Dosatron Fertiliser Injectors for Horticulture: How They Work and Why Growers Trust Them

Introduction

Fertigation — the delivery of fertiliser through an irrigation system — is one of the most efficient ways to feed crops. It puts nutrients directly into the root zone at the moment of irrigation, improving uptake, reducing waste, and saving labour compared to manual feeding programmes.

For many UK growers, the Dosatron fertiliser injector is the go-to solution for simple, reliable fertigation. Used in greenhouses, nurseries, polytunnels, and outdoor production systems around the world, Dosatron injectors have built a reputation for accuracy, durability, and ease of use over more than 50 years.

This guide explains how Dosatron injectors work, the different models available, and how to choose and use the right one for your horticultural operation.

How Does a Dosatron Injector Work?

The Dosatron injector operates on a brilliantly simple principle: it is powered entirely by water pressure, with no electricity required. This makes it reliable, safe to use around water, and suitable for remote locations without a power supply.

Here is how it works:

1. Water enters the Dosatron and drives a hydraulic motor (a piston or diaphragm mechanism)
2. As the motor moves, it draws a precise volume of concentrated fertiliser solution from a stock tank
3. The fertiliser is injected into the water stream and mixed thoroughly before exiting the unit
4. The injection ratio remains constant regardless of changes in flow rate or water pressure — because the motor is driven by the water itself, more water flow means proportionally more fertiliser is injected

This proportional dosing is the key advantage of the Dosatron system. Unlike fixed-rate dosing pumps, a Dosatron automatically adjusts its output to match the water flow, maintaining a consistent fertiliser concentration at all times.

Key Benefits for Horticultural Growers

• No electricity required — safe, simple, and suitable for any location with a water supply
• Proportional dosing — fertiliser concentration remains constant regardless of flow rate variation
• Easy to adjust — injection ratio can be changed quickly by turning a dial, without tools
• Compact and lightweight — can be installed inline on any pipe size with simple fittings
• Versatile — suitable for fertilisers, pesticides, disinfectants, pH adjusters, and other water-soluble treatments
• Low maintenance — robust construction with few moving parts; service kits are readily available
• Accurate — injection ratios are consistent and repeatable, supporting precise crop nutrition programmes

Dosatron Model Range: Choosing the Right Unit

Dosatron produces a range of injectors covering different flow rates and injection ratios. Choosing the right model depends on your water flow rate and the dilution ratio required for your fertiliser programme.

Injection Ratio

The injection ratio is expressed as a proportion of fertiliser concentrate to total water volume. For example, a ratio of 1:100 means 1 litre of concentrate is injected for every 100 litres of water. Common ratios used in horticulture range from 1:500 (very dilute) to 1:50 (more concentrated).

Your fertiliser supplier will specify the required dilution ratio for their product. Make sure the Dosatron model you select covers that ratio range.

Flow Rate

Each Dosatron model is designed to operate within a specific water flow rate range. Selecting a unit that is too large for your flow rate will result in inaccurate dosing; too small and it will restrict your irrigation flow. Match the model to the actual flow rate of the zone or system it will serve.

Popular Models for Horticulture

• Dosatron D25RE — one of the most widely used models in UK horticulture. Suitable for flow rates up to 2,500 litres per hour, with an injection ratio range of 0.2% to 2% (1:500 to 1:50). Ideal for greenhouse benches, propagation areas, and small nursery zones.
• Dosatron D8RE — a smaller unit for lower flow rate applications, suitable for individual greenhouse bays or small polytunnel zones.
• Dosatron D45RE — higher flow capacity for larger zones or main supply lines serving multiple greenhouses.

Browse our full Dosatron range to find the right model and accessories for your system.

Installation Guide

Dosatron injectors are designed for straightforward inline installation:

1. Install the Dosatron in a bypass configuration on your main water supply line, or directly inline on a smaller supply pipe
2. Connect the suction tube to your fertiliser stock tank — the tank should be positioned below or at the same level as the injector
3. Set the injection ratio dial to the required dilution
4. Flush the system briefly with water only before introducing fertiliser, to confirm the unit is operating correctly
5. Introduce the fertiliser stock solution and check the output concentration with an EC meter

Important: Always use a backflow prevention device (check valve) upstream of the Dosatron to prevent fertiliser from siphoning back into the mains water supply. This is a legal requirement when connected to a mains water supply in the UK under the Water Supply (Water Fittings) Regulations 1999.

Fertigation Best Practices for Horticulture

Stock Solution Preparation

Prepare your fertiliser stock solution at the correct concentration for your chosen injection ratio. For example, if your target feed solution is 200 ppm nitrogen and your Dosatron is set to 1:100, your stock solution needs to be 100 times more concentrated than the target feed.

Always dissolve fertilisers fully before use and check that all components are compatible — calcium and phosphate or sulphate fertilisers should never be mixed in the same stock tank as they will precipitate.

Monitoring

Use an EC (electrical conductivity) meter to verify the output concentration of your fertigation solution regularly. EC is a reliable proxy for total dissolved nutrient concentration and allows you to confirm the Dosatron is dosing accurately.

Check pH at the same time — most crops perform best with an irrigation water pH of 5.5 to 6.5. Dosatron injectors can also be used to inject pH adjustment acids (such as nitric or phosphoric acid) to correct alkaline water supplies.

Flushing

Always finish each irrigation cycle with a period of plain water to flush fertiliser residues from drippers, pipes, and growing media. This prevents salt build-up and keeps your system clean.

Filtration

Fertiliser solutions can contain fine particles that block drippers and injector components. Always filter your irrigation water before the Dosatron, and use only fully soluble fertilisers. Our Amiad Filters range includes options suitable for fertigation systems.

Dosatron for Pesticide and Disinfectant Application

Beyond fertiliser, Dosatron injectors are widely used in horticulture for:

• Disinfectant dosing — chlorine, hydrogen peroxide, or peracetic acid for water hygiene in recirculating systems
• Pesticide application — systemic pesticides applied through the root zone via drip irrigation
• Wetting agent dosing — improving water penetration in peat-based growing media
• Rooting hormone application — in propagation misting systems

Always check that the chemical you intend to use is compatible with Dosatron materials (polypropylene, EPDM, and stainless steel in most models) and follow all label requirements for application rates and safety.

Maintenance and Servicing

Dosatron injectors are low maintenance but benefit from an annual service, particularly if used with concentrated fertiliser solutions that can leave deposits on internal components:

• Flush the unit thoroughly with clean water at the end of each season
• Inspect the suction strainer and clean if blocked
• Check seals and O-rings for wear — service kits are available for all models
• Store the unit in a frost-free location over winter

Spare parts and service kits are available in our Fertigation System Spares collection.

Conclusion

The Dosatron fertiliser injector is one of the most practical and cost-effective tools available to horticultural growers. Its simplicity, reliability, and proportional dosing accuracy make it a trusted choice for everything from small greenhouse operations to large nursery and farm installations.

Browse our full range of Dosatron injectors and accessories online, or contact the IrriSmart team for advice on choosing the right model and setting up your fertigation programme.