Polytunnel Watering

Polytunnel Watering

Polytunnels are warm growing environments excellent for spring germination and for sustaining longer harvests well into the autumn.

However, their warmth also means that finding a quick and convenient watering solution is important.

Polytunnel Watering

Installing a drip irrigation system can be a time saving practical solution that is beneficial to plant growth. On this page I review the Irrigatia Sol C24 automatic watering solution.

About Drip Irrigation Systems

Drip irrigation systems release water at timed intervals throughout the day. This gradual release of water means that plants never dry out, and is more efficient than using watering cans (as much less water is lost through ‘run-off’).

Drip irrigation systems can work by using:

  • Seep hose
    A special hose that releases water gradually through tiny holes in its wall. These may be buried or surface mounted.
  • Drippers
    Water is released in drops from drippers positioned near the base of the plant.

Drip irrigation systems need both a water source and water pressure to work effectively. On my allotment I do not have mains pressure water, therefore I needed a solution that could either use gravity to provide water pressure, or a pump.

Polytunnel Watering - Irrigatia-Sol-C24

For my allotment I chose a solar powered automatic watering system by Irrigatia. Irrigatia systems use the sun’s energy to pump water out of water butts to irrigate plants.

I chose the system as it seemed particularly suited to allotment watering, as the solar powered pump enables it to use water stored in water butts or barrels. It is called Sol C24 because it can water up to 24 tomato plants or 20 litre pots, equivalent to about 10 hanging baskets.

Irrigatia Sol C24 – How It Works

The Irrigatia system works in a very simple way. Within the body of the unit there is a small diaphragm pump that sucks water out of a water butt or other reservoir, and pumps this water through the drip irrigation system.

The Irrigatia system is 100% powered by the sun. On the outside of the body are solar panels to harvest the sun’s energy, which is then stored in rechargeable batteries contained inside the pump unit. The sunnier a day, the more the batteries are charged, leading to the batteries providing more power to the pump. This means that the system automatically provides more water on sunny days when plants need it most.

Polytunnel Watering - Irrigatia-Sol-C24-Review-Solar-Panel

The Irrigatia Sol C24 has a night mode sensor that turns off the pump at night – not that useful on our remote allotment – but of value if the unit is in earshot of your bedroom or any of your neighbours.

What is most useful is a water level sensor that switches the pump off if it detects that the level in the water reservoir is too low – helping to protect the pump. On my allotment this has happened a couple of times already, when the water butts have run low due to hot weather. The water level sensor is positioned about 10cm above the water filter submerged at the bottom of the water storage, so that when the water level drops it is exposed to the air before the water filter is left dry.

Installation of the Irrigatia system is quite straightforward. The first step is deciding where to site the pump body with the solar panels. For my polytunnel this decision was straightforward. I sited the pumps either side of the door frame that was south facing for maximum sun light.

Polytunnel Watering - Two-Solar Units

After mounting the unit, the next step is to connect the unit to the water reservoir, ensuring that there is enough length of pipe to reach down to the bottom of the water storage. The water out tube is then connected to the pump. Like nearly all other drip irrigation systems, it requires you to create a network of pipe and drippers in a chain to water all your pots.

Polytunnel Watering - Dripper-Network

The Irrigatia Sol C24 comes with 15m of tube and 12 drippers. This was not enough for what I needed, so I purchased additional dripper extension kits.

The pipe is simply cut with scissors, and using the supplied tee joints, it is possible to make branches off the main supply tube to water each pot.

Polytunnel Watering - Dripper-With-Stake

Other accessories for the system are available as well, including lengths of hose and seep hose, an intensive care plant feeder, and a water reservoir for use with an outside tap.

Once installed, for the first few days I regularly checked the drippers to check that they were watering correctly. I also experimented with turning up and down the pump output. There are five settings available using the control knob on the side of the pump unit. For my set up the recommended mid-setting works fine.

Polytunnel Watering - Flow-Settings

I found it took 24 hours before the system was working properly, probably because it took this long for the batteries to be fully charged by the sun.

Since installing the system I am very happy with it. The unit waters every three hours, and by spreading watering across the day it seems to have helped the plants grow well. Best of all, it has saved considerable time and avoided the need of a daily visit to the polytunnel.

However, only time will tell how long the pump unit, and other components will last. Spare parts are available to buy online if need be.