Germinating Weed Seeds In Rapid Rooters

I don't have good luck with germinating seeds or keeping them alive long enough to grow out. Most of my failures have come in the first two weeks so I am… This marijuana germination tutorial is different. Get exact steps from beginning to end (with pictures!) so your germination goes fast and seedlings start strong! Weed seeds germination can be easy and fun. Learn how to successfully grow your own cannabis plant with our step by step guide.

Starting seeds in Rapid Rooters?

I don’t have good luck with germinating seeds or keeping them alive long enough to grow out. Most of my failures have come in the first two weeks so I am modifying what I normally do in an attempt to get better results.

My new plan is to use rapid rooters and just place the seed in them, then place the RR in a seedling tray, put 1/4″ of water in the bottom of the tray, put on a humidity dome and put all of it in the dark.

The temp in my closest varies from about 80-85*F and the relative humidity is 66% without the humidity dome. The RH jumps to 85% RH with the dome on.

Is 85*f and 85% RH too high and could this cause fungus problems? Is 66% high enough given the fact they are sitting in a 1/4″ of water?

chuck estevez
Well-Known Member

I soak my seed in a glass for 12 hrs, drop into rooter,put little piece of rooter over hole. put nxt to window, at night, under cfl

Well-Known Member

Sounds like a recipe for cooking rotten seeds.

Don’t use a dome with seedlings, 66% is fine, so is 40. Seeds and seedlings do not require high air humidity level. And don’t put the rapid rooters in a layer of water. Instead add a layer of perlite or hydroton, put the rapid roots on those and water them. Try to keep the temp below 80.

I too soak seeds in (warm yet cooling down) water for 12-24 hours before planting them.

And place them under light.

Well-Known Member

And don’t put the rapid rooters in a layer of water. Instead add a layer of perlite or hydroton, put the rapid roots on those and water them.

That’s a brilliant idea! I will do just that.

I read two different versions. Some same put the RR in the dark to germinate and others say put them under light. Even the Rapid Rooter tray instructions say to place them in the dark to germinate.

Why is light so important when the seed is under cover anyway?

Well-Known Member

Even though your temps are 80-85f in the space the wet RR will be colder and it will likely fluctuate. Putting light (not too strong, I use T8 ) above it helps keeps the temps in the RR stable. But besides that, if you’re already have a hard time germinating, they will likely not all pop the same day and seedling that grow up in the dark become stretchy and lanky (searching for light) fast.

Soaking them addresses both of those issues. If germination fails from improper environmental settings it’s usually shortly before cracking open (too much water, not enough oxygen, and/or too cold/warm) or when it just cracked. The longer that takes, the riskier it gets and the more important it becomes that the environment remain stable. Ideally you measure the inside of the RR for a complete day.

Well-Known Member

Not only that but you can try for yourself an easy experiment. I had to do it for class but we did Pinto beans and did various hypothesis and tests. Anyway, one of the hypothesis I tested was light vs no light and they were in the same enviorment, one was just in a box without light. The roots were MUCH more developed on the beans in the light. this is them sitting in a moist paper towel inside of a plastic Baggie for 7 days. Soaking them vs unsoaked was also noticible but strangely light outside vs light inside didn’t have too much of a difference. and my outside temps were 90F~ while the inside was 75~

Well-Known Member

Not only that but you can try for yourself an easy experiment. I had to do it for class but we did Pinto beans and did various hypothesis and tests. Anyway, one of the hypothesis I tested was light vs no light and they were in the same enviorment, one was just in a box without light. The roots were MUCH more developed on the beans in the light. this is them sitting in a moist paper towel inside of a plastic Baggie for 7 days. Soaking them vs unsoaked was also noticible but strangely light outside vs light inside didn’t have too much of a difference. and my outside temps were 90F~ while the inside was 75~

My first grow was a fist fight that I lost. I was smart enough to grow more seed than I needed and finally figured out what I needed to know enough to grow and harvest a few plants. I feel like if I can get my plants to live to two weeks old, I think I’ll have a good chance at finishing them.

I’m been trying to practice on bag seed and not having any luck germinating. I’ve order some expensive seeds and ready to try to germinate them but nervous they won’t germinate.

I’ve tried the paper towel method a couple of different ways and that bag seed didn’t crack. It could be just bad old seed but I’m not sure it’s not at least partially my method.

I’m thinking as soon as the seeds break the surface in the rooter, to plant them in a cup and move them to the tent under CFL’s at 12/12. The rooter won’t sit in the seedling tray for more than a day after they break the surface and won’t grow roots out of the rooter before they are moved.

First, I have to get them to germinate without growing fungus. Sativied’s idea of putting that rooter on top of a bit of perlite wicks the moisture up without saturating the rooter is a great idea. I am testing that right now to see what kind of moisture the rooter will hold and for how long while I wait for my seeds to arrive.

If you guys say put lights over the rapid rooters to germinate, I’ll do it, but it seems counter intuitive to me if seeds need dark to crack.

Fail-Proof Cannabis Germination Method in Soil or Coco

We have a cannabis seedling germination page that includes 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.

Turn your cannabis seeds…

This step-by-step tutorial will teach you how to germinate seeds and provide basic seedling care

Soon you’ll have healthy cannabis plants to admire

Supplies Needed

1.) Get Cannabis Seeds

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.

Here’s a picture showing several healthy and viable cannabis seeds

2.) Prepare Your Soil or Coco Containers

Before you start germinating your seeds, set up your soil or coco. It will still be a few days until your seedlings arrive, but you want to have everything ready before the seedlings need to be planted.

Get your containers ready before you start germinating

3.) Germination

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.

See also  What To Do With Leftover Weed 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 put that between two plates. The purpose of the plates is to prevent the seeds from drying out. Don’t let any part of a paper towel hang out the edges or it will wick away all the moisture and dry out. Keep everything totally contained between the plates.

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. Make sure now paper towel is sticking out the sides.


  1. 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.
  2. They should germinate in 1-4 days, though some seeds can take 7 days or longer (especially older and smaller seeds).
  3. Keep them warm if possible. Seeds 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.

Seeds often germinate at different rates even if they get the exact same conditions

4.) Place Germinated Seed in a Rapid Rooter

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.

Rapid Rooters are nice, but not necessary

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 their texture causes most seeds to stay in place and not “fall down” further into the hole once you’ve got the Rapid Rooter closed.

5.) Water the seedling in the Rapid Rooter until you see a root come out bottom, 1-2 days.

Make sure to always keep the Rapid Rooter moist but not soaking wet and give plain 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 if possible because a tiny tug in the wrong direction can pull the seedling out of the plug and break off the taproot.

Try to let the seedlings break free if possible. But if you have a seedling that’s stuck in a shell after a day or two, and doesn’t seem to be getting any better, you need to go in and help.

I’ve found that pointy tweezers are perfect to pry open a shell that’s stuck. Just close the tweezer, stick it inside between the shell halves, and let it slowly open to pull the shell apart without you ever touching the seedling.

Sometimes a “film” from inside the shell gets stuck on the leaves. If that happens, try putting a drop of water on the film a few times a day to soften it. If the seedling doesn’t push it off on its own, hold the stem between your fingers (so it doesn’t pull at the root) and use tweezers to gently tug at the membrane and release the leaves.

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 filtered light. A CFL or LED light 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 Home

You are about to water your seedlings for the first time, so prepare your water now.

  • Coco – Prepare water with seedling-strength nutrients, and make sure to pH your water to 5.5-6.5 right before giving it to plants. Unlike soil, coco does not naturally contain any nutrients so you must provide nutrients in the water from the first watering.
  • Soil – Prepare plain water at 6-7 pH. You don’t need to add nutrients for the first 3 weeks or so because your plants will live off what’s in the soil. Adding extra nutrients at this point might overload and burn the seedlings.

Now that your water is ready, dig a hole that’s a little smaller than the Rapid Rooter, and place your seedling plug inside. The idea is to let the Rapid Rooter stick up above the soil a little to help the roots get more oxygen. It’s okay if the plug goes in flat with the soil, but don’t bury the stem as that can cause stem rot in some cases. Even if you’ve got a tall seedling, you usually won’t notice the extra length once the plant is bigger.

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Gently pack the nearby soil/coco to hold the Rapid Rooter in place so the seedling is stable.

Your seedlings get a little extra oxygen if you let the Rapid Rooter stick up into the air slightly as opposed to burying it.

Example of cannabis seedlings growing in coco coir, about to get seedling-strength nutrient water. If they were in soil, I would give plain water for the first few weeks.

Water immediately in a small circle around your seedling. For most grow mediums and containers above 1 gallon, you can give 2 cups (500 ml) of water immediately without overloading your seedling. If the grow medium feels moist (for example coco that was recently re-hydrated), give 1 cup (250ml) of water this first watering.

Give 2 cups (500 ml) water in a circle around the seedling. If the grow medium is already wet, give just 1 cup (250 ml)

How to Water Seedlings in the Beginning

Two Main Goals

  • Seedling roots never dry out (most important)
  • Seedling roots aren’t staying soaking wet (roots need oxygen)

Seedlings “drown” and die due to lack of oxygen if they get too much water too often. To avoid this, try to provide an amount of water that lets you water seedlings every few days. Avoid giving so much water that the seedling roots are in a super wet grow medium for days as this causes “damping off” and root problems. Some grow styles like high-frequency fertigation call for watering more frequently. Just remember that the more often you water your plants, the less water you should give at a time. Also, keep in mind that a smaller container tends to dry out fast while a bigger container holds onto the water for longer

Try to maintain a schedule that lets you water your plants every few days without them looking droopy

  • Water in a small circle around the base of the plant at first
  • If the growing medium feels dry within 1 day, give more water next time. Otherwise, give the same amount again next time you water
  • Repeat, until you can give enough water to get at least a little runoff, and have it dry in a few days

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 current one.

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 the plant is drinking more. It’s possible you may have a problem with drainage in your medium ( what is good soil? ) or there are no drainage holes so extra water can’t come out the bottom of the container. Always remove any runoff water instead of letting the plant sit in it.

More seedling resources

Some growers like to put seedlings in solo cups and then into their final container. When done right this can increase the rate of growth by providing more oxygen to the plant’s roots. If you go that route, I recommend paper cups as they’re not as bad for the environment.

Autopsy: Why Aren’t My Marijuana Seeds Sprouting?

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 75-80°F
  • Too wet – new seedlings don’t like “wet feet” so make sure your Rapid Rooter or growing medium never 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 drier 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 than 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. But if you follow this tutorial you will get the best results possible.

How to Germinate Weed Seeds: Three Easy Methods

People have been growing cannabis for more than 10.000 years, and the best thing about it is that it’s very adaptable to different environmental conditions.

Before we go over why that’s good and what you need to know about the process of growing marijuana, let’s familiarize you with some basic information.

Cannabis plants are divided into male and female counterparts and both of them produce flowers. Each sex has its own characteristics, and it is important to know them if you want to grow weed since they can affect the outcome of your plant’s growth.

The roots of this plant make a dense net, and they can go up to six feet in depth. When you look at the total mass of the plant, roots are only 10% of it, which means that they have low power of suction.

Female cannabis plants have stronger roots than male ones. It’s because male plants finish vegetation faster. Female plants keep adding nutrition to their seeds until they grow which means feminine seeds need more food and water to finish the process. That process makes their root system stronger.

First, Let’s Set Everything Up

Are you familiar with the term ‘germination’?

Germination is ‘’the process of seed starting to grow or the act of causing a seed to start growing.’’ So in essence, we’re trying to help kick start the growth process of your very own cannabis plant.

Before you start with your germination process, there are some things you need to prepare and learn first. Like any other plant, cannabis needs certain conditions in order to grow such as:

  • Temperature
  • Water
  • Light, etc.
See also  Best Containers For Weed Seeds When Starting

Minimal germination temperature is 1°C – 2°C, while the optimum is around 30°C. Cannabis can grow in low temperatures too – as I said, they’re pretty adaptable. But still, you should do your best to maintain the optimum temperature if you want to be sure the germination process is successful.

This plant needs a lot of water, so make sure you have enough of it. Also, you need to be careful about lighting. If you lower sunlight, the plant will germinate faster, but it will be shorter and the leaves may change their shape.

Lastly, there are some technical things you need to be careful about. Hygiene is number one. It’s always important, of course, but especially if you want to plant cannabis seeds. So, take good care of your tools, your hands, the place where you plant it, etc.

If you’re a smoker, for instance, don’t even think about touching the plant if you don’t use antibacterial soap first. Nicotine can be poisonous to cannabis plants, don’t forget that.

There is one tip we can give you — always have rubbing alcohol by your side. So, whenever you want to cut, see or touch your plant, spray the alcohol on your hands, scissors, tweezers, etc. You can never be too careful!

How to Grow Weed Indoors for Beginners [Follow-Along Guide]

Germination With Paper Towels

One of the easiest methods is definitely this one, where you use paper towels. There are three things you’ll need: cannabis seeds – of course, paper towels, and clean plates. You don’t have to invest a lot, the cheapest paper towels will do a great job also.

Although this method is simple, it can be risky. You can easily damage the roots while you move the seeds, or the paper could lose its moisture, killing the seeds in the process. But if you are careful enough, everything should go according to plan.

Without further ado, let’s give you a quick step by step guide how to germinate weeds using paper towels:

  1. Soak the paper towels in water (preferably distilled). You should soak them well, but on the other hand, be careful that they aren’t dripping water.
  2. Take a plate and place two paper towels on it. Lay the seeds out (spaced well enough so that they aren’t close to one another), and then cover them with two other towels.
  3. Use another plate to cover everything. This way you ensure that the moisture is well locked in.
  4. Keep everything in the room at optimal temperature (30°C) and don’t forget to check the seeds to see whether they have sprouted. If you realize they are drying out, add a little bit of water.
  5. Be patient! This step is very important. Usually, the seeds will sprout within 24 hours to four days, but it can take up to a week.

There you go! Your germination process in just five steps. No wonder this is considered to be so quick and easy.

Germination With A Glass of Water

This is the process that involves only one single glass and lukewarm water. Simple, right? Well, it definitely isn’t hard and it doesn’t require a lot of effort, but there is a higher chance that this method won’t be as successful as the first paper towel method.

First of all, the best seeds to use with this method are old and hard seeds. Place them in the glass overnight, but no longer than 32 hours.

When you place them in the glass, you’ll notice that the seeds will keep floating. Don’t worry, in a few hours, they will sink to the bottom. Our recommendation is to use transparent containers since that way you will be able to see the white tips of roots break out.

As we already mentioned, there is a possibility this method won’t work. If that happens, take out the seeds and lay them out in a warm place. After that, the best thing you can do is use the paper towel method to continue the germination process.

Hydroponic Weed Growing Guide: Grow Cannabis at Home (Step by Step)

Germination Using Medium

Cannabis is a plant that has grown on its own for centuries. Their seeds are sprouted in soil and they emerge as the roots start to grow down. That being said, germination in soil medium is the closest to their natural growth.

If you decide to go with this method, there is no need to worry about your seeds. There aren’t any chances to damage them while being transplanted. Usually, transplanting your seeds can cause damage since they have to adjust to their new surroundings. With this method, however, the seeds will start adjusting to the environment in no time.

The process is quite easy. Dig a hole (the size of a fingernail), and place the seed. Cover it and after that add a little bit of water to moisten the surface. Be careful about that, if you add too much water it could kill the seeds. Balance is key. We recommend you to buy a spray bottle when you want to add water to the plant to prevent overwatering the seeds.

There is one tricky part that you have to be careful about. If you want to go with this method, the humidity level in the room should be 50% – 70%, and you should always maintain it at that level.

You will have to wait for three to seven days to see results when using this method. After that, the seeds should start emerging.

Starter Cubes: The Easiest Germination Method

Germination using some type of growth medium is not hard, but it can be much easier thanks to starter cubes you can easily buy and use. There are different types, but they all have the same purpose — to make the process as easy and successful as possible.

They’re made out of a sponge-like material made of organic matter with nutrients and serve as a natural grow plug for seedlings. They’re user-friendly and you always get easy-to-follow instructions when you buy them.

They all work in the same way. Just place the seed in one of the cubes and add water. These cubes already have holes inside, which means that you don’t have to dig and that your seedlings get the best conditions possible for germination.

There are different types of starter cubes you should know about:

  • Rapid Rooters – Using these, you don’t need any preparation. Just take them out of the package and follow the instructions. Each package usually has enough plugs that can accommodate 50 seeds at a time. *(image from amazon)
  • Rapid Rooter Trays – These are basically rapid rooters that are made into cubes and packaged into a tray. They can stand on their own thanks to their flat bottom. *(image from amazon)
  • Rockwool Cubes – Also called Stonewool cubes, these are made of basalt and chalk spun into matter similar to cotton candy. Unlike rapid rooters, these cubes may not have holes, so you’ll have to dig them by yourself.

With any of the above starter cubes, there’s little chance for error. If you’re a beginner, we highly recommend you try starting out with them first. Once you gain experience, you can try out other methods.

To Conclude…

As you can see, you don’t need any special knowledge to germinate marijuana seeds. Arm yourself with patience, practice and good tools and the results will amaze you.

We encourage you to try one of these germination methods since they do not require a lot of effort and investment.