Whats the best method when you have all options ?

Hi first post, I'm looking to start my first grow and I'm free to grow outdoors in a garden or in public areas (forests etc) or indoors.

I want to grow for personal use but I would like to get as much as I can, I live in london so the weathers never great and right now its getting cooler after summer though I would like to start growing asap.
I liked threw idea of growing outside because it seems more simple and natural though with the weather and time of year it seems unlikely as an option, is this true ?
The only restriction is budget, I don't plan on creating a super farm I'm my loft or anything so whatever the most cost efficient way.is is probably best. Anyway what should I do ? Outdoorsin a greenhouse ? Indoors in a loft ? A cupboard ? A window ledge ?
If someone could recommend the best method and supplies etc I would.be very grateful.
Thanks

Too late to start growing outdoors now. And the only one who can figure out your grow is you.

Pick a spot inside that offers accessible ventilation and room. If there isn't room, buy a grow tent or two.

READ AS MUCH AS YOU CAN!

See my url..Greenhouse is the best way.IMO security and controls are much easier. You can make a very nice Greenhouse DYI style cheaply. I have iused 2"PVC and built effective and stable hoop houses. You will see a major gain in productivity and available growing options vs outdoors alone..

North Coast Growers - Friends of Green House - New Audio - YouTube

I have a cupboard that is about 3ft deep maybe 5ft high which I think I'm gonna use, my plan is to have fan in there with a light (not decided which type is best yet) and leave the cupboard door open a few inches to ventilate and cool it down a bit. Does that sound good ? The inside of the cupboard is painted white already to reflect the light, how many plants could I grow in that space and what wattage/ how many bulbs do you think ill need ? I've been trying to read as much as I can but it's hard to take it all in I think it well be easier if I learn each bit as the plants grow.
Thanks for the replies guys