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do you need light to germinate weed seeds

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.

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.

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.

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℃.

HPS Or MH For Seedlings
You can put seedlings under HPS or MH light, but I would only suggest this if you already have the lights. It is more cost effective to use LED or fluorescent lights.

My Seeds Germinated, Now What?
Once the seeds have germinated, it is time to transplant them into soil or a growing medium. Be very careful not to damage the delicate taproot. Ideally, use tweezers to handle the seeds, to avoid any oils from your fingers doing any damage.

All you do for this method is poke a hole in the soil or growing medium that is about half an inch deep (1.5 cm). Place the seed in the hole and cover it up. Ensure that the soil or growing medium is moist, but not soaking wet. The temperature needs to be in the correct range as well.

If you do not have a grow light, there are a number of different types you can consider. For seedlings, fluorescent lights or LED light bars (like the veg/clone bars from Secret Jardin) are ideal, unless you are germinating a lot of seeds at once. Then you might want to consider a larger Plant LED grow light.

Whether using peat pellets or rapid rooters, this method ensures a high rate of success, but it does require the purchase of a propagator and the pellets or rapid rooters.

very easy
no additional equipment required (assuming you have paper towels)
requires transplanting the seeds, which risks damage
need to ensure the paper towel stays damp, but not wet

How To Germinate Cannabis Seeds