at home drip irrigation: questions!

Asked May 26, 2013, 1:56 PM EDT

Hi!
I have 3 questions about the initial setup of the irrigation system at my house (this is for an above ground drip line setup starting from an outdoor faucet, and including a timer):

1) On the CSU extension page, it says that for an outdoor faucet, the order for head assembly is: backflow preventer, filter, and then pressure regulator. Where would an automatic hose timer fit into this set-up? Do I just install the timer first in the setup and then put this whole series of items after the timer, or does the timer go 'in between' some of the listed parts? (e.g. Is it backflow preventer first, then timer, then filter, then psi regulator? Or some other configuration?)

2) Is there a rule of thumb about when to just use drip lines with emitter holes vs. when to additionally use various bubblers/sprinkler-tops/pop-ups/emitter spouts? Related: Are emitter holes on drip line tubing sufficient to water perennials, or are emitter spouts (or bubblers, etc.) additionally recommended for each plant? (I saw the part of the CSU extension webpage which talked about using two 0.5 GPH spouts for each perennial, but I am not understanding why the emitter holes are not sufficient for delivering water to each plant - and if they are too small to deliver the correct amount of water, then what are the emitter holes for? Is the idea that emitter holes on their own do provide a water drip, but that this would only be enough for really small plants so we need to supplement the emitter holes with actual emitter spouts for larger plants and shrubs?).

3) If I use tubing with emitter holes every 12inches, can I also put a sprinkler emitter at the end - will there be enough pressure to power the sprinkler emitter given the holes in the tubing every 12 inches?

Thanks! - Sarah

Douglas County Colorado irrigation and water management drip irrigation horticulture

1 Response

I'm assuming that you are referring to the following fact sheet on the "CSU extension page":

http://www.ext.colostate.edu/pubs/garden/04702.html

The fact sheet has some answers to your questions. The following answers are numbered according to your question number.

1. The hose timer can be installed before the backflow device and other components. So the hose timer will be the first component that attaches to the outdoor faucet.

2. I'm guessing that you are referring to drip lines with built-in emitters when you mention "emitter holes". The important thing is to know the flow rate of each emitter or any other spout. Any emitter or spout should be sufficient, as long as you run the irrigation system long enough to apply the required volume of water. The important consideration in selecting emitters is to match the flow rate with the right length of irrigation time. In the case of your example, if you have 2 emitters per plant with each emitter having a flow rate of 0.5 gallons/hour, the plant will receive 1.0 gallon of water (0.5 gal/hour x 2) if you run the drip system for 1 hour. If you need to apply 2.0 gallons to the plant, then you will need to run the system for 2 hours. You can look at the link given above for some estimates of gallons required for different plants, under the section "Operating the System". You may have to adjust the irrigation time to get the right volume of water, depending on the flow rate and the number of emitters per plant. To avoid very long irrigation times, you could spread out the irrigations throughout the week (2 or 3 times per week with shorter irrigation times, for example).

3. Sprinklers require higher pressures than drip emitters. Putting sprinklers in the same line as drip emitters is not recommended. There may not be enough pressure to properly operate both the drip emitters and sprinklers at the same time.