Germinating cannabis seeds can be done easily several ways in several different mediums from regular dirt and potting soil to special peat pellets and plugs pre-soaked in rooting hormone. The first step is to get high quality seeds from a reputable company. We recommend beginners start with ILGM based on their selection and professional support. If you are looking for complete beginner grow kits, A Pot For Pot has a variety of options for any size grow.
Here are the keys to high germination rates:
Soak your seeds in water. The cleanest water you can find - whether that is bottled water, distilled water, or tap water. Some people add a couple drops of hydrogen peroxide in 1cup/240ml of water. Drop into a cup with water and soak for a minimum of 6 hours, maximum of 32 hours. Personally I do 12 hours. Seeds can drown if left for too long.
Place in medium: either directly into your dirt/pellets/rooters 1/4 inch/6mm or in between a wet paper towel, cover (preferably in a humidity dome, but a bag or even cut a bottle in half, or if in pots cover with plastic/cling wrap), and place in a warm place. Ideally you would have these in a humidity dome on top of a seedling heat mat set to around 75F/24C degrees. On top of a fridge or dryer also works - you want a warm but not hot place.
If using paper towel method, transfer into dirt/pellets/rooters once you see root tail come out from seed. Make sure to put with white root tail DOWN, not up!
Keep seedlings in high humidity dome/cover as they come out of the soil. Spray once a day with water. You do NOT need to give any nutrients with spray or watering, though you can add a drop or two of rooting hormone if you'd like.
In 1-2 weeks they will have roots and be big enough to transplant into a larger container! The first set of leaves are smooth and oval, but once you have the second set of real leaves its time to move up! You will start giving nutrients at week 2-3 depending on your medium/soil.
Notes for AUTOFLOWERS:
Start autoflower seeds in their final grow pots. Some autoflowers are known to switch to flower too early if there is stress like transplanting. If possible, put seeds directly into their final growing pots (typically 2-7 gallons)
Notes for OLD SEEDS:
Seeds can last a very, very long time when stored in a cool dry place. Sometimes older seeds are harder to germinate due to their harder outside shell.
Before soaking in water, gently scuff the outside of the seed using fine grit (ie 500) sandpaper. Some growers line a small box (like a match box) with the fine grit sandpaper and shake the seed around in there for a minute.