Well growing in a wardrobe seem's fine (althuogh you won't be able to grow more than one plant (two max) unless you are thinking of sea of greening them. The reason for this is that you need to plant them in a large pot in order for them go grow at any kind of speed.

Because your going to be growing over winter (and I know what english winter's are like) I'd say that you want to keep the temp up rather than down. Just open the wardrobe door's for a couple of hour's a day.

When you plant the seed's keep the light's on for 24 hour's, then when they sprout cut back to 18 hour's, and then when you want to flower the plant's (If your wardrobe is only 5.5 feet tall I'd recomend 1 1/2 to 2 feet) cut back to 12 hour's ( this simulate's the end of the natural growing season & your plant's will start to flower).

Then, if your plant is female it will start to grow bud's, on these bud's will grow hair's. When these hair's go just beyond orange that is the time to harvet!

Hope this help's

P.s I am only an amatur grower & this is only a very rough guide. If you are serious about growing then you must do your research (get a book or search the web.....for hour's)