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You’ve probably heard people singing the praises of drip irrigation, which was developed in the early 60s in Israel. I thought it was the greatest thing since sliced bread when it arrived on the scene during SoCal’s big drought in the late 70s. The idea is simple: water trickles out of a piece of tubing right next to the plant and soaks right into the root zone. No misting or overspray and minimal evaporation.

Simple or not, I haven’t been a big fan of this serpentine system for one reason--drip doesn’t keep up with the expanding root system.

Expandability: When plants get bigger, their root systems have to get bigger. But most people put a young one-gallon size plant in the ground, drop one emitter right above the root ball and assume that’s all they’ll ever need to do. Not so fast, buster.

If YOU were a Ceanothus griseus horizontalis ‘Yankee Point’ dreaming of growing ten feet across, you need a root system robust enough to support all the biomass above ground. So why would you send your roots out into dry soil when it’s nice and moist under that original drip emitter? I’d just hang back where the soil is cool and moist.

You’ve heard the phrase, "You can lead a horse to water..."? Same for the roots. If you don’t expand the drip system outward in concentrically wider circles, you can’t lead roots out where they need to be. The result? Stunted growth.

In-Line Technology
The innovation that corrects this problem is called "in-line drip tubing", manufactured by Netafim, Toro and a few other companies. The emitters are molded inside the tubing so all you see from the outside are predrilled, evenly spaced holes, usually at 12" or 18" apart.

The best use of in-line drip tubing for home gardens is a grid layout. Let’s say you want to plant a big area of your garden with a mix of shrubs, perennials and herbaceous ground covers arranged naturalistically in curves and drifts. Now imagine the pasta puzzle you’d create with traditional drip systems. Black tubes snaking and writhing hither and yon. Medusa comes to mind.

The magic of in-line is that the entire area within the grid gets evenly moist, allowing you to plant wherever you want. Just make sure all your plants are selected to thrive with about the same amount of water. 

Easy Peasy Set-up
We’re going to make a simple grid. Follow along with the graphic.

1) Outline the entire bed with a single strand of in-line tubing, creating a closed loop with one tee fitting leading back to the water valve, kind of like a lariat. 
2) Run parallel rows within the outlined area. If the predrilled holes in the tubing are 18 inches apart, your tubing grid will be evenly spaced at 18 inches. It ends up looking like a sheet of notebook paper with neatly drawn lines within.
3) Offset the pre-drilled tubing so that the in-line emitter locations create a triangular pattern.

The magic of this system is that you end up with water evenly distributed everywhere. This allows you to plant whatever you want wherever you want without having to snake tubing all over the place.

One more thing. Although most in-line tubing can be installed below ground, I suggest leaving on top of the soil and covering it will a 3" deep layer of wood chips. That prevents ultraviolet rays from harming the pipe, hides the industrial look and gives you all the soil-building benefits of organic mulch.

As much as I enjoy imparting useful information about water conservation and sustainability, my inner Dave Barry is clawing to get out. Next up, what happens when Microsoft decides to "interface" with your veggie plot?

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