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
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 paper plates (or regular plates) so that they don't dry out.
- Check on your seeds every 12 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 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.
These seedlings were sprouted using the paper towel method!
The Rapid Rooter should be cut open lengthwise
Gently place the germinated seed inside, root down
Most seedling plugs will go back into place easily, and you'll barely be able to tell it's been opened 🙂
4.) Prepare Your Soil or Coco
While that's happening, set up your soil or coco if you haven't already, and give it a good watering. This will make sure everything is completely wet (it can be hard to properly water soil or especially coco if it's very dry unless the whole medium gets saturated first), but it will still be a few days until your seedlings arrive so it will have time to dry out.
Right after putting your sprouted seed in the Rapid Rooter, water your container of soil or water. This gives 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!
You aren't going to 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 down there.
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 occasionally you actually see the seedling push the shell above ground.
When this happens the shell usually falls off on its own as the seedling grows! But if it's there for more than a day or two, you should gently remove it so your leaves can be free 🙂
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 flourescent (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 well for me 🙂
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.
How to Water Seedlings in the Beginning
- Don't water plants until soil or coco is dry up to first knuckle.
- If it 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 watering 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 hte 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 stay 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! 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 🙂