Recover the three vanes near the East Hall
Try the Courtyard pinwheel to trigger the theft. You need five vanes, not four. Enter the Hydro Generator and open the East Hall. In the Gardener’s Dwelling, restore the hidden door and investigate the wardrobe. Blow the ceiling fan to lift the bed, use a filled bucket to weigh down the revealed mechanism and descend to the Gardener’s Lab. Remove the Greenies’ sunglasses, clear the fight and catch the Hider for one vane. A purple Bulb lifts you back out.
In the Tool Shed, defeat the Slammer and armed Greenies, then uncover its Hider. In the Garden, start the mower to cut through the hedge. Defeat the Gobber and Greenies below, then catch the third Hider. Collect every dropped vane before moving on.
Grow the route to the Seedling Laboratory
Inspect the drinking fountain in the Tool Shed to reach the Toolshed Stairs. Keep climbing with the moving steps. In the Botany Lab, restore the missing pipe with Dark-Light and flash the three switches together to grow the large plant. Climb to the Seedling Laboratory, clear the Greenies and catch its Hider for the fourth vane. Use the seed shooter on the gem-carrying mouse while the room is clear. The Garden and Botany Lab each also have a water-and-flash flower gem.
Play the Conservatory organ
Take the upper stairs to the Conservatory and defeat the Slammers around the organ. Play it to force the last Hider out of the pipes, then quickly stun and vacuum the ghost before it hides again. The fifth vane completes the mission. For the Boo, return through the Gardener’s Lab into the Sewer and pull the first hanging red plant. This Boo is concealed in the plant; it does not require restoring a missing cloth.
Collectible checklist
Haunted Towers gems — #3 Garden, #4 Botany Lab, #5 Seedling Laboratory
Boo checklist — Sewer: Enter north of the Gardener’s Lab and pull the first hanging red plant.