Iron Air Conditioner Security Grate
In the city you will often see window air conditioners with iron grates around them to prevent would-be thieves from pushing in the air conditioner and climbing through the window. These grates are typically just the right size to sit over an outdoor window well. They add some security, but also provide a flat surface on which to place a planter or potted plant. Secure them to your house, using metal hinges, and place a piece of clear Plexiglas over the top to form a flat surface for setting pots and planters.
A window well cover can be constructed out of lattice and used as a miniature arbor. Opt for plastic lattice rather than wood to prevent attracting termites, which will spread to your house. Construct the lattice, using plastic lattice frame material. Make a three-sided box that will fit over the top of your window well and stand 2 to 3 feet high, depending on how much room you have. Train a potted grapevine or honeysuckle to grow up the side of the lattice work, keeping the pot in the window well, hidden inside the lattice box.
Clear Plastic Herb Garden
If you must use a generic clear plastic bubble-style window well cover, consider using it to your advantage. Place a few window-box planters or pots of herbs inside the bubble, and let the plastic cover act as a greenhouse for your herb garden. This works best if your window well is situated on a south-facing wall in the northern hemisphere and receives a substantial amount of sunlight through the afternoon.
DIY Wooden Window Well Cover
Last but not least, you might consider making a do-it-yourself wooden window well cover. Structurally, it should be similar to old-style wooden basement doors. Construct your window well cover with a slanted top so it can be opened for ventilation if need be. Build a ramp-shaped frame out of 2-inch by 2-inch lumber. Cover the frame in plywood, and wrap the plywood in vinyl for durability. Finally, cut a hole in the wood and vinyl and install a small slot-style attic vent that you can open for ventilation. Secure the cover to your home with hinges so the entire cover can be swung out of the way in case of emergency or if you need to make repairs.