I did this project for a number of reasons. I have been looking for ways to bring the indoors outside and vice versa, and I also have an increasing interest in herbs. My cat Maybe likes to sit in this windowsill because it gets great light, so I decided to build something that would work with both of us!
First I cut 4 pieces of redwood to the exact specifications of the windowsill that is already in place. If you don’t have a windowsill you will need a bottom for the box and some brackets. This shelf is pine. The redwood I have for the edges is naturally distressed by the sun because it had been left outside for awhile. I like using hardwoods because they are less susceptible to water damage.
Closeup of the frame. I also pre-drilled holes on either side to attach the box to the shelf once the plants are installed.
Then I used a staple gun to attach a strip of thick gardening plastic (used for weed-block) and a glue gun to secure the edges.
Then I gave the whole thing a nice dusting of food-grade diatomaceous earth to keep any bugs at bay. Because I am using herbs for the window this shouldn’t be a big problem though, because herbs are naturally bug-repellent.
I picked Creeping Lemon Thyme (Thymus serpyllum ‘Skorpelii’) because it is listed as being non-toxic to cats, likes to dry out, has a maximum height of 2 inches, it’s very fragrant, and will spread, so I can give it a haircut every now and again for herb use. Since it has a lemon flavor the cats might like to nibble, but they aren’t going to think it’s too too tasty and since it is commonly used for ground-cover, they can sit on it!
I cut it in three strips and put a few river rocks wedged in at the end for a firm fit.
Then I screwed it in!
And it’s cat approved!