What is the germination time of cannabis seeds?

The germination time of cannabis seeds is the process that transforms a seed into a plant and marks the first step in any cultivation. Some vegetable seeds can simply be tossed into moist soil and will germinate spontaneously. However, with certain plant species, such as cannabis, it is best to germinate seeds in a controlled manner to ensure a higher success rate. 

How to determine if a seed will germinate

How to germinate cannabis seeds? There are different methods to do so, such as using germination kits, jiffy pellets (compressed peat disks), paper towels, water, or pots. Each of these techniques has its advantages and disadvantages. Even with expertise and the best equipment, some seeds simply won’t sprout. After all, nature and living organisms are unpredictable and follow their own rules. 

Before germinating or planting the seeds, they should be carefully inspected. If done correctly, most seeds will germinate, but occasionally, low-quality seeds will result in weak plants. A helpful tip is that darker-colored seeds are stronger and have a higher chance of germinating, while seeds that are light green, pale, or white are more likely to fail. Even if a seed has minor damage to its outer shell, it is worth attempting to germinate the darker ones as they are more likely to succeed. 

Optimal conditions for germination

The environmental conditions for cannabis seed germination differ from those required by seedlings or mature plants.

• The ideal temperature should be between 22°C and 25°C (72°F and 77°F).
• The growing medium must remain moist but not soaked.
• The relative humidity should be between 70% and 90%.
• Seeds prefer fluorescent lighting (cool white, code 33-640), although they can also germinate in darkness.
• Handle seeds as little as possible.
• For hydroponic or rock wool setups, the ideal pH level is between 5.8 and 6.2.

Stages of seed germination

Seed germination is a fascinating transformation process that unfolds in several stages.

Imbibition

This occurs when the seed begins to absorb water, swelling to break its shell and open up. As water content increases, enzymes activate, breaking down stored materials like starches or lipids, thus initiating the germination process.

Radicle activation

The radicle is the first root to emerge from the seed, growing downward to access water and nutrients. 

Stem emergence

The stem grows in the opposite direction of the root, reaching toward light to develop the first leaves. 

Leaf growth

The leaves that sprout from the stem begin expanding under sunlight to perform photosynthesis, generating the energy needed for continuous growth.

Germination time of cannabis seeds

The germination time of cannabis cannabis seeds varies significantly. The estimated range is between 2 to 7 days. This variation depends on several factors, including seed genetics (for instance, autoflowering cannabis develops much faster), environmental conditions, light type, substrate quality, and care provided. 

Methods for germinating marijuana seeds

To germinate cannabis seeds you need to create the right conditions for the seed to absorb water and imbibition to start developing the taproot. These are the most commonly used techniques.

Wet paper

This is one of the most popular methods due to its simplicity and effectiveness.

• Place a napkin or absorbent paper on a plate.
• Moisten it with water (preferably distilled or with a pH adjusted between 5.5 and 6.5).
• Place the seeds on the paper and cover them with another damp napkin.
• Cover the plate with another plate to maintain moisture and darken the environment.
• Place everything in a warm spot (20-25 °C) and check every 12-24 hours to maintain moisture. In a few days, the root will emerge and can be transferred to the substrate.

Direct germination in substrate

This simulates the natural process by placing the seeds directly in soil or a growing medium but in a more controlled manner.

• Fill a pot with a light, airy, and moist substrate.
• Make a small hole 1-2 cm deep.
• Place the seed with the tip facing down and cover it lightly with substrate.
• Spray water to keep the medium moist (without over-wetting).
• Place the pot in a warm spot with indirect light.

Water glass method

This method is ideal for harder or older seeds.

• Fill a glass with lukewarm water (20-25 °C).
• Submerge the seeds and leave them soaking for 12-24 hours.
• Once the seed sinks or slightly opens, transfer it to the damp paper or substrate.

Important: Do not leave the seeds in water for more than 24 hours to avoid suffocation or rotting.

Germination in Jiffy (Peat Pellets)

Ideal for simple and safe transplants.

• Hydrate the peat pellet with warm water until it expands.
• Make a small hole in the center of the pellet and place the seed.
• Keep the pellets in a warm and humid place with indirect light.
• Ensure the pellets do not dry out during the process.

Using electric propagators or germinators

Seed germinators are devices that control temperature, humidity, and light for successful germination.

• Place the seeds in the substrate included in the propagator.
• Adjust the temperature (20-25 °C) and humidity (70-80%).
• Monitor daily to identify the moment of germination.

In summary, the germination time of cannabis seeds is quite variable depending on different factors. When should you consider it a loss? Approximately, you can expect about 2 to 3 times the average germination time. For example, if it should germinate in 2-7 days, wait about 15-20 days before discarding it.