Q. I’m installing a drip irrigation system and to save some money, I decided to buy inch wide black tubing. I used a hot needle to make some small holes every 27 inches apart from each other, but when doing water pressure testing , some holes emit more water than others. What do you recommend in this case? Is it a bad idea to punch my own holes? Or is there a way to do this with an even result in each hole?
A. Just punching holes doesn’t work well, as you discovered. It’s almost impossible to get the holes uniform in size, and even if you did, variations in the water flow patterns inside the tube would make each hole emit water at a different rate. The solution is simple. You need to install barbed drip emitters in the holes. The drip emitters are small, plastic, highly-engineered devices that regulate how much water comes out, so that each hole gives a very uniform rate of flow. A typical emitter (sometimes called a dripper) is about the size of 5 dimes stacked on top of each other. The emitter has a barbed inlet on one side that pushes into the holes in the tube. You just snap the barb into a hole punched in the tube. Then the water drips evenly out of an outlet hole on the other side of the emitter. You need one emitter for each hole. Emitters are typically sold in packages of 10, 25, 50, or 100 emitters per package.
Since you already bought tube, cut off a small piece of your tubing that has a hole in it and take it with you to the store. 1″ black tube is probably not made for use with drip systems. It probably has a thicker wall than standard drip system tubing, so the barbs on some brands of emitters may not be long enough to push all the way into the tube and lock in place. Most brands should work, but in your case it would be best to test it at the store so you don’t have to make another trip back to the store if the emitters don’t fit. The emitter’s barb should push all the way in and lock the emitter onto the tube. It should not easily pull out.
It might be a good idea for you to read the Drip Guidelines at http://www.irrigationtutorials.com/drip-irrigation-design-guidelines-basics-of-measurements-parts-and-more/ . There are a lot more mistakes you can make, and I’d hate to see you waste any more of your time and money.