Horticultural Equipment and Turnkey Horticultural Projects

Growth Support

Irrigation Systems

With over 30 years of experience in designing irrigation systems, you can rely on CMW for all your irrigation needs. Good irrigation design will ensure accurate, consistent irrigation that will deliver good results for years.

In order to provide your crops with water and nutrition, we design and install reliable and sustainable systems. We develop our systems according to your wishes and on the basis of the vast knowledge and expertise acquired through years of practical experience.

In this way, you will be at the forefront in the use of sustainable irrigation and fertilisation. In addition, our systems are linked to software that gives you direct insight into the consumption and needs of your crops. CMW designs and supplies a wide range of automatic irrigation systems to suit all crops: protected and outdoor, edible and ornamental. The design objective is the same in every case – accurate irrigation that will result in high-quality crop performance.

Some of the products we supply:

  • Overhead Irrigation
  • Drip Irrigation
  • Ebb & Flow Systems
  • Fog & Mist Systems
  • Roof Irrigation Systems
  • Irrigation Sundries
  • Irrigation System Design
  • Nutrient Dosing & pH Control
  • Recirculating Systems
  • Sterilisers, Slow sand filters & Pasteurisers
  • Substrate Control
  • Drain Control
  • Tanks & Pumps
  • Hydroponics Systems
  • UV Lamps
Accurate drain control is vital in order to ensure maximum production without wasting water and fertiliser. CMW is able to offer a range of solutions for measuring drain volume, Ec, pH, and temperature, either from a limited number of plants or for a whole section or greenhouse.

Drain measurement can be combined with devices to automatically track transpiration rates and control irrigation frequency. See case history. Where recycling of drain water is required CMW can design, supply, and install the drain system including tanks, pumps, filters, and drain water sterilisation.

Pressure compensated self-locking drip systems, which provide uniform and accurate delivery either to individual plants or rows of plants.

These systems do not drain down and so stay full between irrigation cycles. When the next watering starts, the drippers throughout the whole system start immediately. Because they are pressure compensated, drippers at every position in the system will deliver exactly the same amount of water.

CMW keep an extensive range of irrigation sundries, spares and consumables in stock for those times when you need irrigation items quickly.

In stock:

  • HP PVC pipe and fittings 10mm – 200mm
  • PVC glue
  • Flanges and flange sets
  • Non return valves
  • Drippers, stakes and leads
  • Irrigation tapes
  • Overhead irrigation nozzles
  • Pressure gauges and pressure relief valves
  • Ball valves, butterfly valves, lever valves, solenoid valves
  • Tricoflex heavy duty hose ½”, ¾” and 1″
  • Geeka connectors ½”, ¾”, 1″, 1¼”, 1½ including replacement seals
  • HDPE/MDPE & LDPE pipe and fittings
  • Compression fittings
  • LP PVC pipe and fittings 110mm – 500mm
  • In-line filters, screen filters, automatic filters, sand filters
  • Water meters

To order:

  • Hose reels, trolleys and lances
  • Dosatron injectors
CMW offers a wide range of nutrient and acid dosing systems by leading manufacturers Priva and Heron. Generally speaking, these systems are scalable to cope with everything from experimental applications designed for minimal flow to full-scale commercial situations where flow rates can be 100 m3 per hour or more.

CMW specialises in the supply of packaged dosing units which are constructed on a stainless steel frame complete with onboard computer control (or connection to remote control system), water pump, nutrient dosing, pH control, mixing tank, or mixing chamber.

UK manufacturer Heron offers a popular range of dosing systems integrated with user-friendly digital control. Available for a range of flow rates and based on either direct injection of nutrients in-line or on the mixing tank principle where the nutrients are injected into the tank.

More often than not, particularly in hard water areas, acid predosing will provide the best and most reliable way to ensure that the final pH is safely and accurately controlled. CMW can supply the automatic acid dosing system, water storage tank, and all associated fittings and materials.

CMW offers a complete Denton package from the initial assessment of the grower’s requirements to design, manufacture, installation, and commissioning, always keeping in mind the grower’s needs and budget. CMW recognises the need to produce high-quality, uniform plants to meet the demands of the competitive marketplace today.

Achieving consistent results requires accurate watering and the Denton system has consistently proved its ability to deliver the required performance. Along with ever-rising labour costs and the need to conserve both water and fertiliser, many successful growers have sought improved methods for watering and many have found the solution with the Denton system.


  • Accurate and efficient use of water and fertiliser
  • Highly uniform application levels
  • Reduced labour costs
  • Improved product quality
  • Skilled staff freed from the chore of hand watering
  • Fully automatic operation

Resulting in a high quality, uniform and easily graded product.

CMW offers the complete package for hydroponic recirculation: survey, design, and installation, or supply only where required.
  • Gutter systems
  • NFT liners
  • Sump tanks
  • Storage tanks
  • Submersible pumps
  • Circulating pumps
  • Pipes, valves, and fittings
  • Sterilisers and pasteurisers
  • Irrigation rigs
  • Drain Control
To eliminate the risk of spreading water borne pathogens through the irrigation system, especially in recirculating substrate systems, reliable sterilisation will be required.

CMW supply sterilisers based either on pasteurisation of the water by heating, or by exposing the contaminated water to UV or UV and oxidation. CMW can advise on which sterilisation method is appropriate for each application.

When it comes to the irrigation of substrates, three principle methods are in common use.

Radiation sum (RadSum) is the starting point for ensuring that the frequency of irrigation adjusts automatically to the prevailing weather. A sensor measuring light or (ideally) radiation will trigger the irrigation cycle when the amount of accumulated radiation reaches a preset level. Used well, RadSum will give excellent irrigation control. Vapour Pressure Deficit (VPD) is an indication of the difference between the humidity at the leaf stomata and the surrounding air (and therefore of the transpiration rate and need for irrigation.) Last year’s article on the subject gives more information about VPD with coir here.

Moisture measurement: Sensors embedded in the slab. Growers are divided about whether moisture sensors perform reliably and consistently. In the case of coir, it seems to be especially difficult to measure moisture content accurately. Trays containing one or more slabs are mounted on electronic load cells which record the combined weight of the growing medium, the crop and the water content. The measured weight changes continuously depending on water lost to transpiration and drain, or added by irrigation, and also by changes in the weight of the crop itself as fruit matures and is harvested. Most advisers now agree that judging the frequency and quantity of irrigation to substrates is the key to bumper crops. Used well, the systems described above do a very good job of controlling irrigation frequency.

Priva has developed an integrated solution – the Root Optimiser – which combines several technologies to ensure that both the frequency and overall quantity of irrigation are precisely controlled. The amount of water a plant needs ultimately depends on the transpiration rate. Root Optimiser calculates transpiration from all the climate information the Priva computer routinely gathers. By combining this information with the reduced weight of the slab due to actual transpiration and adjusting for the addition of water during irrigation cycles and loss of water due to drain, Root Optimiser has all the information it needs to irrigate at exactly the right time and to control the amount of drain very precisely.

Smart software filters out weight disturbances due to crop work and picking, leaving only the weight due to changes in the water content of the slab in the control algorithm. Root Optimiser settings can be made for up to 6 periods in the day, so that drain can be reduced or eliminated altogether at night. A full description of the Root Optimiser system can be viewed or downloaded in the following brochure.

CMW’s range of water storage equipment starts with 200 ltr tanks and tops off with multi-million-liter capacity reservoirs.

Pumps come in all shapes and sizes to handle water, dirty water (slurry), liquid feed, and pH modified water. Where the performance from a single unit needs to be variable, we can supply pumps that will automatically react to pressure changes and deliver the required flow precisely. When growers require more sophisticated control of their watering, a computerised irrigation rig with integrated pump and valve control, with pH and EC monitoring and dosing may be the right solution for you.

Maintaining loyal relationships

CMW’s leading position has been built on a commitment to maintaining loyal relationships.