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I have a practical question about a garden irrigation system I'm thinking about creating. Instead of connecting this "drip system" to my faucet which only has expensive water from the government, I'd like to connect it to a water barrel that collects rain water.

I have the current setup in mind (apologies for my programmer art): Sketch of irrigation system

A hose is running through my 4 garden beds (only two drawn). I figure the total hose length would be about 15 meters, with a diameter of I guess 1 cm (typical garden hose). I would then make holes in the hose, and connect smaller tubes. I got this idea from http://www.prettyprudent.com/2011/03/prudent-home/irrigation-system-for-raised-bed-garden-2/

The question I have would be: is the system of "communicating barrels" enough to ensure the water from the barrel reaches all the way to the end of the hose? Or would I need a pump to ensure pressure? Is there a way to calculate these things?

Thanks in advance (I haven't bought anything yet)!

  • I don't know enough to answer your question but found this question at Physics.SE that may help get you started – Jeff Lambert Jun 2 '15 at 16:27
  • If you put your tank on higher place then you don't need any kind of pump. But, how will you control the flow of water? – Rob Biehl Jul 30 '15 at 11:30
  • @RobBiehl I was thinking of a faucet that I could turn halfway or closed – Tominator Aug 6 '15 at 9:23
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There are a number of issues when it comes to running a drip irrigation system off of a rain barrel. You won't be able to use any of the emitters in the linked article. Drip emitters work better with a certain amount of pressure, usually a minimum of 10 PSI but there are some emitters and drip lines that can work with less pressure although it's common for the watering to be uneven at low pressure with more water flowing closer to the barrel than at the end of the line.

Water pressure in the barrel increases by 0.433 PSI for every foot above the emitters the water level in the barrel is so elevating it off the ground will be necessary. If you have a 4 foot barrel on a 5 foot pedestal and your raised beds are 1' off the ground you'll only get about 3 PSI of pressure and that's only when the barrel is full. To be able to run a regular drip system efficiently you'll need to have the water about 25' above the emitters.

It is doable though but you need to look for "gravity feed" drip irrigation products. These are designed to work with non pressurized water sources such as from a rain barrel.

  • Thanks for the calculations and the detailed explanation. I will have to take a look in my local store if I can find those... – Tominator Aug 6 '15 at 9:34

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