Railing and small-space planters
A garden on every balcony.
Railing planters attach to the outside or top of a balcony rail and are the single biggest space multiplier available to a balcony gardener. Most hang on steel hooks that clamp onto rails between 3 cm and 6 cm wide. Measure your rail width before buying, and confirm the load limit with your landlord or building manager before filling multiple boxes.
Plastic railing boxes are light, frost-resistant, and available in self-watering versions that cut daily watering on sun-exposed rails. Terracotta looks beautiful but adds significant weight and dries out fast, better used at floor level or on a short, sheltered run of railing.
Window boxes on wall brackets are a second option when your rail is too thin or too rounded for clamp hooks. Anchor fixings into masonry rather than render, use a liner to protect the box from repeated wetting, and leave drainage gaps at the base.
On a very small balcony, stackable tower pots and tiered shelf planters stand on the floor and multiply vertical planting area without any railing attachments. Combine them with railing boxes to fill every horizontal plane in the space.