Newbie Grow Box - Ventilation Solutions

Hello! I'm a newbie, just started growing. I have a grow box set up in a wardrobe lined with fire blankets and mylar, and one 400w hps and reflector, planning on getting a couple of led lamps, and I have a 6" fan as well.

I know I will get a lot of stick for this but traditional ventilation is out of the question. I don't have permission to cut up the fitted wardrobe. I do live in quite a cool climate. There is a half centimetre gap between the doors which lets in some air. I have a plan which involves placing the fan on floor level, in front of the doors, so that the fan can suck some cool air through the doors and at my plants. Do you think this will provide adequate ventilation?

I read that for a 400w bulb, just opening and closing the doors a couple of times a day will do. Is this true? I should also mention it is quite a large wardrobe with plenty of space for heat to rise.
I am also considering propping the door open slightly to let in more air.

Has anyone else tried getting around ventilation in non traditional ways? How did you get along?

Hey Miss Grow, Welcome to RIU.

How big is this wardrobe and more importantly how big is the grow box? A 400w hps, like any hps puts out a lot of heat and in a small space will get hotter and hotter without extracting the hot air.
You could consider a small LED light of a good quality or a DIY Cree Cob light which would vastly reduce the wattage you use and the heat they create. Or use CFL bubs or strip lighting, all those would be better in a small area.
You also have to think about air exchange as far as the amount of Co2 which is vital for a plant to grow. There are DIY methods of creating Co2 in the threads on this site as well as others and also things you can buy to add Co2.
A lot of people with big set ups have a sealed environment, they add Co2 and use Aircon to cool the area but I suspect this would be incredibly hard to do in a tiny space.
Then you also have to consider the smell and how you control it.

You may have to revise your plans somewhat. Sorry that's not the answer your looking for. Its going to come down to size of area but since you are planning on a 400wHPS I cant think of a good way to control the heat from one without extraction.
As an example I use one in a 1.2mx1.2mx2m tent for vegging and without my fan extracting heat the temps would be out of control very quickly and the plants would die soon.

There may be ways to do what your doing but I think you would have to go a different route than a 400hps.

Good luck.
Check out the stealth grow threads on here and check out the micro grow cabs all over the internet.

Thanks for being honest. Odour control is not a problem as the house already stinks of weed and cats xD. Maybe I should rethink the ventilation. I thought because it wasn't a completely sealed environment, ventilation wouldn't be such an issue. The wardrobe is 50cm by 120, and reaches the ceiling. Seems tiny now compared to your tent. I figured the height would help a lot.

I might try what I've explained and let yous know how it turns out. I'll measure the temperature with the fan. I won't put any plants in unless I'm sure it's OK.

If the temperature is too high, I guess I'll have to cut into that wardrobe. I think you're right, I underestimated how important ventilation is. I know how hot that lamp gets and it scares me.

Thanks, I think you've answered my question