Irrigation solutions
Greenhouse Irrigation in Kenya
A greenhouse is a controlled environment — the irrigation system is where that control actually happens. Here's how greenhouse drip and fertigation are designed for Kenyan growing conditions.
Why greenhouses irrigate differently
Under cover, rain is no longer part of the equation. The crop's entire water and nutrient supply runs through your system, every day, for the whole crop cycle — often 4 to 12+ months for tomatoes and capsicum. That makes three things non-negotiable: reliable filtration (there's no natural flushing rain), precise emitter uniformity (one dry section shows up as a row of stunted plants within weeks), and consistent scheduling (a missed day in the hot season costs more than in the field).
Greenhouse irrigation in Kenya also has to fit the structure: lines run between benches or along raised beds, water is applied to soil blocks, grow bags or substrate, and the whole head assembly (filter, valves, fertigation) is usually compacted into a wall box or a single pipe run into the house.
The greenhouse drip setup
Most Kenyan greenhouse systems are drip-based, at two scales:
- Seedling and transplant production — tray tables or benches with 16mm drip lines and 20cm emitter spacing, fine emitters (around 0.8–2 L/h), fed from a dedicated line so seedlings get light, frequent applications.
- Production benches and beds — 16mm or 19mm drip lines (or lines with 20–30cm inline emitters) along each bed, typically one or two lines per bed depending on plant spacing; higher-flow emitters (2.2–4 L/h) as plants fill the bench.
For potted or bag-grown crops, point-source application — a dripper or micro line per pot — gives each plant an independent supply. The full component list lives under irrigation products, and the general system architecture in our drip irrigation guide.
Fertigation: the core of greenhouse growing
Greenhouse crops are fed through the water line — fertigation is not an upgrade in a greenhouse, it's the standard method. The setup: a dosing or injection point on the supply line after the filter, one or two fertigation tanks (typically NPK plus a micro/magnesium tank), and — at the serious end — an injection pump or pressure-driven dosing unit that mixes the fertiliser in proportion to the flow. Two or three tanks let you adjust the crop's nutrition through the season without changing the physical system.
Rules that matter: only use fertilisers rated for irrigation, keep the tanks clean, never store incompatible chemicals so that they meet inside the line (acid + certain phosphates will precipitate), and match the injection rate to the crop's stage — a young plant drowns in a fruiting-stage dose. Our fertigation guide covers the equipment and the chemistry honestly.
Automation and scheduling
Greenhouse irrigation runs on rhythm. A typical production house irrigates several times a day in warm weather — each cycle a few minutes. Doing that by hand is a full-time job, which is why most commercial houses use at least a timer, and increasingly multi-zone valve controllers that run benches on schedules. At the more advanced end, soil moisture or leaf sensors trigger irrigation by actual plant need rather than a clock — useful in variable seasons. Start simple (timers), add complexity only when the operation earns it.
Water source and filtration under cover
Greenhouses concentrate what your water source is bad at. Borehole water is common and usually clean, but iron and fine silt still block fine emitters — a disc or screen filter is standard, with the media size set by the emitter orifice. Rainwater tanks are popular where the catchment area (roof) is large, but tank water sits in a warm greenhouse climate, so algae growth is a real risk: a first-stage screen plus a disc filter, and regular tank cleaning. Dam or river supply to a greenhouse almost always needs media/sand filtration plus a disc stage.
Water quantity matters as much as quality: a 100×50m house in tomato production can move a lot of water in a day. The source (or tank + refill) must be able to keep up for the peak of the season — we size this in the design, and water quality testing tells you what you're dealing with before you commit.
Crops and typical setups
| Crop | Typical application | Notes |
|---|---|---|
| Tomatoes | 1–2 lines per bench, 20–30cm emitters, 2.2–4 L/h | Longest cycles (6–12 months), continuous fertigation, heavy water demand at fruit set |
| Cucumber | 1 line per row or per pot, 20cm emitters, 2.2–2.7 L/h | High water and fertiliser demand; trellised or bag systems common |
| Capsicum | 1–2 lines per bench, 25–30cm emitters | Multi-harvest over many months; steady, consistent supply |
| Leafy vegetables & seedlings | 16mm lines, 20cm emitters, fine flow (0.8–2 L/h) | Frequent light applications; high uniformity requirement |
Specifications are typical starting points for common Kenyan greenhouse layouts; final choices depend on your structure, bed size, substrate and variety.
What a greenhouse system costs
Greenhouse irrigation costs scale with house size, number of lines and benches, fertigation equipment and automation. A simple drip line + filter + tank setup for a small house is a fraction of a fully automated, multi-tank fertigation system for a commercial block — and the price difference is real and worth understanding before you choose. See the general cost drivers in our drip irrigation cost guide, and request a quote with your house dimensions and crop for a farm-specific number.
Design, installation and support
We design around the structure: where water enters the house, how lines reach each bench without cluttering the working area, where the head assembly sits, and how the system zones so one blocked line doesn't stop the house. Installation is planned around your crop cycle so we're not working around standing plants. Ongoing, greenhouse systems need a tight maintenance rhythm — maintenance service covers filter checks, line flushing and emitter inspection on schedule.
FAQ
Greenhouse irrigation questions
What is the best irrigation system for a greenhouse in Kenya?
Drip irrigation is the standard for Kenyan greenhouses — drip lines along benches or per pot, with fertigation for feeding and filtration matched to the water source. Automation (timers or valve controllers) is strongly recommended because greenhouses irrigate multiple times daily. See the drip irrigation guide for the component basics.
How many times a day should a greenhouse be irrigated?
It varies with season, crop stage and substrate, but production houses commonly run several short cycles per day in warm weather and fewer in cool, wet periods. The principle: small, frequent applications that keep the root zone consistently moist without waterlogging. A timer or controller makes the rhythm sustainable — manual scheduling this fine is not.
Can I use my borehole for greenhouse irrigation?
Yes — boreholes are a common greenhouse water source. Specify filtration to match (disc or screen, sized by the emitter orifice), confirm the yield covers peak-season demand, and check the water for iron, which can stain and block fine emitters over time. Our water quality guide covers the checks.
Do greenhouse crops need fertigation?
For production tomatoes, cucumber and capsicum, effectively yes — the growing media in bags or raised beds holds limited nutrients, and the crop is fed through the water line over a long cycle. Fertigation also makes nutrition adjustable as the crop changes from vegetative to fruiting stage. Details in the fertigation guide.
How much does greenhouse irrigation cost in Kenya?
It depends on house size, bench layout, number of lines, fertigation setup and automation. Small houses with a basic drip + filter + tank setup cost far less than automated multi-tank systems for commercial blocks. Send your house dimensions and crop for a quotation — request a quote — and see the cost guide for what drives the price.
Planning a greenhouse system?
Tell us your house size, crop and water source — we'll design the irrigation to match.