By Super Admin · 9/21/2026
Three things decide whether a rooftop garden lasts: weight, wind and water, in that order. Almost nobody asks about the first two.
Weight
Wet soil is heavy. A 40 cm bed of ordinary garden soil works out around 700 kg per square metre once it has rained through. Most Dhaka roof slabs were never designed for that, and the honest answer is to ask an engineer before ordering anything. A light medium of coco peat, compost and perlite comes in nearer 350 kg, and the heavy planters belong over a column line rather than in the middle of a span.
Wind
Six floors up the wind is stronger and drier than it is in the street, and it kills more rooftop planting than the sun does. Leaves lose water faster than roots in a shallow container can replace it. Screen the side the wind comes from, put the toughest species on the exposed edge, and keep anything tall where something breaks the gust.
Water
Containers on a roof dry out fast in April and waterlog in July. Every bed needs a drainage layer and a route to an outlet you can see, because a blocked one is not obvious until the slab is damp in the flat below.
Start smaller than you want to. A roof that works with twelve pots will work with forty. It rarely goes the other way.
