Greenhouse irrigation systems. Which one to choose?

You can't rely on rain inside a greenhouse, so choosing the right irrigation system decides how well your plants grow. The short answer: drip irrigation gives the best control for most greenhouses, soaker hoses are the budget pick for raised beds, mist systems suit propagation and tropical plants, and a sensor-based automatic system pays off when you grow more than a few plants or travel. Your choice should reflect greenhouse size, the type and number of plants, and how much time you can give to gardening.

How do the greenhouse irrigation systems compare?

1. Self-watering trays and capillary mats

Self-watering tray.

The simplest method: a water compartment feeds the soil from below, sometimes through a capillary mat that releases water gradually. Watering from the bottom encourages deeper roots, and one weekly refill usually keeps all plants hydrated — excellent for small greenhouses, beginners, and plants that dislike overhead watering (like orchids).

Pros: inexpensive, easy to install, constant water supply, promotes root growth, lowers disease risk. Cons: not every growing medium works with it, capillary mats can grow algae (which attracts mosquitoes), fertiliser build-up may need occasional rinsing, and the reservoir refill is manual.

2. Sprinklers

Overhead sprinklers in a greenhouse.

Overhead tubes with adjustable nozzles, usually ceiling-mounted in greenhouses. Best for crops that tolerate wet foliage and for small transplants awaiting their final spot. They save time but need regular checks.

Pros: inexpensive, easy to install, easy to automate, effective in medium-to-coarse soils. Cons: wet leaves invite disease, nozzles clog with poor water quality, evaporation raises water use, and every plant gets the same dose — no zone adaptation.

3. Mist (fog) systems

Mist irrigation system.

Emits fine droplets on a cycle (for example every 15–30 minutes) — ideal for propagating seedlings and large greenhouses with many plants needing regular moisture. Misting also cools the greenhouse in summer and raises humidity, which tropical plants love.

Pros: automatable, cools the greenhouse, small-to-medium initial investment, perfect for propagation and tropical collections. Cons: wasteful if poorly managed, uniform coverage with no zone control, some plants dislike constant humidity, and a permanently damp canopy can breed disease.

4. Drip irrigation

Drip irrigation system.

A hose with emitters that release slow drips at the root zone, on top of the soil or buried. It scales to any greenhouse size, minimises evaporation because water goes straight to the roots, and can be fully automated. Usually pressure-fed via a pump, though gravity versions exist.

Pros: programmable per zone, the lowest water waste, adjustable emitters, works with collected rainwater. Cons: a pump needs electricity, emitters can clog, cleaning is fiddly, and rainwater reuse needs a filter investment.

5. Soaker (porous) hoses

Soaker hose.

Similar to drip but without emitters: the hose material itself is porous and continuously seeps a small amount of water into the soil. Great when you don't want to plan a layout — lay it through a raised bed and go.

Pros: cheap, easy to install, low maintenance, minimal evaporation, almost never clogs, automatable with a tap timer. Cons: no per-plant or per-zone adjustment, must lie fairly level for even flow, and it suits raised beds — not pots or mixed plantings.

Recommended for greenhouses

6. Sensor-based automatic system — GRAAS iRigator

Automatic irrigation system GRAAS iRigator.

An automatic system combines drip lines with a controller so plants get the right amount of water every time — no need to be there, or even in the country. The GRAAS iRigator goes a step further than timers: it waters based on real soil-moisture readings, runs 4 independent zones for different crops, and shows soil moisture, temperature and humidity graphs in the GRAAS app. Installation takes a few hours: run the hoses, hang the controller, connect, place the sensors, set your zone profiles.

Pros: saves the most time, frees you for plant care and harvesting, precise per-zone dosing avoids over- and under-watering, and efficient distribution lowers the water bill. Cons (honestly): the highest upfront cost of the six; automation only helps if configured properly — check the greenhouse after scheduled waterings for the first weeks; and remote control needs internet coverage.

So which greenhouse irrigation system is best?

For most growers: drip irrigation or a soaker hose for simplicity and low cost; a mist system if you propagate seedlings, grow tropical plants or need summer cooling; sprinklers only for crops that tolerate wet leaves. If you want watering fully off your plate, a sensor-based system like the GRAAS iRigator monitors soil moisture and temperature, adapts each zone, and is controlled from anywhere. Be realistic about your greenhouse size, plants and budget — then pick the simplest system that meets them.

See the GRAAS iRigator

Read the full 4-system price comparison →