Do vertical planters and wall gardens actually work?

The physics is against vertical growing and no amount of design solves it. Compost volume per plant is small, evaporation from a vertical face is high, water runs down rather than soaking in, and the top of the system shades and starves the bottom of it. Systems that succeed are the ones that accept those constraints rather than hiding them.

Safety

Step by step

1. Decide what you want from it — crop or appearance.For a crop, trained climbers and stacked pots outperform everything else. For a green wall effect, pocket systems and living walls look better and produce almost nothing edible.
2. Work out the watering before you buy anything.Hand watering a vertical system is genuinely difficult: water runs off the surface, the top drains into the bottom, and the middle gets nothing. Assume you will need a drip line on a timer for anything above about four rows.
3. Leave an air gap off the wall.Mount the system on battens with a drained cavity behind, so water never sits against the masonry. A permanently wet panel fixed flat to a house wall causes internal damp and rots render, cladding and pointing.
4. Fix into masonry with rated fixings.A planted, irrigated system is heavy and it is heaviest when watered. Use the same standard you would for a hanging basket bracket, at every fixing point, into solid brick or block.
5. Plan for the light gradient.The top of any vertical system gets more light and dries fastest; the bottom is shaded and stays wettest. Put drought-tolerant plants at the top and shade-tolerant ones at the bottom, rather than the same plant throughout.
6. Feed constantly.Small compost volumes with water running through them lose nutrients fast. A dilute liquid feed at every watering through the growing season is the regime that works — the alternative is a system that looks good for six weeks.
7. Choose plants that suit small root volumes.Strawberries, cut-and-come-again salad, herbs, sedums, sempervivums, small ferns, ivies, heucheras and trailing bedding. Not tomatoes, courgettes, brassicas or anything with a substantial root system.

Tips

• A freestanding vertical frame, rather than a wall-mounted one, avoids every damp and fixing problem and can be moved to follow the light.
• Rotate stacking towers a quarter turn each week or the shaded side never performs.
• On a rented property, freestanding is also the only sensible option — wall systems leave fixing holes and often a stained wall.

Common mistakes

• Fixing a fabric pocket planter directly to a house wall — It stays wet permanently against the masonry. Render blows, pointing decays, and in a solid wall the damp comes through inside.
• Expecting a crop of vegetables from a pocket system — The compost volume per pocket is a fraction of what a vegetable needs. Salad, herbs and strawberries are the realistic list.
• Watering from the top and assuming it reaches the bottom — It reaches the bottom as runoff without wetting the middle. Each level needs its own water, which is why drip irrigation is close to essential.

Alternatives

• Stacked or tiered pots: A series of proper pots on a frame or a central pole. Each holds enough compost to behave like a normal container. Reliable, easy to water individually, and the best starting point for edibles.
• Gutter or trough systems: Lengths of guttering or shallow troughs fixed at intervals up a wall or a frame. Excellent for cut-and-come-again salad, strawberries and herbs. Water each run separately and drain the ends properly.
• Fabric pocket planters: Cheap and visually effective for a season with tough, small plants. They hold very little compost, dry out in hours in sun, and are permanently damp against whatever they hang on — which is why they should never be fixed flat to a house wall.
• Stacking tower planters: Interlocking modules with a central watering channel. Genuinely good for strawberries and herbs, provided you rotate the tower regularly because one side always gets far more light.
• Trained climbers on a frame: The oldest vertical growing method and still the most productive. Runner beans, climbing French beans, cucumbers, squash and cordon tomatoes on a frame or wires give a far bigger crop per square metre of ground than any modular system.
• Irrigated living wall: A modular system with a pump, reservoir and timed drip line. This is the only version that reliably supports a dense mixed planting, and it is a permanent installation with a running cost, not a weekend project.

Questions people ask