The only way to legally grow marijuana in Canada is to grow for a patient with an MMAR number. The number of plants you can grow depends on the amount your patient(s) have been prescribed. See our page on growing marijuana legally  for more detailed information on the laws for growers.
Growing Your Own Medicine
Growing your own medical cannabis can be a very rewarding experience and isn’t too difficult. A lot of information can easily be found online if you run into trouble. The main problem with growing indoors, in an artificial environment, is the potential for various invasions and diseases such as fungus or spider mites.
Begin by germinating your seeds. There are various ways to do this and different folks will swear by their favourite method. Most people sprout the seeds before planting them, either in soaked cotton or paper towel, keeping them very moist and warm for two to three days or more before putting them in soil. You can also plant them very shallowly in pots and keep them well moistened with a clear plastic or glass sheet over them to keep the moisture in. Spritz them with water regularly and keep them warm. Another method is detailed here .
As mentioned above, it is very easy to get diseases and whatnot growing plants indoors whether the light is natural or artificial. Therefore, it is important to make sure you sterilize the pots and room before starting to grow your plants. Also, be sure if you are bringing any new plants in, to keep them quarantined for a period to be sure they are disease free. Always wash your hands before entering a room. It is easier to prevent diseases by using neem oil (for example) to help prevent fungal and mite issues, rather than trying to beat back a full blown plague.
Keep a close eye on your plants daily, this is a good way to catch any problems early.
Any tap water used should be allowed to sit out for about 24 hours in open containers to allow the chlorine to evaporate off. Plants should be watered regularly but care needs to be taken not to over-water them, as this will cause the roots to rot and die. As you get to know your plants you will know when they are thirsty, or push your finger into the soil to see how damp it is.
Plants can have worm castings or other nutrients added regularly, and it is good to maintain a soil Ph level of 5.8 – 6.2. If you are using lights be careful to maintain a consistent cycle, and be sure not to put the lamps too close to the plants.
Inner leaves can be thinned, but be careful not to take off too many as this will also shock your plants. Plants can also be tied down once they reach a certain age and this will help to encourage more of the flowers to form on each plant.