Drip irrigation insanity!!

[Jeff Sheltman]

So I'm trying to design a irrigation system for my garden thi spring. My garden will be 25' x 10'= 250 sqr ft. I would like to stick to soaker hoses. I get 500gph from the spigot. Ive read so much about designing that it seems that most websites contradict each other. right when I think I have it figured out another variable is thrown out there. My plan was to use 1/2" tubing, then a website said to use 3/4". One site said it would be fine to run everything on 1 zone but another said 2 zones would be best too reach the furthest point of the garden. So my question is what size would be best to use as my main line? And should I split my garden into 2 zones? Here I have submitted a layout of my garden, hope it helps. sorry the lines are so shaky, I've erased and redrawn the lines half a dozen times.

 

[alp]

Welcome to the forum, @Jeff Sheltman !​

 

[Jeff Sheltman]

thank you. hope to learn alot and share this seasons gardening antics.

 

[IssMai]

Following this thread and also new to the forum. Tried to set up an indoor drip system for my seedlings last week because I had to travel unexpectedly...after drenching myself, the dining room floor, knocking a bunch of delicate plants over, and getting zero water where I wanted it to go I finally settled on paying the pet sitter extra to water the seedlings by hand :-P I want to set something outside this spring and hoping it goes a bit smoother.

 

[alp]

Following this thread and also new to the forum. Tried to set up an indoor drip system for my seedlings last week because I had to travel unexpectedly...after drenching myself, the dining room floor, knocking a bunch of delicate plants over, and getting zero water where I wanted it to go I finally settled on paying the pet sitter extra to water the seedlings by hand :-P I want to set something outside this spring and hoping it goes a bit smoother.

So much for automation. LOL!

 

[DirtMechanic]

I would run everything around the perimeter in grey 3/4 which should equal your supply and avoid sun damage, and also tee a bunch of screw in quick disconnects so the local hoses can easily be policed up when not in use or reconfigured as your plantings change. The 3/4 is necessary for orifice sizing so you have sufficient pressure. For example 3/4 would allow for 24 1/32 holes, which adds up to 24/32 or 3/4. Or 48 1/64 holes..you get the picture.

You need a good filter for drip emitters or they clog. You need a good timer for the sprayers. A solar panel battery setup would be cool. Its easy to overwater though. I have started seeing apps that track local rainfall and tell you when to water but cannot tell you if anyone has been brilliant enough to connect the dots and make a reactive smart sprinkler yet.

Anyway, the quick disconnects are great ways to customize and maintain parts without shutting down the system. I would absolutely use a feeding system of some sort, for medicine and fertilizer and ph control ease of use.

 

[Jeff Sheltman]

I just now noticed your response DirtMechanic, sorry it took so long... First I'm not in the habit of questioning a suggestion or anyone's knowledge on a particular subject when clearly i am not. Since I wrote this i plugged away on GPH ,GPS and PSI equations and your figures are the first I've seen. Again no offence, I'm still straightening all this out in my head. The last thing I read from one of the hundred sites I trolled was that since I have a GPH of roughly 500 that I could run up to 500 1gal emitters running off a 1/2" main line. Now my idea was to run roughly 150' of 1/2" PE tubing with a maximum of 40 1gal emitters ran off of short lengths of 1/4" PE. Its clear you know more than I do about this, but is there a reason this configuration shouldn't work? thanks for letting me bounce ideas off you.

 

[DirtMechanic]

Frankly, I just use orifice sizes and add the fractions to arrive at the needed or I should say possible supply because it is so easy. If known, flow rates are just a sum of numbers to the same end. I suggest 80% of supply capacity as a limit to maintain some pressure at the end of the run.

Gph requires velocity and I get confused by internet math. In your case you will have plenty of supply. I would not use the PE. I would use the PEX for the main feed. PE will fail over time, in random ways. I have something like 1500 feet of 1" PE buried in my yard and I get to dig up the occasional pinhole, cut out and repair it. PEX is continuous and has standard hardware fittings from which you can then attach your local irrigation in a easier to maintain way. Of course this all assumes the main feed is buried. Plastics fail in the sun and weather fairly quickly unless made to purpose with weathering in mind so my suggestion of grey pipe was to that end.

Having said all that, pressure drops to the end of the line and you can have drip emitters at the end with reduced flow. This is harder. It is also one reason I suggested individual quick connects and multiple lines. In essence, the runs are shorter. Or you can slap together a line of emitters you can then feed from both ends if necessary to help balance the flow pressures. The point is design flexibility and maintenance.

I do not see how you will have too little supply, in fact you may want to use the half gallon emitters. I do not do drip irrigation so details like that type choice are not something I follow.

 

[Jeff Sheltman]

This is what I've come up with so far. It looks busy but I think the theory is correct. This includes all the tees and elbows as well as ball valves to isolate a certain area.

 

[DirtMechanic]

I would suggestyou preserve that image and then measure it against what you have in a few years that you might inform yourself. We have no standard to follow so I could never say anything about that image, except it looks like you are feeding the length but across is shorter (thus higher pressures).