Vertical gardens and green walls: planting a facade, and committing to its irrigation.

A green wall carries plants in a mounted system of modules or pockets across the wall surface, with irrigation delivered to each plant. A green facade grows climbers from the ground or planters up a support structure. The facade is slower to cover but far cheaper, lighter and much more forgiving in maintenance.

Irrigation failure. Plants on a vertical system have almost no root volume and no soil reservoir, so a stopped pump, a blocked emitter or a power cut is measured in days before visible damage. Assured water, power backup and prompt fault response are the difference between a green wall and a brown one.

Continuous and skilled: irrigation and dosing checks, emitter cleaning, pruning, replacement of failed plants, and periodic system servicing, usually at a defined frequency with proper access equipment. A green wall is best treated as a serviced installation with an annual budget, not as a one-time landscape item.

Primarily by light, the wall's orientation and the shading pattern across it produce quite different conditions at different points, and species are zoned accordingly. Beyond light, plants are chosen for compact root systems, tolerance of a confined medium, and modest growth so the wall does not need constant cutting back.

Yes, always, and for saturated weight rather than dry weight. Modular systems carry growing medium, plants and retained water, and the load is applied to the facade continuously. Waterproofing and a drainage route behind the panel are equally essential, since a leak behind a green wall is discovered late and repaired expensively.

They provide localised cooling, some particulate capture, acoustic softening and visual amenity, particularly where there is no ground area available. They are not an efficient substitute for ground-level planting on a per-square-metre or per-rupee basis, and are best justified where horizontal space genuinely does not exist.