How to Germinate Cannabis Seeds
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The Germination Process
Cannabis seeds can be stored in a dormant state for more than a decade if you can keep them cool, dry and in the dark. When you are ready to grow your seeds you must choose an appropriate method to introduce the correct conditions and begin germination.
The introduction of warmth, light and moisture will signal to the seed to begin to break down its stored nutrients and use them to grow into a seedling. The first thing to grow from a cannabis seed is the main root known as the tap root. When you see this small white root begin to appear you will know that germination has begun.
Ideal Germination Conditions
Germination is the physical and chemical change that occurs to a seed when the right environmental conditions are provided.
These conditions are:
- A moist environment.
- A temperature between 20 and 28⁰C.
- Direct light or sunlight.
What’s The Best Method?
When you begin to germinate cannabis seeds you will be hoping to successfully grow most or all of your seeds into plants. For a large number of your seeds to grow into plants you will need to be aware of the main threats that will face a germinating cannabis seed:
- Incorrect germination conditions.
- Damage to the seed or new structures as they grow. This can occur from touching or moving the germinating seed. Or it could have been damaged before it arrived if you didn’t buy from a trusted seed bank.
The most successful method is one that will help you easily overcome these obstacles with minimal effort.
The Compost Plug Method
Compost plugs can be found in most garden centres or bought online. They are pods of dried compost which can be used to plant seeds in once they have been soaked in water. You can also buy similar plugs specifically for cannabis seeds which may contain additional nutrients.
- Purchase compost plugs or cannabis seed starter cubes. The plugs and cubes will come with their own preparation instructions to follow. Soak the compost for the time indicated by the instructions. You will see when the compost is ready because it will swell up. Keep soaking it until there are no visible dry patches and it feels spongy when you squeeze it.
- Squeeze each plug to drain the excess water. Moisture is crucial for germination but it is important that the plugs don’t become water logged. Water logged seeds risk the development of rot or fungal growth.
- Place your plugs into a seed tray or small flower pot. These must have small holes for drainage.
- Poke a small hole into the top of the plug and place one cannabis seed per plug about 1.5cm deep. Ideally place the seed with the slightly pointed end facing down but this will not be a big problem if you forget or place it incorrectly.
- Gently cover the seed with loose compost from the plug.
- Place your seed tray or pots in a warm room or in a specialist heating device. The temperature you are aiming for is between 20 and 28⁰C.
- Keep your compost plugs moist throughout germination.
- As soon as you see the seedling begin to appear place them under a direct light source. This could be artificial light or sunlight. A fluorescent light works best because they use less energy and don’t produce too much heat. Place the lamp as close to the seedlings as you can.
- Your seedlings should appear and grow over the next 3 to 8 days.
What Other Methods Do People Use?
The Paper Towel Method
This is a low cost method that can be very successful. However, it does come with increased risk because it can result in accidental damage to the young plant structures. The cannabis seeds are left on damp paper towel and are ready for transplanting into soil or other growing medium in 1 to 3 days. If the seeds are a little older this can take longer. The germinated seedlings have to be handled to do this which can result in serious damage. It is very easy to not be gentle enough and also you can transfer other diseases.
One to be careful of if you are a smoker is Tobacco Mosaic Virus (TMV). A good precaution to take when handling seedlings and the seed itself is to wear gloves.
Germination For Hydroponic Systems
Those who grow cannabis seeds in hydroponic systems often start with the paper towel method and then transfer the young seedlings into a rapid rooter. This is a plug similar to a compost plug but is fortified with nutrients to optimise healthy plant growth. It is also possible to germinate seeds directly in a rapid rooter to cut out any extra handling during transplantation.
Buy Rapid Rooter trays from Growers House.
Some growers plant their seeds directly into soil. This minimises handling of the seeds when they are most vulnerable. The soil should be kept moist and the environment should be between 20 and 28⁰C as with other methods.
Those who have a little more money to spend on germinating their cannabis seeds sometimes invest in a germination station. This is a self-contained unit in which compost plugs or rapid rooters can be placed to be kept at the correct temperature and moisture level.
Buy a germination station for $30 here.
Glass of Water Method
This is the simplest method and involves placing cannabis seeds in warm water. They are then left for 1 or 2 days until the small taproot appears. If they haven’t germinated in 36 hours they are moved to a paper towel or something similar to complete the process. While this method still has the dangers associated with handling the young plants it is an excellent way of reviving old seeds that have dried and developed a harder shell.
Transplanting Your Seedlings
Transplantation is the process of transferring your seeds from their germination medium into soil or other growing medium. You may need to do this again later on but the initial transplantation is the most risky because the cannabis seedling is still very delicate and easily damaged.
Our preferred method of germination with compost plugs makes transplantation incredibly easy and reduces the risk of damage to your plants:
- Prepare a plant pot with soil or compost and make a small hole in the centre of the soil. The hole should be slightly larger than your compost plug.
- Remove the plug from the first tray or pot without touching the seedling. Place it inside the hole in the larger pot and gently ease some soil around the seedling.
- Now continue to keep it moist and care for your seedling as it grows into a plant.
How to Germinate Cannabis Seeds:
- Soak your compost plug until moist and spongy.
- Place your plug into a seed tray or small pot.
- Make a hole in the top of the plug 1.5cm deep.
- Place your cannabis seed in the hole with the pointed end downwards.
- Gently cover over the seed with compost.
- Maintain a temperature between 20 and 28⁰C.
- Keep the compost plugs moist.
- Introduce a direct light source as soon as the seedling begins to appear.