The growth stages of marijuana can be broken down into four primary stages from seed to harvest:
The first marijuana plant stage begins with the seed. A cannabis seed should feel hard and dry, and be light- to dark-brown in color. An undeveloped seed is generally squishy and green or white in color and likely won’t germinate.
Notes on marijuana growth phases
Cannabis plants go through a series of stages as they grow and mature, and those different growth stages call for different amounts of light, nutrients, and water.
If you need to determine the sex of your plants (to discard the males), they will start showing sex organs a few weeks into the veg stage. It’s imperative to separate males so they don’t pollinate the females.
Two rounded cotyledon leaves will grow out from the stem as the plant unfolds from the protective casing of the seed. These initial leaves are responsible for taking in sunlight needed for the plant to become healthy and stable.
Placing healthy & fresh seeds in water/wet tissue can lead to the development of fungi or bacteria on the seed hull. Lack of oxygen and contaminating substances in the water/wet tissue promote fungal growth which can be transported to the substrate later on. Often the seed simply rots away if left for too long in a glass of water, or wrapped up in wet tissue.
Take 8-10 cm/3-4” (diameter) pots or a seedling tray and fill with quality potting soil. Press the soil slightly down and make a 1,5 cm/0,6” deep hole with a pencil or finger. Place the seed in a horizontal position in the hole (this is the easiest method). Fill the hole and gently tap down the soil. Use chlorine free water (preferably good mineral water without gas) with a pH of 6-6.5 to water the pots. The soil should be uniformly moist and properly watered, but not soggy or waterlogged. The pots or tray should also not stand in a tray filled with water. Use a spoon or small beaker to dosage properly if you are unsure and want to avoid accidentally overwatering the soil. Put the pots or tray at a warm location and ideally under lighting. Temperatures at 25°C/75°F or higher accelerate germination. Take care that the soil does not dry out and that the pots don’t stand in the cold (ie. at or under 21°C/70°F). Misting the soil surface with water spray is not effective. You should water the pots properly if the soil surface dries up. Within 3-7 days the seedlings should appear out of the soil. You can switch on your lamps during germination to provide warmth or when the first seedlings appear. Since they might also grow out of the soil during the night it's best to have lighting switched on 24 hrs.
Germinating cannabis seeds is not difficult.
We provide the basic information and many hot tips on what is important to support you in having a successful start!
IMPORTANT: Don’t cover pots with plastic wrap, don’t use a humidity dome to seal off the pots, or place pots/rockwool cubes in a propagator that’s completely covered! This prevents fresh air exchange, raises humidity to excess levels, and easily facilitates the spread of fungus. The seeds will rot before they can germinate. Excess humidity combines with lack of oxygen is the #1 cause for poor germination results!
Professional horticulturists rarely use pre-germination methods to actually grow out the seedlings because of the shock suffered from transplanting them. For example, we use the paper tissue method only as a quick test for germination rates of aged seed stock from our genetic repository. This allows us to see beforehand how many seeds we have to put in soil to get the amount of plants we require for breeding projects.
Cannabis is not an orchid or swamp plant! The seeds need a well aerated growing medium to germinate well. Seedlings also cannot tolerate high humidity and can easily be attacked by fungus such as fusarium and pythium. Only the soil or growing medium should be moist for optimal germination and seedling growth. Ambient humidity is best at or below 50%.
However, there are people who germinate marijuana seeds in paper towels. Why don’t we recommend them? Well, although this method may be effective, it is not the most adequate and has some disadvantages. To start with, the seedlings do not receive the necessary light, as the paper towel that covers the top prevents the sun’s rays from penetrating. In turn, in the Jiffy they do receive light, and therefore photosynthesis will start earlier. Another advantage is that as soon as the root emerges in the Jiffy, it starts to turn downwards and to absorb nutrients: on the one hand we accelerate the process and on the other, when we replant the Jiffy 7 with the seedling there is no transplant shock.
– It has a neutral pH, which is the most adequate and makes it the perfect medium for germination; during one week you just have to add water.
Our first recommendation, as we already said, would be to wait for the good weather to settle in. Having a high temperature (from 22 to 26°C) is an important factor for your seeds to decide to emerge into the world.
Differences between cannabis and hemp
– Another advantage is the specific temperature: water has a low specific temperature. This means that if we place a glassful of water in a room at 25°, it will be very hard for the water to reach that temperature. Therefore, if we place the cannabis seeds in a very watery medium (a glass or between paper towels) the temperature will be lower, while in a Jiffy, as it is more exposed to the air, the temperature will be higher and the process, faster.
Ventilation is an important factor; don’t make the greenhouse airtight, open the trapdoors to allow adequate ventilation and as the covers are made of thin plastic, you can even make some extra holes if necessary.
Outdoors we never know what dear mother nature has in store for us; in the same way that your seeds might enjoy a week of good weather and sun, there can also be thunderstorms and low temperatures on the very day they sprout. Not to mention the large variety of birds, snails and other fauna that delight in eating those tender and tasty marijuana seedlings. Bear in mind that during their first moments of life, your plants are defenceless against many dangers that threaten them; therefore, it is your job to take care of your little ones and keep them safe. How? It’s actually quite simple, you can buy mini-greenhouses for germinating or you can use a Tupperware and make holes in it for adequate ventilation, although we recommend the first option.
For indoors: The same but under a grow light, fluorescent or LED. If you have the option of germinating your cannabis seeds inside your home, ideally the light intensity will be high; the less intense the light, the more the seedlings will stretch in search of light and become spindly. If you use a 400 W light ideally it should be 40-45 cm away.