how to build a diy window sill box planter

Posted on
window sill garden

Gardening is an amazing way to produce trust worthy food for you and your family, but not everyone has the space to do so. Whether you’re in an apartment, townhome, or you have an unpleasant landlord, a small window sill garden will most likely allow you the freedom of farm to table meals. Perfect for herbs, flowers, or small vegetables, this is a great addition for both beginners and pros. Let’s get into these simple steps, so you can have your own window sill garden in a matter of hours!

Tools/materials needed:

  • Screws
  • Drill/screwdriver
  • Sandpaper
  • 1X4’s (length of your choice, depending on your window sill)
  • 2X4’s (length of your choice, depending on your window sill)
  • L brackets (wire or another bracket that does not require being screwed in)
  • Paint, paint brushes, ect.. (0ptional)

Step one:

Cut 1×4’s to length for the front and sides. Be sure to sand the square edges off of the 1×4’s to break the edge and highlight the horizontal planks.

window sill garden

Step Two:

Screw the horizontal planks to 2×4 support blocks.

window sill garden

Step three:

Another piece of wood was added to the bottom and then to the back of the flower box. Drill a few holes in the bottom of each box for drainage.

window sill garden

Step four: (optional)

For better aesthetics, you can add some extra pieces of trim around the tops and bottoms to add some character to the boxes.

window sill garden

Step five:

This is the fun part, paint and decorate the box however you choose, this is a great job to give to kids who want to help!

After, I recommend that you brush about three coats of spar varnish over each box to protect them from the elements, including the insides.

window sill garden

Step six:

Use L brackets underneath the window sill to attach the box. In this photo, the builder started with two brackets but later added a third for additional support.

If you are not able to attach the L brackets, try using wire or brackets that run inside the window without requiring the use of screws or nails.

window sill garden

Step seven:

This build is mounted a little lower than the window sill so the windows can still be opened up for fresh air.

window sill garden

Step eight: (optional)

Before adding potting soil and plants, you can line the box with a piece of landscape fabric to help protect the inside of the flower box from moisture.

window sill garden

step ten:

Enjoy the beauty and nutrition that is sure to follow this project!

window sill garden

Simple enough right?

This project shouldn’t break the bank or take up your entire day, sometimes the hardest part is choosing what to grow. Here is a link to point you in the direction of some good plants and herbs you can grow in these gardens, remember to do your research, ensure your seeds and soil are the best quality for you and your household.


*All pictures and plans credited to


Leave a Reply

Your email address will not be published. Required fields are marked *

Time limit is exhausted. Please reload CAPTCHA.