Balcony Garden Watering Hack

What do you do when you want to head off on a trip for a few weeks over the summer and you don't want to find all your plants dead when you return? (Your neighbours are going away too, so no one will be around to tend that lovely hibiscus!) Easy! Using a washing-machine water valve, an electronic timer, some plastic tubes, clamps and small sprinkler heads (available from hardware or garden shops), a simple automatic watering system can be made.

You can pillage an old washing machine for its water inlet valve...or buy a new or used one from an appliance repair shop.

This valve has three 220V solenoids that control three outlets. The inlet (in the left foreground) is connected directly to a standard garden hose screw coupling. Do not use those “snap” or “quick disconnect” couplings unless you want a flood in your apartment. They are not secure if kept constantly under pressure. Be sure to use the screw-on type hose coupling like the one shown in the picture. 12mm plastic tubing is clamped to the outlets.

Crimp-on spade connectors are used for the electrical connections. Be sure to use insulated ones for safety. In fact, I would recommend mounting the valve in a plastic box and sealing it up with silicone for safety's sake! Be veerrry careful with 220V....this description is for illustrative purposes only. Where water and electricity are in close proximity, special care is needed to prevent accidents. Be sure to earth any metal parts and use a differential safety switch (ground-fault interrupter) and circuit breaker in the circuit to prevent accidents. Make sure everything is out of the reach of children too. You've been warned! Valves also come in 24V versions, which may be safer...

The other major part of the system is the timer. A simple electronic timer that allows you to set the dat and time is best. In this experiement, we set the timer to activete the valves for 2 minutes at 5.30am every other morning. This should be enough to allow the plants to cope with the hottest summer days.

Clear plastic tubing is used to distribute the water to the various plants. Small spray heads are used to slow the flood of water from the tubes. By using shallow pans, some water is retained without flooding the plants.

Here is a “bird's eye view.”

The 4 to 1 branch in the tubes: the “fat” 12mm tube is distributed to four 3mm tubes like this:

By stuffing four of the thinner tubes into the fatter tube (using a bit of quick-setting epoxy around the thin tubes to seal them), we can realise a reasonable connection. The hose clamp is applied when the epoxy is hard, to help hold everything together.

That's it! You are ready to go! The system may need a little adjustment to regulate the water going to each plant. Be sure all connections are watertight and remember your electrical safety (timers, plug boards, etc. do not like being outside...be sure to waterproof where necessary.)