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How to Germinate Cannabis Seeds

Updated July 22, 2022

People have been growing cannabis plants for thousands of years. If you live in an area where it is legal to possess and grow cannabis, then you can grow the plants. There are two main methods of growing cannabis, from seeds or cuttings. If you choose to grow from seeds, the first step to the process will be to germinate the seeds. The process can be more intuitive than you may realize at first.

How Long It Takes

Before you start germinating cannabis seeds, make sure you understand how long this task will take. Most cannabis seeds will germinate within between three and seven days. Some other types, however, may take longer, with some taking up to 10 or 15 days.

How to Tell When Germination Is Complete

Once the seeds germinate, they will have small white taproots that come out of one end. This is a sign that you are ready to plant the seeds.

The Basics to Control

Keep in mind that for the cannabis seeds to germinate, you will need to provide it with the proper temperature light and humidity or moisture. You should be able to control these factors enough to germinate seeds without any special equipment. Even so, investing in monitoring and control equipment for these factors can increase the chances of your seeds growing.

Choose Your Seeds

Before you can germinate your cannabis seeds, you will have to select the seeds that you want to grow. There are over 100 cannabinoids in cannabis, so you can choose a strain that has substantial amounts of the ones you want. Of these, you will be most interested in CBD and THC. CBD is non-psychoactive and associated with most of the benefits of cannabis, such as relief from pain and nausea. THC is psychoactive and can enhance the effects of CBD when the two are used together, something known as the entourage effect.

In addition to choosing the seeds based on the content of cannabinoids like THC and CBD, you should also think about the aroma, and whether you prefer Sativa, Indica, or Ruderalis.

Regular Vs. Feminized Seeds

Your seeds will either be regular or feminized. Regular seeds include both males and females while feminized seeds only have females. Feminized seeds can save you the time and effort in identifying the sex of the seeds during growth. You never want to grow male and female cannabis seeds together unless your goal is producing more plants. The males will pollinate the females, causing the females’ energy to focus on reproduction instead of producing buds. The resulting buds are less potent and desirable.

Do You Want Autoflowering Seeds?

You should also consider whether you want autoflowering cannabis seeds. These will automatically move to the flowering stage of growth from the vegetative stage as they age. This is opposed to the change occurring based on the amount of light received. Some autoflowering seeds will also grow more quickly.

Choose Between Indoor and Outdoor Growing

Most people who choose to grow cannabis will do so indoors. The only issue with indoor growing is that it can be highly inefficient, causing an increase in energy bills. However, outdoor growing also has issues, including fluctuating weather conditions and potential legal restrictions. In most states, you cannot legally grow cannabis outside, eliminating the choice for you.

Regardless of where you plan to grow your cannabis plants, you will need to germinate the seeds indoors. You can still decide at this stage if you will grow the plants inside. This gives you time to prepare the growing area so you can plant your germinated seeds immediately.

In addition to legal restrictions that may require you to grow your cannabis indoors, most people choose this method thanks to the ability to control the growing conditions. By controlling light, humidity, and temperature, you can grow cannabis inside all year round.

Germinate With a Wet Paper Towel

The most popular method of germinating cannabis seeds is to use wet paper towels. You will need your seeds, distilled water, clean plates, paper towels, tweezers to handle the seeds, good potting soil, compact fluorescent lights, a grow light timer, a seed tray, and a pH test kit. Always handle the seeds with the tweezers instead of your hands, as this will improve their chances of flourishing.

Soak the Seeds

Start the process by soaking your seeds in distilled water. Before doing so, use pH test strips to confirm the water’s pH is somewhere from 5.8 to 6.5.

The seeds should float when you first place them in the water, but they will start to sink eventually. You can encourage this by tapping the seeds using your tweezers. Many growers consider this step of soaking the seeds optional.

Lay Out the Seeds

After soaking the seeds, lay two layers of paper towels on a dinner plate. Moisten the towels using room temperature distilled water, but drain off the excess moisture. Spread the seeds out in the center of your paper towels. Make sure there is some distance between each, giving them room to start germinating. Once you spread the seeds out, cover them with two paper towels (also moistened with distilled water) then place another dinner plate over it. The second plate will ensure your seeds stay warm.

Storing and Checking

Put the plates with the paper towels and seeds somewhere that is dark and warm. The seeds’ ideal temperature of germination is between 70 and 90 degrees Fahrenheit.

Make sure to check the seeds regularly throughout the entire germination process. You will likely need to remoisten the paper towels a few times. Whenever you remoisten the towels, make sure you drain the excess water afterward.

Planting the Germinated Seeds

Once germination is done, you are ready to plant the seeds. Fill your seed tray or plastic cups using quality potting soil. Saturate the soil with water. Create one-fourth inch holes in each slot of the seed tray. Place each seed inside, ensuring the taproot faces down. Cover the seeds using loose soil, never tapping it down. Keep the soil moist with a spray bottle.

Within about four to six days, you will likely see sprouts. By 10 to 14 days, the seedlings will likely have leaves. You should put the seed tray underneath fluorescent grow lights. Remember that seedlings and germinated seeds will need 24 hours of light. After you spot the leaves, you can reduce this to 16 hours.

Germinate With Rockwool Cubes

Another popular option for germinating cannabis seeds is to use Rockwool cubes. The cubes do better at water retention compared to paper towels. They also make transplantation after planting easier, and the cubes keep the pH consistent. This method of germinating the seeds requires similar tools, including a pH test kit, tweezers, good potting soil, your grow light timer, compact fluorescent lights, and a seed tray. You will also need the cannabis seeds, one-inch Rockwool cubes, pH balancing chemicals, plastic or metal tweezers, a waterproof tray, and a small pointed object, like a clean nail or toothpick.

Prepare the Rockwool Cubes

Before you start germinating your seeds with this method, stabilize and hydrate your Rockwool cubes. This is necessary since cannabis seeds prefer a pH between 5.5 and 6.5, but Rockwool cubes naturally have a pH of 7.8.

To prepare the Rockwool cubes, start by testing the water you plan to use. If the pH is not ideal, you can decrease its pH value, acidifying it, by adding small quantities of lime juice. Add a few drops, then measure again. Take this process slow since a pH of under five will need you to raise the pH or for you to start over.

Once the pH reaches the proper level, soak your Rockwool cubes in the water for an hour. Take the Rockwool cubes out of the water, without draining them at all. Store the leftover water in a spray bottle or something similar. It has the perfect pH level for watering your cannabis seeds.

Set Up the Rockwool Cubes

Once the Rockwool cubes are soaked, you can go ahead and prepare them for your seeds. Place the soaked cubes in your waterproof tray. If your cubes do not come with preformed holes, poke some using a clean, pointy object. The holes should be about one-fourth inch and wide enough for a seed to fill it.

Set Up the Seeds

Now, you can place a cannabis seed in every hole. Remember to complete this process with the tweezers, so you do not touch the seeds. Use the tweezers, or a toothpick, to push the seeds gently down to the bottom of the hole. Finally, cover each hole with another tiny piece of Rockwool. This will create the moist, dark environment the seeds need to germinate.

Cover your tray using saran wrap or a clear plastic dome. This will further help with the humid environment, as it retains heat and traps moisture. Put the covered tray under a 40-watt fluorescent tube, with two to three inches between the light and plants. Leave the light on 24/7. The seeds will not need the light until the sprouts poke through the cube, but since you cannot monitor them 24/7, it is best to have the light ready ahead of time.

Maintaining and Germinating the Seeds

Keep a thermometer by the tray’s neck, under your saran wrap or dome. This will let you check if the temperature stays between 70 and 90 degrees Fahrenheit. Check on the Rockwool cubes two or three times every day. Use your pH-balanced water to remoisten the cubes if necessary. Remember to keep the cubes damp, not drenched.

Transplanting the Germinated Seeds

The roots of the germinated seeds should start poking out of your Rockwool cubes after two to three weeks. This is the ideal time to transplant the seeds, as you do not want the roots to start tangling. Grab a slab of Rockwool and cut holes that are one-inch deep and 1 1/4-inch wide. Carefully place your Rockwool cubes with the seedlings into each of those holes. Use tongs with extreme caution, so you do not damage or touch the roots of the cannabis seeds.

When placing the cubes in the Rockwool slab, ensure that the cubes are not lower than the surface around it. If it cannot fit at the same height, have it stick out slightly. If you place the cube too low, water can pool, leading to stem rot.

Germinate Directly in Soil

Another option is to germinate the cannabis seeds right into your soil. This will reduce the chances of damaging the seedling during transplantation. To make this easy, get a seed propagation kit and follow its instructions. You can also create your own with the seeds, a waterproof tray, small peat cups, a 40-watt fluorescent grow light, pH test strips, pH-balanced water, a thermometer, and saran wrap.

Get the Right Soil

For this process, start by choosing the right soil. The pH should be 5.5-7. It should also drain well. You may want to add a mycorrhizae mixture to the soil, as it provides fungi that help with the growth of plant roots.

Prepare the Soil and Seeds

Use the soil mix to fill your peat cups. Then make a hole in the center of each cup about one-fourth inch deep using your finger. Place one seed in the hole before loosely covering it with soil. Put the cups in your waterproof tray and moisten the soil without drenching it using the pH-balanced water. Make a dome on the tray with saran wrap, supporting it with toothpicks.

Place your tray and cups with seeds and soil three inches under your light. Leave the light on for 24 hours until you notice sprouting.

Monitoring the Seeds

Check the set-up two or three times each day to ensure it stays moist, spraying it with the pH-balanced water if necessary. Make sure also to monitor the temperature of the area. Once the seeds sprout, you can continue growing them like you normally would, transplanting them to larger pots when necessary.


No matter which method you choose for germinating your cannabis seeds, make sure to provide the seeds with the proper pH level and the proper temperatures, humidity, and moisture. You should notice the seeds germinating within just a few days or a week, getting you ready for your next step in growing cannabis.

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