If the chair has a backrest, begin by sawing it off.
Wash the drawer and the chair with furniture cleaner. Let dry and then sand any unevenness, if needed.
You can optionally use a white paint first, as a primer, especially if the wood you are painting is dark. Use a flat brush and paint with the wood grain. Let the paint dry for at least 1 hour.
Now apply a coat of the desired colour. Apply a thin coat of paint; its better to apply several thin layers. Let dry for 1 hour between coats of paint. When you are satisfied with the coverage, allow the furniture to dry completely, for 24 hours.
Staple a protective layer inside the drawer, for example a cut-out piece of a rubbish bag. This will protect the wood from moisture from the soil. Then, simply plant beautiful plants and flowers and enjoy your handiwork.
Who wouldn't want a drawer full of flowers in their garden? Or why not on the balcony? An old wooden chair and a drawer you no longer use can be transformed into a magnificent planter. Hunt at a flea market if you don't already have furniture at home that you want to upcycle. Use outdoor paint if you plan to place your planter box outside. Then simply plant whatever you like in your unique planter! Geraniums or carrots? It's up to you!