Watering plants with a timer


I want make a little and simple project for my grandma. She doesn't like going out for more that a few days because she can't water all of her plants, so I was thinking of making something to water them for her.

The idea is to use some kind of electro-valve connected to the water source, and a gardening hose with small holes around all the plants. Maybe set a timer for 15 minutes very 8 hours or something like that.

It has to be really simple, so she doesn't have any troubles with it.

I plan to use an Arduino Leonardo/UNO, because I already have them without any use.

Any suggestions before I start with the design??


Which Arduino to use is not really relevant. Check the availability of the necessary valves and tubes and get that connected. The look for the needed electronics. Then choose the best fitting Arduino.

Hi, the easiest electrically controlled valve to find is one from a clothes washing machine or possibly a dishwasher. Those are driven by 120VAC (USA) or 220VAC (Europe, China etc).. These valves take a regular hose connection in (use a washing machine hose). They usually have a smaller hose output connection.. 1/2" to 3/8" you can adapt stuff.

For controlling these valves, and power in general from Arduino see the http://ArduinoInfo.Info WIKI here:

You have to be willing to connect (or get electrical help in connecting) 120V AC wiring to the valve. A good way to connect to Arduino is with a prebuilt relay board like these:

You can get these from my (self-serving) shop or on Ebay from many suppliers.

Setting a small time ON every so many hours can be done with regular Arduino timing. The exact time may drift a little over many days, but the plants won't care. If you want to control by day / hour / minute you will need a "real time clock" like one of these:

Another possibility is to use a windshield washer pump from a car, which runs on 12V DC. Lower voltage and not the concern with properly covering all the wiring connections like 120V AC.

DISCLAIMER: Mentioned stuff from my own shop...

The idea is to use some kind of electro-valve connected to the water source, and a gardening hose with small holes around all the plants. Maybe set a timer for 15 minutes very 8 hours or something like that.

Consider not attaching it to a water source but rather use a reservoir of some sort - bucket, drum, whatever; it will limit the damage you can do if there's a bug in your code. If you elevate the reservoir, you may be able to get away with gravity feed and just need to be able to control the valves.

This may be simple enough that a programmable timer from the hardware store / Home Depot etal may be enough. Still need that electrically controlled valve..

Id also give some thought to the water OUTPUT..

meaning if you are just opening a valve and letting gravity pull the water through... you are going to get different results at different spots along your 'hose'.. (different water output).. the first one will always get more..etc or maybe not enough 'pressure' to reach the last/furthest away plants..etc..

I suppose that could all be up to you though... and how you do yo set-up.. how much you want to invest..etc..

I think the reservoir idea has some merit here...
1.) gravity feed.
2.)no running 'hose' that has a value shut on it..(or scary voltage!)
3.) can use 1 BASE reservoir.. but have MANY (fish tank lines with multi lines/outputs) going to plants.. (each having a dedicated line more or less).. ensuring the 'same' amount of water gets to each plant (per se`)

maybe solenoid valve?

nice 12v walwart to power Arduino and valve...??

Thanks for all the feedback.

I'll review it all with more detail as son as I get out of work.

The reservoir idea sounds great, but maybe ill need a pump, because she has some plants attached to walls and at different heights.


Think about instead of a time, a soil wetness sensor. Then they won't get over or under watered, neither rot nor dry out. On windy days and hot days they will transpire more water and on rainy or humid days, less.

I did this cheaply and easily with a low voltage DC pump and a Baby Orangutan board (Arduino clone with integrated H-bridge). I used a cheap wall wart to power the board and the pump. I included a soil moisture sensor, but that's optional. The solution is cheap enough that you might be able to afford one per plant, but there's nothing stopping you taking a single hose round multiple pots if you can figure out how to balance the water distribution.