful plants by just putting the germinated seed directly in its final home.
The Rapid Rooter should be cut open lengthwise. I use big scissors but you could also use a knife.
Gently place the germinated seed inside, root down. Place the seed close to the surface so it doesn’t have far to go.
If you have a root that is curved or bent, don’t try to straighten it out. Open the Rapid Rooter and lay the germinated seed down gently. It will naturally lay on its flattest side. When you slowly close the Rapid Rooter, the bent parts of the root will end up in the “crack” of the Rapid Rooter that you cut to split it open from the side.
Most seedling plugs will go back into place easily, and you’ll barely be able to tell it’s been opened. I love Rapid Rooters because the texture of them causes the seeds to stay in place and not “fall down” further into the hole once you’ve got the Rapid Rooter closed.
4.) Prepare Your Soil, Coco or Hydro Tub
While that’s happening, set up your soil, coco or hydroponic tub if you haven’t already. It will still be a few days until your seedlings arrive, but you want to make sure to have everything ready before the seedlings need to be planted.
If in soil or coco, water your container right after putting your sprouted seed in the Rapid Rooter. This will give it some time to dry out before you install your seedling, so your new roots will have the perfect wet-but-not-too-wet environment in a few days! Remember, seedling roots love a good mix of air and water.
You won’t be watering this thoroughly again for a while to avoid overwatering a young seedling, so by watering thoroughly now, you know there will be some amount of water throughout the whole growing medium.
5.) Water the seedling in the Rapid Rooter until you see a root out bottom, 1-2 days.
Make sure to always keep the Rapid Rooter moist but not soaking wet and give plain, pH’ed water.
Since your seed has already sprouted and been in placed into the right growing position, it’ll often pop its head out within just 12-24 hours! Sometimes you see just the leaves, but often you actually see the seedling push the shell above ground.
Don’t touch the shell! Like a butterfly coming out of a cocoon, the seedlings gain strength during the process of pushing off the shell.
If you manually remove the shell for the seedling too early, you may feel like you’re helping, but sometimes the leaves have trouble opening afterwards. This is because there’s a “film” that can get stuck on the leaves, which would typically come off with the shell but may get stuck to the leaves if the shell comes off early.
Plant leaves still usually “break free” from the film eventually but it just goes to show that sometimes the best thing you can do for your seedlings is have patience and leave them alone. Shells usually falls off naturally as the seedling grows.
That being said, if you have a seedling that’s stuck in a shell for multiple days, sometimes you may need to go in and help. But try to let the seedlings break free from the shells themselves, if possible.
Don’t use a dome on seedlings unless it’s very dry where you live. If you do use a dome, consider keeping a vent open and watching the humidity. A young seedling doesn’t require as high humidity as clones (which are what the domes are designed for), and seedlings tend to get “wet feet” and stop growing as fast in constantly wet conditions.
Water your seeding in the Rapid Rooters until you see a root coming out the bottom. Keep Rapid Rooters moist but not wet. During this time, give seedlings bright, but not too bright light. A fluorescent (CFL) bulb kept several inches away works well! I’ve left mine on the kitchen table next to a sunny window, and that’s also worked fine for me as long as it doesn’t get too hot.
You should see a root come out the bottom in just a day or two!
After you see your first root, it’s time to…
6.) Put Seedling in its New Container!
Dig a hole half the size of the Rapid Rooter, and place your seedling directly inside. You can bury the Rapid Rooter all the way, but having it stick up into the air gives the seedling roots a little extra oxygen while they’re small.
Example of cannabis seedlings growing in coco coir, about to get seedling-strength nutrient water! If these seedlings were in soil, I would be giving just plain, pH’ed water for the first few weeks.
Water immediately with 1-2 cups of water. Give 1 cup in a bigger than 3-gallon container, especially if it still feels wet from when you watered before. Give 2 cups water in a smaller container or drier medium. The reason you would give more in a smaller container (which seems sort of a paradox) is because the moist medium will dry much faster in a smaller container, while a big container will hold onto the water for longer. You’re just trying to avoid putting your seedlings in a situation where their roots stay very wet for more than a day or two, but you also want to avoid letting them ever dry out.
- Coco – water with seedling-strength nutrients, and make sure to pH your water to 5.5-6.5 right before giving it to your plants. Coco does not naturally contain any nutrients, so if you don’t give some from the beginning in the water, each plant only has what was contained in the shell and Rapid Rooter! Seedlings in coco coir grow far faster if you start them off with seedling-strength nutrients from the beginning!
- Soil – water with plain, pH’ed water at 6-7 pH, no nutrients, for the first 3 weeks or so – your plants will be able to live off the nutrients in the soil, and adding extra might be overload and nutrient burn them.
- Hydro – install into your system by putting the Rapid Rooter into your net pot. Learn more about growing hydro. Typically you either water your plants every day until the roots reach the reservoir, or you have a drip feed which waters the plants for you.
How to Water Seedlings in the Beginning
- Don’t water plants until soil or coco is dry up to first knuckle. You want to water your plants every 2-3 days if possible.
- If the growing medium feels dry again within 1 day, give double the amount of water the next time. Otherwise give the same amount again.
- Repeat, until you can give enough water to at least a little runoff, and have it dry in a few days.
- Try to maintain a schedule with you watering your plants every 2-3 days.
- If your growing medium takes longer than 3 days for the top inch to dry, it means the soil is staying wet too long, and plant roots aren’t getting enough oxygen. It also puts your plants at risk of getting fungus gnats. Try giving less water at a time until plant is drinking more. It’s possible you may have a problem with drainage in your medium (what is good soil?) or for some reason water is having a hard time coming out the bottom of the container, for example if there no drainage holes. You also should always make sure to remove runoff water instead of letting the plant sit in it.
- If the medium is drying in less than 2 days, it means you need to give more water to the plant at a time, or possibly transplant to a bigger container if the plant has outgrown its old one.
- Complete guide: How to water cannabis plants perfectly every time
- If seedlings are droopy, how can I tell if it’s caused by overwatering or underwatering?
If your seeds still aren’t sprouting and growing properly, consider the following factors.
If there’s no germination at all…
- Temperature may be too hot or cold – aim for 75-80°F
- Too wet – seeds and seedling roots should always be moist, but should not be soaking wet
- Too dry – if a root dries out the seedling can die!
- Bad seeds – It might not be you, it could be the seeds themselves! Even if you purchase from a good breeder, sometimes you still get duds. How can I tell if seeds are viable?
If seeds sprout, but then stop growing…
- Temperature is too hot or cold – aim for 73-78°F
- Too wet – new seedlings don’t like “wet feet” so make sure your Rapid Rooter or growing medium nevers looks shiny or muddy, as that means there’s too much water! For this reason, it’s also usually recommended to avoid using a humidity dome with seedlings unless your air is dry. Although clones love humidity domes (they need water from the air because they don’t have any roots to get water), seedlings like it a little more dry or roots tend to get mushy.
- Too dry – less common unless you live in a very dry area, but sometimes your medium dries out too fast if you’ve got a heavy-drinking, fast-growing seedling!
- Too much light – if the seedlings get blasted with high levels of light right away, it can shock them. They may need some time to adjust to higher light levels. Simply starting your grow light a little further away that normal is usually enough.Think sunny window at first, and start ramping up after a week of healthy growth.
- Not enough light – if seedlings are growing long and stretchy without growing new sets of leaves, it means it wants more light.
- No light for more than a day – if the sprouted seed doesn’t get light within 24 hours after sprouting, it may die. Once seeds are sprouted, get them in a Rapid Rooter and under at least some amount of light as soon as possible!
- Roots damaged – If somehow your roots got damaged, it can sometimes stop the seedling from growing
Unfortunately sometimes you will never know why certain seeds just don’t thrive! It’s all part of nature 🙂