When cannabis seedlings have grown their second or third set of serrated leaves they are usually hardy enough to flourish in direct sunlight. Learn when that is and how to do that now. If done incorrectly, germinating cannabis seeds can be a struggle. Luckily, we're here to help! Check out 5 germination mistakes you need to avoid! One of the most tricky things about growing your own cannabis is how to correctly germinate cannabis seeds. Here's an easy guide on how to go about that.
When can seedlings be put under lights or in the sun?
Not sure whether to grow your cannabis seeds in the sun or under lights? This article explains how much light you need, how to prevent your seedlings from falling over, and when to plant them outside.
“When can cannabis seedlings be put under lights or in the sun?” is a common and sensible question that is often asked by novice cannabis enthusiasts after germinating seeds indoors under lights.
For those who are growing indoors, cannabis seedlings may be put under lights as soon as they emerge from the soil or growing medium.
How much light for cannabis seedlings?
When using HID lighting (usually a metal halide lamp), young seedlings should be kept at least 50cm from the bulb.
With compact fluorescent lamps (usually 100w or more), a distance of around 15cm should be maintained between the top of the young seedlings and the bulb.
If using normal fluorescent tubes (18-36w), seedlings can be kept within a few centimetres of the light source.
Cannabis seedlings growing under lights should always be given a gentle breeze from an oscillating fan (a small household fan on the lowest setting is fine), as constant gentle movement will strengthen their stems significantly.
Are your cannabis seedlings falling over?
If cannabis seedlings grow tall and then fall over, this is almost always a result of growing in an environment with static air.
Seedlings intended for outdoor growing should be kept by a sunny window for the first week or two after emerging from the soil.
When they have grown their second or third set of serrated leaves (after the the round cotyledons that initially emerge from the seed) seedlings are usually hardy enough to flourish in direct sunlight.
When to plant your cannabis seedlings outside?
If outdoor temperatures are suitable, seedlings may be acclimatised to direct sunlight by giving them progressively longer daily exposure to outdoor conditions.
Starting with about three hours outside, at the sunniest time of day, seedlings can be given an extra hour of outside exposure each day, so that within about two weeks they can be left outdoors permanently.
Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.
Top 5 Germination Mistakes To Avoid When Growing Weed
Germinating cannabis seeds is necessary in order to sprout seedlings that develop into mature, healthy cannabis plants. However, complications with light, humidity, heat, and more could result in cannabis seeds failing to sprout. Find out what to avoid to ensure successful germination.
Germination is where the magic begins. Cannabis seeds must first germinate in order to sprout and begin their journey as living, breathing plants. However, if the germination process is done incorrectly, or is thwarted by some other variable, seeds can fail to sprout, leaving you with useless, spent seeds instead. Here are the top five mistakes to avoid when germinating cannabis seeds.
GERMINATING BAD SEEDS
One of the most common reasons seeds fail to germinate is because they are simply duds. Typically, healthy cannabis seeds should look a specific way and be of a specific colour. Viable seeds will appear round, not flat, and should be a beige to dark brown colour with subtle tiger striping. Seeds that have been flattened or are pale in colour may have a tough time sprouting into healthy cannabis plants.
Seeds that have been improperly stored may also fail to germinate. These tiny packages of DNA prefer to be kept in a cool, dark place with moderate humidity. Exposing them to heat, light, or extreme humidity levels (both high and low) could result in seeds losing their viability. As long as you source your seeds from reputable seedbanks and store them appropriately, you shouldn’t have to worry about bad seeds ruining your chances of successful germination.
TOO MUCH LIGHT
Generally speaking, seeds require a dark environment in order to germinate. After all, in nature cannabis seeds find their home in the dark embrace of soil. It can be hard to determine exactly how much light is too much for your seeds; however, err on the side of caution and germinate out of direct light. There’s no need to use your grow lights until after germination has occurred.
It is also likely that the quality of your seeds will affect their ability to handle direct light. Seeds that are already having a tough time germinating will have an even worse time doing so if they are exposed to excess light.
TOO MUCH OR NOT ENOUGH WATER
The amount of water you supply your seeds during the germination process will also affect their ability to successfully germinate. Some growers attempt to germinate by “drowning” them in a glass of water. While this ensures they will not go thirsty, it can actually be more harmful than helpful.
Once they pop, seedlings are very delicate and must be watered carefully. When germinating, your medium should be damp, but not overly wet for best results. On the other hand, a dry environment is basically a death sentence for your seeds. They need a constant source of moisture to sprout, otherwise they’re good as duds.
Cannabis seeds require a specific temperature range in order to germinate. Regardless of the germination medium you are using (soil, paper towels, etc.), the temperature in the environment should consistently sit in the 26–28℃ range. Seeds need to be kept warm during the germination process. At no point during germination should seeds be exposed to temperatures below 20℃.
There are some techniques that can be used to ensure your seedlings remain in this temperature range. Some growers choose to use special warming mats that can be set to a specific temperature and placed underneath the seedling containers. Another strategy is to place a timed heater close to your seedlings to warm them up occasionally. Once your seeds have sprouted, they will be much more resilient to fluctuations in temperature.
GERMINATING IN SOIL
Many people choose to germinate their seeds using paper towels. However, others choose to do so directly in soil. Of course, germinating your seeds in soil isn’t inherently bad, but it can come with its own set of challenges, and is generally not recommended unless necessary.
For instance, the upper layer of soil can dry out within 48 hours, making it more difficult to give your seeds the right amount of water they need without overdoing it. Giving your soil too much water during germination could result in the seed rising up or dropping down further, inhibiting its viability. Moreover, seeds that are planted too deep in the soil could experience a host of complications. They could suffocate before coming into contact with enough oxygen, and be unable to access sufficient light to progress into the seedling stage of their life cycle.
Seeds may also be unable to germinate if the soil they are planted in contains contaminants. Mould and pests can easily kill a mature, healthy weed plant within just a matter of weeks. It should come as no surprise then that they could also prevent a small seed from germinating. If your soil contains traces of these contaminants, it is possible that your seed will never actually open and sprout. This also applies to fertilisers. Even small amounts of fertiliser in your soil can effectively kill your seed, making it completely useless.
How To Germinate Cannabis Seeds
Growing your own weed is fairly easy, as explained in our article ‘All You Need For Growing Weed At Home‘. The hardest part for some growers though, is germinating their newly bought cannabis seeds. After all, the vulnerable seedlings are easily damaged. However, making sure your cannabis seeds survive germination is essential for a successful grow. In this blog, we highlight three tested methods that let anyone germinate cannabis seeds with minimal effort.
How To Germinate Cannabis Seeds, Step 1: Get Good Genetics
We cannot stress this enough. If you want good results, you are going to need good materials to start with. In case of growing cannabis, the first thing on that list are good cannabis seeds, of course. Besides high quality cannabis seeds all you need is some water, a warm environment (between 20-25 degrees Celsius) and – lack of – light to start germinating your future cannabis plants.
Even though living weed plants love (and need) a lot of light, germinating cannabis seeds thrive better in a dark environment. And just like there are different methods of growing your own cannabis, there’s also a choice in how to make your seeds sprout.
Want good cannabis? Get good seeds!
Germination is actually a process where you activate a dry seed that is in a ‘sleeping state’. By adding water to the seed, a small root that is inside the seed-shell will want to come out in search for more water. This will make it develop into a big taproot that’ll serve as an anchor for the plant and from which more roots will sprout. Read more about root-development in this article: ‘Clones vs. Seeds: What Grows The Best Cannabis?‘
Germinate Cannabis Seeds In Water
The easiest way to germinate your cannabis seeds is to let them soak in a glass of water. The seed will absorb the water and due this process hormones will make the seed start to grow: expansion and elongation of seed embryo.
You will see them sprout after 24 to max. 48 hours. Note that you need to store the glass of water in a dark place on roomtemperature. After sprouting they are ready to plant in soil, 1cm to max 2cm deep. All they now need is love, light, water and heat!
Ready to sprout!
How To Germinate Cannabis Seeds: Wet (Paper) Towel Germination
The best known way of germinating cannabis seeds is to put them on or between wet paper towels or cotton wool. This method exists in different varieties, as it’s not so much about the paper itself, but more about the absorbency of the material. It’s very easy to make sure the ‘medium’ doesn’t get too soggy and doesn’t dry out easily. If it does dry, you can effortlessly add a few drops of water to immediately re-moisten it.
Wet paper towels are probably the most common way of germinating cannabis seeds
The goal here is to balance out the moisture so it’s not too dry, nor to wet. Go for a piece of paper that is moist all over, but doesn’t drip when you pick it up. If the seeds stay to dry, the root that’s supposed to sprout won’t be able to make it out of its shell in search for water. If the paper is too wet though, the root will come out and quickly stop looking for water; as it’s already soaked in it. This stops the development of the root, delays the growth and might even cause the seeds to rot after a while. So, be careful not to give too much water as this is one of the most common rookie mistakes when it comes to growing weed!
Transplanting In Soil
After the root has sprouted and has gained a few millimetres in length, it’s time to transplant the seedling into its soil and put it under a light-source. As a rule, a small 1cm deep hole made with your fingertip should do. Gently pick up the seeds one by one, taking care not to touch the root. Use a clean pair of tweezers and don’t squeeze. Make sure that the roots don’t cling to the paper or cotton wool. Lovingly cover the seed with a little (loose) soil and add a few drops of water. Now, all you can do is wait whole the story continues below the surface. As soon as the seedling pops her head above the ground and green leaves emerge, she’ll needf light to continue growing.
This is the part where most growers (especially the hasty ones) sometimes lose a seed. Remember that you are handling a baby plant here. The vulnerable root is easily damaged during the transplant. If you don’t trust your steady hands, it might be better to choose another germinating method.
How To Germinate Cannabis Seeds In Soil
Another common method of germinating cannabis seeds, and probably the most natural one, is to stick the seeds directly in their intended medium: the soil. You can do this with or without soaking it in root stimulator for a few hours first.
By planting cannabis seeds directly in their soil or coco – or whatever other medium you might be using – growers cause the minimal amount of stress for the plant. Direct planting also allows the taproot to immediately dive as deep into the ground as possible. Furthermore, its leaves can enjoy the light as soon as they emerge from the developing seed. This way the seedling can start its growth with a fair chance, providing you with a steady, high-yielding cannabis plant.
Cannabis seeds and sprouted seedlings require constant temperatures of around 20-25 degrees Celsius
For this method, simply prepare your medium by moisturizing it, again, without soaking the soil completely. Then take your flower pots and use your finger to make a small hole about 10-15mm deep in the top layer to put the seed in. Cover the seed up loosely and top it off with a little water. Be careful not to give too much at once though! A stream of water can cause the seed to travel further down the pot where it’s too moist – and too deep to travel back up again.
The top layer is the perfect place to germinate cannabis seeds, as it dries out faster than the soil further down the pot. This makes it easier to ensure the right level of moisture for the seed to germinate. If it gets too wet, the seeds will rot in the soil. If it stays too dry, the plant will not be triggered to emerge from its shell. Again, it’s all about finding the perfect balance between too wet and too dry.
How To Germinate Cannabis Seeds in Plugs
Last but not least on this list is the germination of cannabis seeds in special plugs. These plugs are available in various materials, especially designed for quick and efficient germination of cannabis seeds.
Plugs are a practical way to germinate cannabis seeds
Most plugs are dry blocks of (usually) coco fibre. Peat plugs are an interesting alternative, as these contain some initial nutrients to help the seedling along. After fully absorbing about 500ml of moisture, or 250ml of a root booster and another 250ml water, they slowly turn into a moist, soil-like plug. Grow plugs usually have a premade hole in which to place the seed. After sticking the seed in the top of the plug, cover it lightly with a little leftover plug fibre. It takes a few days at maximum before you see the first heads pop. As soon as the roots grow out of the bottom or the side of the plug, you can stick the entire plug, complete with its seedling, into your intended medium. These plugs make germination and the initial transplant a piece of cake.
A fantastic view on this seedling with it’s shell sticked to her leaves
After Germination: Growing Your Seedlings
So there you have it: whichever method you chose, germination should now be underway. Remember that even the best seed banks work with organic, natural materials, so 100% germination rates can never be guaranteed. If you get your technique right, though, most or all of your seeds should germinate according to plan. Once your seeds have become seedlings, the next steps of your grow await. There’s a lot of choices to make from here to harvest time: indoor or outdoor, which spot to pick, what nutrients to use, and so on. Keep an eye on our expanding grow blog collection if you want to learn more!