If you live where you want to grow, and intend to grow indoors, you do not need your landlords permission, nor do they need to know. As for HC's supply of Medical Marijuana, it's garbage, and trust me, you don't want it. Many of us go to the streets because "compassion" clubs charge far far too much, claiming it's due to "Overhead costs" when anyone knows, even the underground has as much, or more overhead, yet still manage to cut deals to a point of affordability.
IMO Compassion clubs, and many DG's are simply taking advantage of a lack of quality on HC's part, by charging outrageous prices to those who genuinely need this medicine (Compassion clubs), or simply using your condition as a smoke screen to legally grow their own black market supply (DG) and profit off your illness.
Neither of these options spells "Compassion" to me, but rather smells of betrayal, by those who would lie to our face and say "We care".
Go the grow it yourself rout... trust me.
Here's an example of just how much they can profit from your illness.
Generally speaking, .5g/watt of light is the average yield, some get more, some get less.
My daily limit is 18g/day, which works out to 540g/month, or 88 plants indoors.
1 1000w light per 4 plants = approx 500g (at .5g/watt yield)
Multiply that by 22 to get my total of 88 plants (4 plants per 1000w light), and you have 11,000g in a 3-4 month time frame, breaking down to 2,750g/month. 540 of which comes to me at a cost in most cases, usually $3/g, and the remaining 2,210g, or 4.9lbs they sell on the black market for black market prices again, turning an additional profit on your illness. Which where I'm from, is $2800/lb, which translates to $13,720 EVERY MONTH!!!