Germinating Cannabis Seeds For Hydroponics


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Starting seeds for hydroponics doesn't have to be difficult. In fact, it's really easy! Learn how to do it in 10 minutes with this Epic Gardening tutorial! The most in-depth and detailed guide on how to Germinate Cannabis Seeds. Learn 5 different methods. Decide what will work for you. Simple and easy.

A Simple Guide to Starting Seeds for Hydroponics

You’re not alone — when I first started gardening, I was a soil gardener.

Starting seeds for hydroponics systems was unknown to me until I started to build deep water culture and ebb and flow systems. Once I built those, I had to learn how to start seeds hydroponically.

One of the main benefits of hydroponics is the absolute control you have over your growing environment. Knowing that, I didn’t want to germinate seeds in soil and then transplant into a my hydroponic system, adding a bunch of dirt to the system.

There had to be another way.

Here are just a few reasons why you want to start seeds in a hydroponic system as opposed to soil:

  • Much cleaner than starting seeds in soil
  • Seedlings grow faster after germination
  • Easy to transplant into a larger hydroponic system

That second reason is a cool one. As soon as your tap root pops out, a hydroponic system is going to help it grow faster than soil and prevent it from becoming rootbound.

Step 1: Get Your Materials

You don’t need much to get started. If you build your cloner yourself, the rest of the materials will cost you under $50 bucks and will last you for quite a while. If you decide to go with a store-bought cloner, it’ll bump up the cost a bit but you’ll also be getting a much higher quality product.

Seed Starting Materials List

    – You can either build your own or use something like the Clone King and starter plugs (#3 below)
  1. Seeds – find at your local nursery if possible, or buy many places online. A personal favorite of mine is

Step 2: Fill The Cloner With Water

Fairly simple step here. All you need to do is fill up your reservoir to just under where your net pots sit. Don’t worry about pHing your water or using reverse osmosis right now – standard tap water will be fine.

Step 3: Set Up the Air Pump

Place the air stone in the reservoir and connect the tubing. Connect the other side to the air pump and plug it in. You should see some beautiful bubbles start to come out of the air stone. These bubbles are what will keep the roots of your seeds moist and stimulate growth.

Step 4: Place Starter Plugs and Seeds

Soak each starter plug in some water and then place it in a net pot. The moisture will help the seeds germinate.

Drop 2-3 seeds in each starter plug. We use more than 1 seed because not all seeds will germinate and we want to make sure that every starter plug has a sprouted seed – otherwise we’ll have to replant!

Step 5: Maintenance

This system is very easy to maintain as your seeds sprout.

If you want, you can place a transparent cover over the top to keep in some moisture and increase the temperature of the system, but it’s not necessary.

Make sure to moisten the starter plugs with a few sprays from a spray bottle every day so your seeds have enough moisture to sprout.

When your seeds sprout, clip off all but the strongest seedling from each starter plug.

That’s it! Your seeds should sprout in 3-5 days for most plants and you’ll be ready to start growing some truly epic plants in your hydroponic system in no time!

Video Guide

If you’re more of a visual learner, I have a three part video series from my YouTube channel​ that goes into the entire setup in detail.

Part One: The Basic Setup

This is the visual version of the blog post. Helpful if you just need to SEE to learn (like me).​

Part Two: Making Sure Seeds Germinate

This part of the series talks about some of the maintenance and troubleshooting you might run into when starting seeds, including the infamous “why do they keep falling over” problem that a lot of beginners run into.​

Part Three: pH Water and Add Nutrients

This part of the series talks about the need to pH and add nutrients to your reservoir after the seeds have germinated. Because they feed off of their seed leaves at the start of their life, you can get away with not doing this until the seeds germinate.

By the way, I’m using the Bluelab pH Pen​ to fill all of my pH needs. It’s awesome!

How to Germinate Cannabis Seeds with Guaranteed Success!

If you are looking for different ways to germinate your cannabis seeds.

You have come to the right place.

In this guide you will learn all you need for success at sprouting your seeds.

So you will get the most genetic potential out of your growing marijuana.

Follow along, and there may be some ways to bigger yields, higher THC count and healthy plants.

See also  Bulk Weed Seeds

Marijuana seedlings sprouting.

The germination process takes around 3 to 7 days until they become marijuana seedlings.

With so many different ways to germinate marijuana seeds.

I have included as many as I could in this guide as the way to help you in starting a new life!

Start to Germinate your Cannabis Seeds

The best way I have found is to soak your seeds to give them a head start a speed up the process.

  • Grab a glass and fill it with room temperature reverse osmosis water or plain old filtered tap water.
  • Put your marijuana seeds into a glass of water.
  • Then place the glass in complete darkness either in a cupboard or enclosed container.

Grow Tip: If you want to germinate your seeds fast! Just add Hydrogen Peroxide 1 ml to every 100 ml of water.

In this process, the seeds absorb the water through the perianth layer or outer shell.

This process may take up to 24 hours.

After about 14 hours or more the seeds should now have sunk to the bottom.

They have now absorbed the required amount water to start the germination process.

When the seeds are still floating, then they may be bad seeds and might not be not viable.

If your marijuana seeds are still floating after 24 hours give the seeds a light tap to see if they sink. If they do, you got a keeper!

Now they are ready for the next step transferring into a medium or paper towel.

Paper Towel Method

The paper towel method is the most popular and easiest ways to ensure your seeds sprout.

When germinating marijuana seeds in paper towel.

  • Fold your paper towel into a rectangle or square and soak with reverse osmosis water or distilled water of your choice.
  • Place your fresh waterlogged seeds from the beginning process into the paper towel evenly spaced out
  • Fold the paper towel and place inside a zip lock bag or between two plates.
  • Place the zip lock bag or on top of the fridge with a regular dish towel over it or in a warm dark area.
  • Wait for 24 hours or up to 36 hours and make sure to check the paper towel to make sure it has not dried up.

The seeds should now have sprouted.

Your seeds are now ready for their starter growing medium

Use a pair of micro tweezers to gently grab the top of the seeds to transplant.

Jiffy or Coco Coir Pellet Method

This method is one of the best ways to germinate your marijuana seeds. It has a great advantage over some other methods.

A lot of growers experienced great germination results from these little inexpensive pellets.

They come highly recommended for beginners.

  • Fill a container with reverse osmosis water or filtered tap water ph balanced water to about half way. A big bowl works just fine
  • Place the pellets into the water
  • Wait until they expand and full of water
  • Optional if you deem it necessary: Gently squeeze the jiffy pot to release some water. (DO NOT Squish) be gentle
  • Squeeze the pellet to halfway closed at the bottom.

We do this so the seed does not fall into the lower part of the medium that would be tragic.

There is a hole in the top of the pellet this is where we will place the seed next. So the seed does not fall into the bottom of the medium that would be tragic.

  • Take your recently soaked cannabis seed and place it into the hole on top of the Jiffy Pot
  • Brush over with the rest of the peat or coco coir on top do not push down hard
  • Place into a humidity dome

Once your seed starts to sprout leave in the dome and releases the lid so they can breathe at least twice a day.

Make sure the temperature is between 75 and 80 degrees Fahrenheit or 23 to 27 degrees Celsius.

Humidity is around 70 to 80 percent.

The cannabis seedling should be at least 6-8 inches high before transplanting into a growing medium.

Soil Method

This method is relatively easy.

It’s just mixing soil and putting it into a sanitized container preferably not too large.

You do not place this in a humidity dome, just only make one with plastic wrap.

One other obvious note is that this method will be the only medium you can continue in.

  • Use your container and fill it with soil to just below the top
  • Dump into either a bigger shopping bag or into a bin
  • Slowly pour a small amount of reverse osmosis water over the soil. You just want the soil to be damp to the touch and to spring back after squeezing if it’s too moist add some more dry soil.
  • Mix with hands ( make sure you wash your hands!) or use some disposable vinyl gloves to keep thing sanitary for these new seeds!
  • Add the mixed soil to the sanitized container
  • With a finger and in the middle make an indent or hole about a half a centimeter or 2/8 of an inch deep
  • Take your seed that has sprouted by using a pair of micro tweezers. Gently grab the top to the seed and careful not to touch the tap root at all.
  • Next place the seed into the hole taproot facing down and lightly cover with some soil
  • If using the seed that has just sunk to the bottom of the glass, place it into the hole and cover with soil
  • Gently drop some water on the new surface, not too much.
  • Take some plastic wrap and place over the top of the container with some gap between the soil and the top
  • Place under a light of your choice
  • Your cannabis seed should sprout in 2-7 days.
See also  How Often To Water Marijuana Seeds

A short video on using soil for germination,

Rockwool Method

This method works extremely well with hydroponic systems which include coco coir one of my favorite mediums and Hydroton clay pebbles.

If done right, you can obtain some massive roots systems which can then leads to huge buds!

I recommend wearing a cheap mask from the hardware store, some disposable vinyl gloves when handling rock wool.

Also use a chopstick or small screw driver to place a hole in the under side of the rock wool cube.

  • Pour reverse osmosis water ph balanced to 5.5 into a container that can hold the rock wool cubes.
  • I use 1.5 inch cubes
  • Place the rock wool cubes into the water and soak them until thoroughly drenched, at least a couple hours to soak.
  • Remove them from the water
  • Take a pair of scissor and place them in the hole of the top of the cube and slice a corner so it splits.
  • You should now be able to gently open it up
  • Take your seed that has sprouted by using a pair of micro tweezers. Gently grab the top to the seed and careful not to touch the tap root at all.
  • Place the seed into the hole taproot facing down and gently cover with some of the rock wool fiber.
  • Use an elastic band to close the cube and make sure it is a little tight to seal the seedling in place.
  • Put the cube in a humidity dome

Once your seed starts to sprout leave in the dome and releases the lid so they can breathe at least twice a day.

Make sure the temperature is between 75 and 80 degrees Fahrenheit or 23 to 27 degrees Celsius. With the humidity is around 70 to 80 percent.

The seedling should be at least 2-3 inches high before transplanting into a growing medium.

A short video on using rock wool for germination

Rapid Rooter Method

This method is the recommended alternative to rock wool method.

The “plugs” can be used in hydroponics setups the same way as Rockwool cubes.

Except it is possible to use these for soil method as well. Although not widely used as the peat pellets are cheaper and easier available.

  • Pour reverse osmosis water ph balanced into a container that can hold the Rapid Rooter plugs
  • Remove the “plugs” and let some of the water drain off
  • If using a soaked marijuana seed. Place it into the hole on the top of the plug and move some of the fiber across the top and place into humidity dome
  • Take your seed that has sprouted by using a pair of micro tweezers. Gently grab the top to the seed and careful not to touch the tap root at all.
  • Put the seed into the hole tap root facing down and gently cover with some of the Rapid Rooter fiber.
  • Place into a humidity dome

Once your seed starts to sprout leave in the dome and releases the lid so they can breathe at least twice a day.

Make sure the temperature is between 75 and 80 degrees Fahrenheit or 23 to 27 degrees Celsius. Have the humidity is around 70 to 80 percent.

The marijuana seedling should be at least 6-8 inches high before transplanting into a growing medium.

A short video on using rapid rooters for germination

Gear for Germinating

Below you will find a list of supplies you may require. All items are not that expensive, and many will get multiple uses.

Not all is needed depending on the method you choose

Cannabis Seeds can be purchased from a reputable Seed House online and or online suppliers.

Some retail stores in some parts of the world where it is either, legal or used medically.

I do not recommend using seeds that were from a recent purchase of Buds. As these seeds tend to be hermaphrodite and have poor germination. The perianth layer (outer shell) has damage due to the drying and process.


Soil this is one of many mediums. Marijuana seeds can be planted straight into or used as a medium to transplant.

I recommend one that is not time released nutrients.

Free of excess nutrient N-P-K and source one that is good overall and organic.

The most notable and easy to obtain almost everywhere is PROMIX.

Some other organic brands of soil are FOX FARMS (ocean forest ) and (happy frog) and Roots Organic or any other local brand.

See also  Marijuana Seed Pods

You will also require a container to store the soil. I like the air pots, what I do is make my own out of Landscape fabric.

But remember any pot under 6-inch diameter will do. Even plastic cups work ( and they are cheap for the amount)

Jiffy Pellets(Peat Pellets) or Coco Coir Pellets. The pellets are filled with either peat or coco coir(coconut husks). And surround by a thin air flowing fabric.

Jiffies come in pellet form and to expand them you just soak them in water.

I highly recommend these for transplanting to soil or coco coir medium.

Organic / In-Organic Mediums

Rock wool Cubes are great inexpensive starter medium and come in many sizes.

Rock wool has many benefits but it does come at a cost to the environment.

It does this by being inert according to Wikipedia and not degrading and remain dormant in landfills.

On the other side of the coin, some would argue it is good for landfills. By providing air pockets in the landfill to assist on it breaking down.

I will show this method as some people do use this method with great success.

It has known that if done properly can grow massive plants with an enormous root system.

Also, they are resistant to mold and hold moisture extremely well. Rockwool is suitable for hydroponic growing.

There is an alternative to using rockwool if you are more conscious of the environment and looking for a bio-degradable solution they are the following.

Rapid Rooter Plugs are from a company called General Hydroponics. The plugs work by providing the balance of water to air. Which prevents rot and promotes root growth which is essential for your young seedlings starting out.

Another version is also out called Root Riot.

The “plugs” are made up of composted organic matter held together by plant-derived polymers. The Rapid Rooter plugs could be transplanted to all growing mediums.


Light it is required for all plant growth stages except the very beginning. Some use just sunlight or a standard light bulb. These tend to get mediocre results.

There are all types of bulbs out there from your standard grow lights (HID) or LED to CFL and fluorescent.

When using, your grow lights do not place your lights to close to the new seedlings. The light will burn the leaves and kill the plant.

CFL Bulbs I recommend are full spectrum, at least, 5000K to 5800K with 45 watts or more. The bulbs can be obtained either online or at your nearest hardware store.

T5, T8, T12=(size of a bulb) high-intensity UVA UVB fluorescents or full spectrum bulbs.

The regular fluorescent bulbs work as well. You will need two different types of bulbs.

Cool White or a spectrum of 6500K and a Warm White(Soft White ) 2500k-3500k range.

Some growers use the UVA/UVB lights during the last two weeks of the growing cycle, and they say it can increase THC count by 5%

Green Lightbulb it can be either a CFL or regular incandescent bulb. This light is superb for the overall general grow. The green light does not interrupt the plant’s light cycle. Which is key to growth and overall well-being of the plant.

Additional Items

Humidity Domes are essential in keeping the humidity high for your new marijuana seedlings. Promoting healthy growth at the start is important for your marijuana flowers.

They are inexpensive, come in various sizes. Humidity domes can be used over and over again with a proper sanitation and cleaning.

RO (reverse osmosis) water or distilled water.

I do not recommend using tap water, even though it’s right there somewhat free.

There are many contaminants in the water that will affect the new seeds growth. Either excessive ph or calcium fluoride just to name a few.

Paper Towel (3 sheets ) and a Ziplock bag this is pretty self-explanatory

Portable temperature and humidity meter. These can be purchased for around ten dollars or online at Amazon

Optional Hydrogen peroxide. A small amount of Hydrogen peroxide adds to the cup of water for germinating.

After germinating cannabis seeds

Now for the time after you have planted your marijuana seeds and are facing the challenges after germination.

There will be many obstacles.

You are not home free from here. You have to deal with:

  • Possible mold
  • Spider mites
  • Small flies
  • Over watering
  • Neglect
  • Power outages
  • The possibilities are endless.

But in all seriousness, it should be no problem from here.

By following the simple steps listed above it should guarantee you success. The next time you germinate those marijuana seeds.

In the next month or so depending on the size you want, you can start to focus on transplanting.

This guide, I have touched on virtually all methods with some added awareness to different steps.

Let me know in the comment your preferred method, and how your plants are doing.

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