hey there! ive grown numerous times w/o a proper hose vent. ive grown huge plants, and some very proper final product. just be sure to take care to understand WHY the venting is important. for example: at least keep the area open during the "lights on" period, like keep the door open if the area has one. if its anywhere nearby a window at all at least crack the window a bit. Its important to remeber the plants use CO2 and need to have the air recycled or they cant breathe. just like a human needs oxygen, a sealed room with no vent at all would suffocate you.
wind helps the plant become sturdy, thats another reason a fan is important besides the air recirculation.
the soil wont be right either if it cant breathe properly, the air will get very humid when u water and can cause mold. ive even had mushrooms grow on the tops of the soil in potted plants indoor before. lol.
Why cant you vent it out anyways, give us details so we can help more.