Climate8 min read
Getting your plants through a Pakistani summer
Six weeks of 45°C, load shedding and dry wind is the hardest test a plant collection faces here. What actually works.
May and June in the Pakistani plains combine three stresses that compound: extreme heat, very low humidity, and hot dry wind. Add load shedding — which turns an air-conditioned room into a sealed hot box within an hour — and you have conditions that will kill an established plant in days rather than weeks.
The good news is that everything that helps is cheap and simple. Almost none of it requires equipment.
Move plants before the heat arrives, not during it
A plant that has spent the winter in a bright window will scorch badly if it is still there in late May. Move heat-sensitive foliage — aroids, ferns, calatheas — back from south and west windows in April, before the worst arrives, so it acclimatises gradually.
The same applies in reverse. Anything moved from shade into full sun during a heatwave will burn within two days. Acclimatise over two weeks, increasing exposure by an hour or so at a time.
Shade cloth is the highest-value thing you can buy
A few metres of 50% shade cloth over a balcony, terrace or rooftop collection transforms survival rates. It cuts leaf-surface temperature substantially, reduces water loss, and stops the leaf scorch that turns foliage papery and brown at the edges.
For a rooftop cactus and succulent collection, 30% is usually enough. For anything tropical outdoors, use 50%. It costs very little and lasts several seasons.
Water early, and water the soil
Water before 8am. Watering in the middle of the day means most of it evaporates before reaching the roots, and water sitting on leaves in strong sun causes scorching. Evening watering is second best — acceptable, though it leaves foliage damp overnight, which invites fungal problems during monsoon humidity.
Water the soil, not the plant. Overhead watering in summer wastes water, marks leaves, and does nothing useful.
Mulch every pot
A two-centimetre layer of gravel, bark, coco chips or even dry leaves on the soil surface of a pot dramatically reduces evaporation and keeps the root zone cooler. On a terrace in June this can halve how often you need to water.
For cacti and succulents, use gravel or coarse grit rather than organic mulch — it gives the same benefit without holding moisture against the stem.
Group plants together
Plants transpire constantly, releasing water vapour from their leaves. A group of ten pots standing close together creates a measurably more humid pocket of air than ten pots spread around a terrace, and every plant in the group benefits.
This is far more effective than misting, which raises humidity for perhaps ten minutes and is otherwise mostly a way to spread fungal spores between leaves.
Get pots off hot surfaces
A dark plastic pot standing directly on a concrete roof or a tiled terrace in June can reach temperatures that cook roots outright — the surface is far hotter than the air. Roots die, the plant wilts despite wet soil, and the owner concludes it needed more water.
Raise pots on feet, bricks, a wooden pallet or a slatted bench so air passes underneath. Where you can, use terracotta rather than dark plastic: it is porous, and evaporation through the clay wall keeps the root zone several degrees cooler.
Stop feeding in the worst of it
Most plants slow or stop growing above about 38°C — they are not growing, they are enduring. Fertiliser applied to a plant that is not growing does not get used; it accumulates in the soil as salt and burns the roots.
Suspend feeding through the peak of the heat and resume once temperatures ease and you see new growth again, usually from late September.
