Emitter Tubing Spacing for Irrigation

Hi, all!  I am progressing in making my raised beds for my start at SFG.  To review what I have done so far.  Prepped a 10'X30' area, put down weed barrier, put together and oiled 3 ea, 4' W X 6' L X 7.25" T cedar beds supports from Gardners Supply, removed a 3' X 5' rectangle of weed barrier in each bed and replaced that space with cardboard, made up & placed in the beds 38 ft3 (started with 36 ft3, added 2 ft3 more after it settled) of Mel's Mix using 5 different composts, peat moss & coarse vermiculite (what a job that was) and just got done installing the 1/2" water feed line for irrigation.  

Now to the final part of installing drip irrigation.  I have and desire to use 1/4", 6" spacing, 0.52 gph drip irrigation that I plan to place from the header on each raised bed.  The main purpose for these raised beds for the 2020 growing season is for corn.  Based on this and being in a dry, higher altitude climate (5b) what is the suggested spacing for the emitter tubing?  I see Sanderson has hers emitter tubing placed based on a 6" X 6" grid for emitter spacing. For my install that would be 6 rows spaced at 6" of 1/4" tubing, 6' long.  I like that idea but I am open for suggestions.

BTW, I would post some pictures if I can only figure out how to post them.

MarkBroomfield wrote:
BTW, I would post some pictures if I can only figure out how to post them.

Sounds like you are making good progress (see note at bottom on posting pictures).  When I installed drip irrigation last year for all of my raised beds, I used 1/4" dripline 9" spacing, and each dripline spaced 10" apart. I learned from experience that was too much space between drip emitters to get a good ground soaking.  So, this year I re-did all of the beds. I replaced the 9" dripline with 6", and I changed them from 10" between driplines to 8".  Working much better, and the plants are responding well. This is one of the beds with the newly spaced driplines.


 

If you haven't already done so, check out Dripworks Resources page for a lot of good info on drip irrigation:  https://www.dripworks.com/resources


Posting pictures is fairly easy.  On the above menu line, click on the "Host an Image" icon:




Then, click on the "Select Files" icon.



When that window opens, go to the directory on your computer with the images you want to post.  You can select up to 3 images at a time.  After you post the 3 pictures, you can click on "Remove All", and then select 3 more images.

Below are my pictures of my SFG before I add the tubing emitters:

Mark, You have done a beautiful job so far! If you are going to do SFG, I would make the grids before working on the drip lines. That will insure that each line is really where you want it. For a 4'x6' bed, I would recommend making two (2) 2'x3' grids for ease of removing without breaking, amending one half of the bed, etc.

The largest bed I have is 2' x 8' and the drip lines are 2' long each. One thing is to make sure the linear footage of the 1/4" lines doesn't exceed the pressure limitations. If I could do things over, I would run the solid 1/2" tubing either across the end or down the length of the bed and then tie in the 1/4" drip lines to it.

Yes, my drips are 4/square, 6" apart.

Believe it or not, but I am finally trying to install drip irrigation in my garden.  It has been 7 years of hand watering and this year with almost no rain has pushed me over the edge.  The irrigation company that supplies our irrigation for the grass yard close to the house installed lines leading to each bed and a timer system that only runs the irrigation in my vegetable garden.  They also ran a 1/2" blank tube down each of my 7 rows of beds.  So I have to set up the drip irrigation in each bed. 

My question is - what is the purpose of using 1/4 inch drip tubing down the row in a bed instead of 1/2 inch drip tubing.  For instance, Ohio Gardener mentions 1/4 inch drip tubing down the length of the rows.  Why not use 1/2 inch drip tubing down the rows.  I do know that you can get 6 inch spacing of emitters on the 1/4 inch tubing and the lowest I could find for 1/2 inch drip tubing was 9 inch spacing.  

I have already run drip system to my potted plants.  I moved them all into one row (mostly).  I ran 1/2 inch blank tubing down the row, then  1/4 inch tubing up to the top of the pot, then 1/4 inch drip tubing circling the pot.  Also installed a cut off valve on each pot so I could stop watering that individual pot when nothing was growing in it.

I also set up my garlic bed.  With 1/2 inch blank tubing down the length of the bed and 1/4 inch 6 inch emitter tubing every 12 inches across the bed.  If 12 inch separation of the 6 inch drip tubing does not work out, then I can add more 1/4 inch emitter tubing.

Yolos, the size of the tubing is determined by the desired flow rate. Most raised bed gardens want a slow flow rate of the emitters, such as 0.5 gph, with enough time for the water to soak into the soil and not run off.  Some soils, though, such as sand require much higher flow rates, such as 2.0 gph - that high flow rate would need a 1/2" tube and emitters.  It is all about what is needed for the gardens.

If you haven't already done so, check out the Dripworks Drip Planning Guide.

Yolos, Do you have more than 1 auto system line dedicated for the garden? It seems to me that a solid 1/2" line down just one row of your huge garden would be the max you could run at one time. An auto value at the start of each row or a ball valve at the start of each row where you manually open to just one row at a time. ??

sanderson wrote:Yolos, Do you have more than 1 auto system line dedicated for the garden?  It seems to me that a solid 1/2" line down just one row of your huge garden would be the max you could run at one time.  An auto value at the start of each row or a ball valve at the start of each row where you manually open to just one row at a time. ??

Thanks Sanderson and OhioGardener.

The company that maintains the irrigation system in our "manicured" Bermuda grass area set the bones of the system up for me and gave me some suggestions.  I divided the garden into 4 zones and there is a PVC line run into the garden for each of the 4 zones.  That means that every two rows of beds are on a single zone and therefore I can control each zone independently.  Also, for each row of beds, I am installing a shut off valve.  And on each bed I am installing a shut off valve.  This gives me pretty good control over the watering.  They put in a controller that I can water 4 different cycles based on how I want each area watered (length of time to water and on what days).

They ran 1 inch PVC lines to the beginning of each row.  Then 1/2 tubing down the outside of each row.  Now it is my responsibility to run the irrigation into each bed and install shut off valves.   So far I have run irrigation to two beds.  I also lined up all of my pots into a T shape and now have irrigation to about 20 pots.  Unfortunately, there is a major leak in the lawn irrigation system and we had to turn off the whole system.  Therefore, I have not been able to test my irrigation installation yet.  I don't want to get too far ahead until it is actually tested.

yolos wrote:

sanderson wrote:Yolos, Do you have more than 1 auto system line dedicated for the garden?  It seems to me that a solid 1/2" line down just one row of your huge garden would be the max you could run at one time.  An auto value at the start of each row or a ball valve at the start of each row where you manually open to just one row at a time. ??

Thanks Sanderson and OhioGardener.

The company that maintains the irrigation system in our "manicured" Bermuda grass area set the bones of the system up for me and gave me some suggestions.  I divided the garden into 4 zones and there is a PVC line run into the garden for each of the 4 zones.  That means that every two rows of beds are on a single zone and therefore I can control each zone independently.  Also, for each row of beds, I am installing a shut off valve.  And on each bed I am installing a shut off valve.  This gives me pretty good control over the watering.  They put in a controller that I can water 4 different cycles based on how I want each area watered (length of time to water and on what days).

They ran 1 inch PVC lines to the beginning of each row.  Then 1/2 tubing down the outside of each row.  Now it is my responsibility to run the irrigation into each bed and install shut off valves.   So far I have run irrigation to two beds.  I also lined up all of my pots into a T shape and now have irrigation to about 20 pots.  Unfortunately, there is a major leak in the lawn irrigation system and we had to turn off the whole system.  Therefore, I have not been able to test my irrigation installation yet.  I don't want to get too far ahead until it is actually tested.

Yea, they just fixed the leak in the lawn irrigation system so I got to run the drip irrigation in the garden in the beds that I have set up so far.  Worked like a charm.  I will have to keep adding drip irrigation to the rest of my beds over the fall and winter.  This coming year will be a test.  I  am using some 1/2 inch drip in some beds and 1/4 inch in other beds.  We shall see which works best in my garden.   Then I will be all set for another rainless summer.

Oh, good, you have 4 Zones on automatic, with multiple valves for diverting!