The seedling stage of cannabis growth is easily the most vulnerable your plants will ever be. For this reason, it is more important than ever to know how to look after them properly. If you get it right, you will ensure your budding little beauties will have the best start in life possible, creating a solid foundation for the rest of their lifecycle to grow off of.
IT’S ALL ABOUT ENVIRONMENT
In order for a seedling to thrive, it needs a consistent and stable environment. This includes a consistent temperature, humidity and airflow. There is no more efficient or easier way to do this than by using a seed propagator. This inexpensive piece of kit is basically a mini greenhouse, and ensures that your seedlings remain within their own contained environment.
There are a few ways of obtaining a propagator. Firstly, you can create your own. This can be as simple as securing a clear plastic bag over the top of your pot, with a few air holes for ventilation. Alternatively, you can buy a proper propagator. This will usually cost you in the region of €10-40 depending on its features, and will offer a great deal of control over the environment for your seedling. Such features can include thermometers, inbuilt heating, lighting, and controlled airflow. It really all depends on how much you want to spend, and how much control you want over the seedlings.
You can check out the propagator we have in our store as an example, but your local gardening centre is also likely to stock something along the same lines as well.
To begin with, you will want to maintain a consistent root area temperature ranging between 19-24 degrees. This will help ensure that all your seedlings develop at the same speed. An easy way to achieve this achieve this is with a seedling heating mat, which can sometimes be included with a propagator, or bought separately.
Once all of your seedling are fully showing out of the soil you can start ‘hardening the off’. This basically means you start gradually acclimatising them to the environment outside of the propagator without causing them to go into shock. This is done by increasing the amount of air holes in a plastic bag each day, or gradually opening the air vents in a propagator to increase airflow.
GETTING THE LIGHT RIGHT
The next very important thing to consider is lighting. Although HPS lights are great when your cannabis grow is in full swing, they can often be a bit much for seedlings. A great way to start them is with a CFL light. CFL lights do not put out too much heat (unlike HPS lights), meaning they can be put very close to your seedlings without causing any damage, yet at the same time offer a great light coverage. This ability to place your lights in close proximity also stops your seedlings from stretching, as they do not need to try and grow too tall too quickly to reach the light.
In terms of colour bands, seedlings do best under a blue spectrum, so try and find a bulb that focuses on this – cool white and soft white bulbs tend to be the ones, but double check the specifics of the bulb before you buy anything.
Lastly comes lighting schedule. You can subject your seedlings to an 18/6 schedule without any worries. This will cause the healthiest amount of growth.
FEEDING YOUR CANNABIS SEEDLINGS
The last essential piece in seedling care is feeding. You should not need to give your seedlings any additional nutrients. At this stage, they should be able to get everything they need from the soil, and since they are so delicate in this stage of their life, giving them anything extra is likely to cause nutrient burn, and death – so don’t do it!
All you need to think about is watering you cannabis. At this stage, you only need to use plain water. It should ideally be in a pH range of 6.3-6.5, and if you are using tap water, make sure it has been set aside for at least 48 hours before giving it to your cannabis. This allows the chlorine and other chemicals in tap water to evaporate first.
Water your seedlings whenever the soil begins to feel dry to the touch. You do not want it to be constantly moist, as roots grow most efficiently though depletion – meaning that once they have absorbed all of the water in one area, they grow and seek out other areas that may contain water. If roots have a constant supply of water, not only does it increase the chance of root rot, but also removes their drive to grow.
Note: If you are growing in a more advanced medium, such as rock wool, than your seedlings will not have access to the natural nutrients found within soil. You will need to offer nutrients with your water, usually at ¼ the usual strength.
There you have it! It is easy to look after seedlings when you know how. What they need is stability and consistency, as long as you can offer them that, you will be laughing all the way until they are ready to transplant (usually at 10 days after germination).