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best temperature to germinate cannabis seeds

When the seedling stems reach two to four inches in height, it’s time to transplant your cannabis into larger pots with more room for roots to spread down and out. After you’ve done this, you’ve successfully germinated your cannabis seeds into proper, young plants.

Soil is an easy, more natural method with which to germinate your cannabis seeds. The soil protects the fragile roots from any interference, and soil is, after all, where a cannabis plant would grow in the wild.

First, make sure you use the correct type of soil, either gently fertilized potting soil or a seed starter with a pH level of approximately six (6). The soil contains the right acidity and enough nutrients to strengthen your young cannabis plants for the first two weeks. Be careful not to add more nutrients, or you risk overfeeding and killing your seeds.

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Germination itself is a crucial aspect of cannabis cultivation. The seed germination process is the foundation of every marijuana plant, and steps can be taken to boost successful popping. For example, some cultivators improve germination attempts by soaking seeds in 1% hydrogen peroxide or a compost tea for 12 hours beforehand to kill any dangerous pests.

While many plants can be germinated in the ground, cannabis seeds are fragile enough that you should germinate them before planting.

Use a spray bottle to moisten the paper towels and then store the cushioned seeds between two plates, under a face-down bowl, or gently place them in a plastic bag. Photo by: Gina Coleman/Weedmaps

Lay one paper towel on top of a countertop, place a few seeds, and cover them with a second paper towel. Photo by: Gina Coleman/Weedmaps

Sean 2021-05-17
I had my seeds in the paper towel for 3 days. The tap-roots appeared(not out just showing a bit) and I planted them in the soil. 3 days have past and I haven't seen any progress. Is there a reason why this is happening?

Although the germination of cannabis seeds is a relatively quick and easy process, it is crucial to take into account a series of important factors in order to obtain as high a germination rate as possible. In addition, it’s in our interest that the seeds germinate as quickly as possible, and especially if we want to avoid problems like fungal infection or a low germination rate.

If you look closely at a cannabis seed, you will notice that it has a slightly oval shape, ending in a point at one end and forming a small “crater” at the other end, which is called the crown. When planting your seed (whether it’s a seed that you want to germinate, for example, in a jiffy, or a seed already germinated on kitchen paper that you want to transplant) you must keep in mind that this crown should always be facing upwards.

Planting several seeds in the same pot

To avoid these problems it is be best to sow the seed at about 2cm depth. In addition, we can cover the lower stem as the seedling grows, so that it gains stability and produces new roots along the length of stem we have buried. In this way we can accelerate the growth of the plants.

The paper towel should never dry out once germination begins

Tim 2021-05-17
Hi Sean, thanks for your comment. As long as the soil is neither too wet nor too dry, there shouldn’t be a problem with the seeds. They can take a few days to pop their heads up above the surface once they’re planted, the root needs to work its way downwards and find a solid hold to be able to push the seed head out of the soil. Speaking from personal experience, don’t be tempted to dig around looking for them as you’ll probably do more damage than good. The only times that seeds didn’t come up for me were the times I overwatered them, it’s crucial that they get enough air at this moment and too much water can lead to them rotting quickly. Of course, if they totally dry out then they’re not going to survive either. At this stage, I’d just recommend patience, good luck! Best wishes!

Tim 2021-05-13
Hi, thanks for your contribution. Mandala Seeds give some helpful advice but they don’t have a monopoly on germination methods! In my 20 years germinating seeds I’ve tried all different methods and I’ve found good and bad in all of them. except for the methods using moist paper towels, I refuse to use it these days – I found that’s a great way to get mold problems and a really bad start to the plant’s life! That definitely is far too much humidity. as for ambient humidity, we don’t specify anything in this post. What we do say is that the medium in which the seeds are germinating should be at about 70% humidity for the best results. There’s nothing wrong with using a humidity dome or mini greenhouse, as long as you know when to start ventilating. of course if it’s kept sealed all the time then problems are bound to arise! These days I start all mine in a glass of water with a few drops of H202 and then once the seeds open (usually 24 hours) they get transferred to the substrate. As for the point down/point up debate, I think I’ll need to do a side-by-side comparison to settle this in my own mind. I’ve always planted them point downwards or on their side and I’ve yet to see any weird stuff like roots popping out of the surface, or doing a loop-the-loop before the seedling breaks the surface. But it’s clear that the debate needs to be settled so I’ll do an experiment and I’ll be happy to be proved wrong! EDIT: I’ve since germinated over 100 seeds as a test, 1/3 of them went in the soil with the point downwards, 1/3 sideways, and 1/3 with the point upwards. Most of the seedlings broke the surface at around the same time but it’s clear to see that the ones that I’m still waiting for are mostly those that went in with the point upwards. The next step has to be a test in a terrarium so I can actually see what’s going on but I’m almost ready to call complete BS on this “point upwards” theory, FWIW. Thanks again for your comment, all the best!

– 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.

– On the one hand it has the ideal structure, that is, the amount of air and water in the substrate is adequate for germination.

You can germinate your cannabis seeds both indoors and outdoors, though our recommendation is that you do it indoors, as you will have more control over all the factors that can have a negative effect on the process. But if this is not, below we explain the best way to germinate seeds outdoors.

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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.

Now that you know how to take your first steps, you’re ready to start this season’s crop. Have a good harvest!

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 all the elements necessary to nourish your seed/seedling during the first week; the ideal amount of nitrogen, phosphorus, potassium, calcium and magnesium. Phosphorus and calcium are particularly important for the correct development of roots.