Really basic drip irrigation

Build a simple system to water plants efficiently

Every summer starts the same way. In the spring, we plan, purchase, and plant our new seed and seedlings into pots, planters, and rich, brown raised beds. Then we water. At first watering is fun, especially when we're anticipating the first new shoots. After a couple weeks, reality sets in. Time is short, there's too much to do, and the plants still need to be watered. Weeds—plants out of place—are a never-ending problem and all that careful watering produced a bumper crop. The last straw is always the sticker shock that accompanies the first water bill of the summer.

At this point, we realize the only practical way to control our water consumption, reduce weeding, and provide ample water for our veggies and flowers without wasting a drop is to put in some kind of irrigation system. We dutifully head to the home improvement store and survey our options. There are hundreds of emitters, spikes, spray heads, tubing, and timers. Where in the world do you start?

There are a plethora o' advantages in having a drip irrigation system. First, it saves time ... lots of it. With a good quality timer, the system takes care of watering your plants, so regardless of how pressed you are for time, your plants won't have to pay the penalty. A few days of waterless stress during a warm spell and all those plants will croak overnight and your investment of time and money is lost. And you won't have to kick yourself for running out to do errands only to come home five hours later to a small flood plain. Finally, by putting water only where you want it reduces weeding significantly.

Make a plan

How big is your garden? What are you watering? Will you need to designate zones that require different amounts of water? Are you also doing containers or hanging baskets? Each pot or plant may have slightly different requirements.

The best way to start is by creating a plan. Create a rough drawing that accounts for the plants you want to water. Color code them with watering requirements ... don't worry about getting it absolutely right at this point ... you can swap out emitters if the 1/2 gallon per hour emitter doesn't do the trick and easily replace it with a 1- or 2-gallon emitter. Focus on the plan but don't get too hung up on details yet.

Indicate where the plants are (or will be).
Plan the route for your 1/2 inch "main" line. Make it as minimal as you can. It's less obvious that way. Add corners or T-connectors as needed. Run lines along the base of your house or along walkways to make them as inconspicuous as possible.
Plan your secondary lines (1/4") to individual plants from the main line.
Use colored pencils to code various parts of your plan. (You can also use a landscape planning software for this project.)

Regardless of the method you use to create your plan, make corrections on the drawing as they occur to you. You save yourself a lot of wasted time and parts. It's always better on paper than once you have the lines laid out and cut.

When you do this for the first time, it's often a good idea to start small with just the plants on the deck or a small herb bed. Once you get the hang of it, scaling it up to accommodate anything else you want to water is relatively simple.

Go shopping

Once you know what you how your system will be laid out, you can start making your shopping list.

The tools you'll need include a hammer, a good pair of shears, and a special hole punch for irrigation systems that can be found in the area of the home improvement store that has all the other irrigation supplies.

Manifold—Depending on your set up, you may need several optional faucet heads with adjustment to turn water on and off.
Timer—A good quality timer is going to pay for itself sooner than later. Don't waste energy replacing a lower quality timer every year. Get a good one and store it inside with your pruners when fall rolls around.
Backflow preventer or anti-syphon valve—Keeps water from running back into the household supply when water pressure drops.
Pressure regulator—Prevents high water pressure from damaging system. Two types are available: inline and adjustable.
Swival adapter
1/2" tubing—The polyethylene tubing can be installed either above or below ground. (For very large installations, 1" and 3/4" tubing is available. Fittings are NOT interchangeable to make sure your connectors are for the right size line.)
1/4" feed line micro tubing—
Various emitters—there are misters, directional sprayers, and different types of emitters for different per hour drip rates. (Generally, the larger the pot, the faster the drip rate should be.) Emitters can be inserted into either the mainline or the 1/4" micro tubing.
Connectors—Once you have a plan, you'll have a good idea of what types of connectors you'll need for your layout. They include corners, T-connectors, and straight connectors for both types of line.
Hose plugs and terminals—Plugs are for your mistakes and terminals are for the ends of the main lines.
Wire hold-down stakes (hair pins), clamps, and supports—Hair pins and clamps keep your main lines anchored to where you want them in the beds or along walls. Supports will raise drippers or sprayers up off the soil to do what they need to do.

Purchase about 15% more of the tubing, emitters, connectors, and plugs than you think you'll need, but save the receipt. If you tend to be very meticulous, you can plan exactly what parts you'll need, but you will still probably need a few extra parts to finish the job. Seems like it always takes a few more than you think and it's so much easier to have them than make yet another trip to get them. When the system is completely finished and everything works, keep a couple spares and return the rest.

Setting up your system

The faucet connects, in order, to the timer, the backflow preventer, pressure regulator (if needed), swivel adapter, and 1/2" main line.

Lay out your main lines and connect them according to your plan.
The hardest part of the project is inserting the barbed connectors into the feeder tubes. Just go slow and make sure you cut the feeder tubes long enough (but not too long) to reach your pots or plants. (Hint: You want the emitter as close as possible to the stalk of the plant to ensure that the water gets to the root system.)
Put an emitter on one end and connect the other to a barbed connector. Attach that to a main or branch line according to your plan. If you make a mistake ... and you will ... plug the hole with one of the hole plugs.
Once everything is connected, turn on the water. Check all the connections. Water should run clean. (If you are using a well system, you might want to attach a filter to screen out debris that might clog your system.)
Use wire hold-down stakes or clamps to anchor lines to the ground. Use c-clamps to fasten main line to walls or wood structures.
Cap or clamp off the terminal ends once everything looks like its working correctly.

Set the timer

As mentioned before, one good timer is worth six inexpensive ones. Read the manual first, then store it where you can find it again.

Set the timer to water as needed. Plan on resetting it according to the conditions as they change throughout the summer. As the days get longer and warmer, you'll probably need to increase watering times and durations. (Water early in the morning to maximize water uptake and minimize evaporation. And don't forget to mulch.)