As for your closet. The plants and their lighting should be the only thing in there. Also, venting is important. Or a fan would work great. You really need to time when you force flowering on them correctly. Because remember. Plants get 2-3 time bigger during their flowering stage. So make sure you have adequate overhead space. Flourescent bulbs are the cheapest and easiest way to veg your plants in their juvenile stages. Don't let them get too hot. And don't over water them. Only when the soil is getting dry. Push your finger into the soil up to your first knuckle. If you don't feel moisture. Water.