Great question! I've had a couple of enclosed tent setups and learned that some air exchange is just as important as air movement. An oscillating fan inside helps keep the stems dry and strengthens them, but you still need to pull stale, humid air out and bring fresh air in. On my closet grow room I installed a small inline duct fan hooked up to a vent that leads into another room and cut a passive intake near the floor. Running the exhaust fan on a timer for 15‑20 minutes every hour keeps humidity and temperature in check without making the room drafty. If odour is a concern you can add a carbon filter on the exhaust side. Combining that with a gentle clip-on fan blowing across the trays kept my microgreens happy and mold free.