Greenhouses technology
A greenhouse is a machine for controlling conditions. Most are only half switched on.
The cover traps heat and keeps rain off — but without measurement and control, it also traps humidity, starves the crop of CO₂ and cooks flowers at midday. Greenhouse technology closes that loop.
About greenhouses farming
Kenya has thousands of polythene greenhouses growing tomato, capsicum, cucumber, herbs and cut flowers. The structure is usually sound. What goes wrong is inside it: afternoon heat above 32 °C that aborts flowers, overnight humidity above 85 % that breeds botrytis and mildew, and irregular watering that causes blossom end rot.
Every one of those is a control problem. The house changes faster than a person can respond, so the response has to be automatic — driven by sensors in the crop, not a worker’s guess.
The technology stack
Greenhouses technology, layer by layer
Climate
- Staged extractor fansStage up on temperature, humidity and CO₂, with at least one variable-speed bank to avoid swings.
- Circulation fansBreak the still, humid layer on the leaf overnight and help pollen release.
- Motorised vents and shade netRoof or side vents on 24 V linear actuators; shade net to cut the midday peak only on the hottest days.
- Temperature & humidity at two heightsAt crop height and high in the house — the difference tells you whether air is moving.
- CO₂ sensorLets extraction run for air, not just heat.
Water & nutrients
- Zone drip irrigationNormally closed 24 V valves on a manifold, one soil probe per zone, pulses sequenced one zone at a time.
- FertigationDosing pumps and A/B stock tanks with inline EC and pH.
- Tank level monitorLow tank raises an alert instead of silently skipping a watering.
Crop intelligence
- Fixed crop camerasOne per zone, same frame daily, analysed for mildew, pests and stress.
- Ground inspection droneDrives the rows and photographs under the leaves, where pests start.
- Greenhouse controllerIP65 cabinet that holds the schedule locally and resolves conflicting goals in a fixed priority order.
Target ranges
The numbers we keep greenhouses inside
General ranges. Your crop, variety, altitude and agronomist set the final values.
| Factor | Target | Why it matters |
|---|---|---|
| Day temperature (fruiting crops) | 21–27 °C | Above ~32 °C flowers abort |
| Night temperature | above ~15 °C | — |
| Relative humidity overnight | below ~85 % | Disease threshold |
| CO₂ in daylight | ≥ 300 ppm, ideally near 420 | Below 300 ppm growth is CO₂-limited |
| Extraction capacity | ~3 m³/min per m² floor | About one air change a minute in a hot climate |
| Inlet vent area | ≥ 1.5× fan outlet area | Without inlets the fans move little air |
Questions
Greenhouses: FAQ
Can you automate a greenhouse I already have?
Yes — that is the usual job. We keep the structure, the main and the drip lines and add sensors, valves, fan control and a controller.
Can a greenhouse run on solar?
Sensors, valves and the controller are low-voltage DC and easily solar-powered. Extractor fans are the real electrical load, so the array is sized against the fan duty.
Other farming environments
Start with a walk around your farm.
The first conversation is a site visit: we walk the farm with you and understand what you grow or keep and what is going wrong. No cost, no commitment. Buy outright, lease, or pay as you go by M-Pesa.