Auto-watering

The system distributes water via aquarium tubing to individual plants or containers. It is driven by mains water pressure.

The mains water is controlled by a water-inlet solenoid valve salvaged, with its feed hose, from an old washing machine. The valve, in its turn, is operated by a mains-operated timeswitch.

My valve is mounted on an insulated board and is covered by a plastic cover made from a small plastic box which protects the electrical connections from accidental contact with people or splashes. The connectors are normally spade connectors, and suitable prepared wires may be found in the washing machine.

It is prudent to earth the mounting of the valve and any exposed metal parts used, as would be the case in the dishwasher or washing machine from which the valve came.

The water outlet from the valve is reduced to a suitable diameter for the aquarium tubing by the barrel of a plastic disposable syringe of 5 ml capacity. The fitting where the needle normally goes may be widened at its tip by heating in a flame and pressing onto a hard surface. This will improve the grip of the tubing.

The aquarium tubing running to the watering site should be fitted at its highest point with a T joint to which is connected a bicycle inner-tube valve of the Schräder pattern and which points upwards. This is closed by the water pressure, but opens when the water ceases allowing ingress of air and draining of the system.

This is to help alleviate the problem of algae build-up in the tubing exposed to sunlight.

From there on the water is fed, by a series of T joints and 4-way joints (available from aquarium specialists), to the plants or containers.

Flow is regulated and made even by using ¾ No 10 woodscrews (brass) screwed into the open end of the tubing. These allow adjustment of water flow by screwing them further in or out, and also allow you to wire or peg the termination into position in the container.

The timing is not critical and will usually correspond to the minimum possible on an electro-mechanical timer, any excess flowing to waste.

The system is constantly adaptable whilst in use, as connectors and tubing may be added or removed as the occasion demands.

At the end of each season it will be necessary to clean the system to remove any algae build-up, and this can be effected by dismantling and soaking the tubing in a bleach solution followed by a thorough flushing.

John Williams