Dhaka Rooftop Gardening for Apartment Residents — Month by Month
A Dhaka rooftop garden is a fundamentally different practice from any temperate-climate gardening guide, and most of the imported guidance fails specifically in the July-September monsoon and the April-May pre-monsoon heat. This is a month-by-month calendar for a shared-rooftop apartment gardener working with 4–20 containers, drawn from what actually survives multi-year cycles in inner-Dhaka conditions.
Container and setup basics
Before the calendar, three fundamentals that determine whether anything works:
- Container size dictates yield. For fruiting plants (tomato, chilli, brinjal) the minimum useful pot is 12 inches deep; below that, roots run out of thermal buffering by April and burn in April heat. Leafy greens are more forgiving.
- Drainage matters more than watering. Every container needs a raised base (bricks or plastic feet) so water drains freely during monsoon. Waterlogged containers kill plants faster in Dhaka than any pest.
- Soil mix. A working Dhaka rooftop mix: 40% garden soil, 30% compost or vermicompost, 20% cocopeat or coir, 10% coarse sand. Add neem cake at 100 g per 15 kg soil as a preventive pest layer.
Month by month
January
Cool and dry, one of the two best growing months. Days 22–26°C, nights 12–15°C.
- Plant: tomato seedlings (transplant), coriander, spinach, radish, carrot, beetroot, cauliflower, cabbage.
- Do: prune existing plants, refresh top layer of compost, check container drainage.
- Avoid: heavy fertilising — cool roots do not absorb fast.
February
Still cool, warming toward month-end.
- Plant: chilli seedlings, brinjal, bean varieties, more leafy greens for succession.
- Do: install shade-cloth support frames — you will need them in six weeks. Start seed trays for summer crops indoors.
- Avoid: transplanting delicate seedlings after 22 Feb; the heat begins to bite.
March
Warm days, still cool nights. Growth acceleration.
- Plant: last window for cool-season crops. Start bitter gourd, cucumber, pumpkin seeds in trays.
- Do: mulch heavily on all containers — 2 inches of dry leaves, straw, or coir. This is not optional in Dhaka; the mulch layer determines summer survival.
- Avoid: unnecessary root disturbance.
April
Peak heat begins. Daily highs 33–37°C, low humidity.
- Plant: only summer-hardy varieties (kangkung / water spinach, molokhia, drumstick, okra, chilli, brinjal).
- Do: install shade cloth (30–50% shade) over all containers by mid-April. Water twice daily — early morning and after sunset. Do NOT water midday; the leaf-scald from wet foliage in hot sun kills mature leaves.
- Avoid: repotting, pruning, transplanting. Plants are in survival mode.
May
Peak heat plus first pre-monsoon storms.
- Plant: hold. Focus on maintaining what is there.
- Do: strengthen container stakes for the coming storms. Every year rooftop tomato and chilli plants get destroyed in a mid-May Kalbaisakhi that nobody prepared for. Move small containers to sheltered corners the night a storm is forecast.
- Avoid: fertilising during heat waves — root uptake is compromised.
June
Monsoon arrives, humidity 85–95%.
- Plant: monsoon crops — okra (dherosh), amaranth (lal shak), yardlong bean, ridge gourd, sponge gourd.
- Do: check every container’s drainage weekly. Standing water = root rot within 5 days. Elevate containers on bricks if they sit directly on the roof surface.
- Avoid: overhead watering — the rain does that. Container spacing matters now for airflow.
July
Peak monsoon. 500-700 mm of rain possible in this month alone in Dhaka.
- Plant: succession-plant amaranth, kangkung, and molokhia.
- Do: fungal watch. Downy mildew, powdery mildew, and root rot are the peak-monsoon killers. Neem oil spray every 10 days on all foliage as preventive. Prune congested leaves for airflow.
- Avoid: leaving containers waterlogged. If a container fills to the brim after a heavy storm, tip it partially to drain immediately.
August
Monsoon continues. High humidity, waterlogged roof surfaces common.
- Plant: hold.
- Do: continue fungal preventive. Check for stem borers on okra and brinjal (the two most-attacked crops in Dhaka summer). Watch for whitefly on tomato and chilli.
- Avoid: heavy nitrogen fertilising — attracts sap-sucking pests.
September
Monsoon tapering. Warm and humid.
- Plant: start seed trays for winter crops. Papaya seedlings can go into large pots now.
- Do: post-monsoon container check — replace any that cracked, restore mulch that washed away, top-dress compost.
- Avoid: complacency — a late-September storm can still destroy taller plants.
October
Rains largely done, days still warm. One of the two best growing windows.
- Plant: tomato, cauliflower, cabbage, beans, carrot, radish, spinach, coriander, lettuce.
- Do: aggressive planting. This is the window when almost everything works.
- Avoid: over-planting one container — thin seedlings ruthlessly. Half-half thinning doubles the yield of each surviving plant.
November
Cool and dry. Optimal for leafy greens and cool-season fruiting.
- Plant: succession-plant everything from October. Add peas, broccoli, kohlrabi.
- Do: rig frost cloth if you have any tender plants — Dhaka occasionally dips to 10°C in December.
- Avoid: over-watering — cool weather means slower evaporation, and root rot returns in cool damp conditions.
December
Coldest month. Days 22–24°C, nights 10–14°C.
- Plant: continue succession leafy greens. Start planning next year’s tomato and chilli varieties.
- Do: compost prep — collect leaves, kitchen scraps, and cardboard for a new compost batch. Fresh compost will be ready by March.
- Avoid: seed-starting for warm-season crops until mid-January.
Where to buy in Dhaka
- Nurseries. Agargaon nursery cluster is the largest and cheapest for pots, soil mix ingredients, and mid-sized plants. Uttara Sector 6 has smaller nurseries. Manikdi has bulk soil and compost by the sack.
- Home delivery. Multiple Facebook-based nurseries deliver in Dhaka; expect 25–40% mark-up over Agargaon prices.
- Seeds. Chief Farm Care and similar shops in Farmgate carry BADC seeds; Lal Teer packet seeds are available in most grocery stores.
- Fertiliser and neem inputs. Farmgate agriculture-supply shops. Neem oil (real Ayurveda-grade, not diluted) around ৳600 for 250 mL.
The three failure modes to plan for
Almost every Dhaka rooftop gardener fails on the same three things in the first year:
1. Under-sized containers. A 8-inch pot cannot hold a tomato plant through April. Buy larger than you think you need.
2. No monsoon drainage plan. Containers sitting on the roof surface waterlog. Bricks under every pot.
3. April watering rhythm. Twice daily, early and late, never midday. Get this wrong in April and the plants that survive January-March all die in one week.
Fix these three and rooftop gardening in Dhaka becomes a genuinely rewarding practice — ~2 kg per month of fresh greens and 4–8 kg of vegetables over the year is realistic from a 15-container setup.