WaterSmart irrigation comes in many different forms but can be described as the practice of applying water in an efficient manner where it’s needed, when it’s needed without contributing runoff into storm sewers, drainage ditches or waterways.
Scheduled irrigation systems, although convenient, are often the culprit of over-watering and runoff problems. Timers on scheduled systems should be turned off so that watering can be done when the grass and beds truly need watering. Then water thoroughly and deeply so that the ground is wet 6-12 inches deep. Sprinkler heads and hose end sprinklers should be directed a minimal distance from the ground and set to disperse water in large droplets rather than a misty-spray. This will reduce the amount of water lost to evaporation. Watering should be done during the early morning hours to avoid fungus development.
Low Volume Irrigation – LVI | By Angela Chandler, Harris County Precinct 2 Master Gardener
Low-Volume Irrigation (LVI) has been called by many names since its introduction to the market; “trickle irrigation”, “drip irrigation”, “micro-irrigation”, “micro-misting”, “low-pressure irrigation”. The term “low-volume irrigation” reinforces the idea of responsible water usage. This is how it will be referred to in the following information.
Several brands of systems have been available for a number of years and, like most technologies, have come a long way from just single emitters that distributed water drop by drop over a long cycle. In fact, these systems are continually improving, offering more efficient performance and a wider variety of components.
There are many products to choose from. A system can be customized for virtually every plant and condition. The following information is intended to teach you the basics and get you started, but you will find that you can become an “old pro” very quickly.
LVI vs. The Other Guys
There are many ways to get water to plants. The most efficient and productive are regular rains. Since plants seem to respond to rainwater better than anything else supplemental watering is often referred to as “life support” for plants. But in Houston we can count on lots of supplemental watering during certain seasons and during most years.
Hand-held hose watering is a relaxing and pleasant garden chore when compared to many other garden duties. However, hand watering can waste a lot of water and can be very time-consuming for a gardener with lots of area to cover.
The LVI advantage: Turn it on…go about your business…turn it off.
Soaker hoses work well, but are real water guzzlers in our soils. They must be placed fairly close together, or must be left on for long periods of time to soak a large area. Many times the area directly under the soaker hose is water logged, while the outer zone of the area is barely damp.
In addition, soaker hoses are not “garden remodeling” friendly. It will take two people to safely remove and re-lay soaker hoses in an established bed if the needs of the garden change or the hose is damaged.
The LVI advantage: Distributes directly to a specific area or plant, and can be modified within minutes without moving heavy hoses.
In-ground sprinkler systems use a lot of water. So much water is dispersed so rapidly that it often cannot soak in as fast as it is dispersed. In-ground systems have their place, they are efficient lawn and estate watering systems, but they may not be the answer for flower or vegetable beds and certainly not container plants.
In-ground sprinklers also require that the yard be trenched. The installation is expensive and not very “homeowner friendly”. Modifications can be costly and complicated as a garden matures and changes.
If you have an existing in-ground system, it CAN be retro-fitted for LVI in areas other than your lawn.
The LVI advantage: Where LVI is measured in GPH (gallons per hour), sprinkler systems are measured in GPM (gallons per minute). LVI does not require trenching and can be installed and modified inexpensively and infinitely.
LVI is Environmentally Friendly
It is important that we conserve all natural resources. Water is one of the most precious. It is also important that chemicals, fertilizers and nutrients – even “organic” products – stay in your yard where they can be used by your garden. Properly used, LVI seldom produces a run-off problem. This lessens the burden on our bayous, streams, estuaries, and bays.
How It Works
LVI distributes a measured amount of water over a specific period of time using a system of delivery and distribution pipes and application emitters. The systems are designed to maintain an evenly moist root zone.
Choosing a System
You can choose individual components or purchase a kit. However, you will outgrow using kits quickly and there is seldom any cost savings in buying kits. Most home centers carry one or more brands and a wide variety of components. Many of these components are interchangeable, but a few are not. Check before you leave the store.
Each manufacturer provides a brief installation manual. There is a lot of helpful information in these manuals; however, the “design” pages most often show a whole yard being run off one hose bib. This is intimidating to most beginners, giving the impression that you must design and install your entire yard in one system. In reality, not only is this impractical and unnecessary, it is impossible. Skip that page!
Getting Started
It’s actually easier to design your system once you understand how it is installed. Start with a small project, then graduate to a whole yard zoning and watering plan.
Design
Begin by breaking your yard or garden into “zones”. An example “zone” can be one garden bed or border.
Observe the types of plants growing in this zone and decide the type of emitter you want to use. For example, a bed of roses would be best served by adjustable drippers that do not spray water on the leaves. A bed of gingers might enjoy a summer drench from micro-sprinklers. A mixed border may use several different types of emitters.
Count the number of emitters required. Be sure you allow an “overlap zone” (25%) for micro-sprinklers. Make a list of their flow rates, which is printed on each package. If you total exceeds 200 GPH, you will have to break your “zone” into circuits. Tip: Micro-sprinklers have a higher flow rate (7-25 GPH) than drip emitters (1-10 GPH), and may require more “circuits”.
A single “circuit” should not exceed:
- 200 GPH
- 200’ of ½” poly-pipe header
Tools:
- A pair of scissors
- A punch tool (available with the other components)
- A pair of wire cutters (if you choose to recycle old shirt hangers as hold-downs)
Materials:
You will need these basic components:
- ½” Poly-Pipe (header)
- ¼” Feeder Tubing
- Hose End Fitting
- Figure 8 End Closure
- Goof Plugs
- Double Barbed Connectors
- Emitters:
- ¼” Porous Pipe
- ¼” Laser Drilled Pipe
- Punch-in Emitters
- In-line Emitters
- Micro-Spray Heads (available in various spray patterns)
- Drippers (available in fixed rate or adjustable rate)
- Spray Stakes
- Back-Flow Device
- Pressure Regulator (depending on type of emitter device)
- Hold Downs (or hangers if you are a recycler)
Installation
- Unroll the ½” poly-pipe and let it “relax” in the sun.
- Decide where your hose hook-up will be. This should be a position close to your water source. Attach the Hose End Fitting to this end of the poly-pipe.
- Lay out the poly-pipe. It can be hidden under mulch or tucked behind your order material or planting. If your poly-pipe needs to be pinned down, use recycled shirt hangers or purchase plastic hold-downs. Slide the Figure 8 Closure over the end of the poly-pipe, but do not close it off at this time. Begin installing the emitters. (It is often easier to place the emitter at the plant and work back to the poly-pipe).
- Slide one end of the ¼” feeder tubing over the barbed connector at the emitter. Set the emitter in place at the plant (it can be adjusted later).
- Run the tubing back to the poly-pipe (do not exceed 10’)
- Cut the tubing to length (leave a little extra)
- Insert one end of the double barbed connector into the ¼” tubing
- Using the punch tool, punch a hole in the poly-pipe (listen for the “snap”)
- Insert the other end of the double barbed connector into the ½’ poly-pipe (listen for the “snap”)
- Continue until all emitters are in place.
- Connect your water source. Allow the water to run until water flows from the end with the Figure 8 Closure. This will flush any small pieces of plastic, dirt, or mulch from the lines. Fold over the ½’ poly-pipe and slide the Figure 8 over the open end.
- Test your system. You can make adjustments at this time. If you determine there is a poor flow rate, make sure you have not overloaded your circuit. Add another circuit if required.
Maintenance & Repair
Winterizing Your System: Our normal winter conditions in Houston will not harm this system as long as it is drained. To drain, simply open the Figure 8 Closure. As soon as the water has drained from the system, re-close the Figure 8 to keep dirt and bugs out of your system.
Repairing Your System: Your system is easy to repair. Shovel or weed-eater damage to the ½” poly-pipe or the ¼” feeder tubing can be repaired by cutting out the damaged portion of the poly-pipe and installing a coupling (poly-pipe) or double barbed connector (feeder tubing). Damaged emitters can simply be replaced. Clogged emitters can be removed and flushed out, then replaced. If an emitter must be removed, just carefully pull it out and install a goof plug.
Beyond the Basics & Helpful Hints
Timers: Once the basic system is in place, there are many ways to tweak and fine tune it. One of the first things gardeners like to add is a timer. Timers will allow you to go on vacation and not come home to a very distressed garden or to keep a busy schedule without having your garden suffer from it. Timers that work on (2) 9-volt batteries and offer several watering cycles run $25.00 – $30.00.
Feeders: In-line feeders are available for tablets and feeding crystals. A venturi-type system can also be used.
Special Use Emitters: Several kinds of special use emitters are available including foggers. If you grow orchids, bromeliads, ferns, or other rainforest natives, they may benefit from foggers.
Creative Irrigation: A temporary and mobile misting system for rooting cuttings can be made up of LVI components and an inexpensive timer. A small greenhouse can be automatically watered with a similar set-up.
Quicker Connections: I highly recommend adding a quick disconnect fittings to make a gardener friendly product even more convenient. Install a male-end quick disconnect fitting on each end fitting on each circuit, and a female quick disconnect to the supply hose end. This will allow you to move from circuit to circuit with just a click instead of unscrewing the hose each time.
Flow Rate Adjustments: Many emitters are designed to be “pressure compensating”. However, some emitters are designed to work best at pressures lower than most municipal water systems. If this is the case with your choice of emitters, simply add a pressure regulator. This can be added at the hose bib or at the beginning of the circuit.
Slope Matters!: If you use drip emitters in slope situations, place more emitters with lower flow rates to avoid run-off and insure absorption.
Suggested Emitter Types, Rates, Placement
- Large Trees & Shrubs: 1 GPH per each 2-1/2’ of canopy. Use 1 or 2 GPH drip emitters or porous pipe placed evenly around drip line. Porous pipe can be added in “rings” spaced about 12” apart as the specimen grows.
- Small Trees and Shrubs: 1 GPH per each 2-1/2’ of canopy. Use 1 or 2 GPH drip emitters or porous pipe placed evenly 6” – 24” from trunk
- Roses, Azaleas, Camellias: Use adjustable drippers (1 – 10 GPH) at the base of the plant. Adjust flow rate by season & size.
- Flower Beds, Borders, Ground Cover Areas: Micro-Sprinklers spaced with 25% overlap zones
- Louisiana Iris Beds: Use ¼” porous tubing placed 12” apart off ½” poly-pipe header
- Vegetables in rows: Use ¼” laser drilled tubing placed along each row, or 12” apart in wide beds. Use ¼” in-line shut-off valves on each line.
- Tomatoes & Peppers: Use ¼” laser drilled tubing placed along each row or 1 GPH dripper at the base of each plant. These can be in-line emitters, punch-in emitters, or drippers on ¼” tubing branches.
- Container Gardens: Use (1) 1 GPH dripper for each inch of container size. Misters or foggers can be added on stakes for plants that enjoy high humidity.
Sprinkler Irrigation
Sprinkler irrigation – either a hose-end sprinkler or permanent underground – is the most common landscape watering method.
To maximize water use, make sure sprinkler heads are adjusted properly to avoid watering sidewalks and driveways. Adjust sprinkler head to spray large droplets – not a fog or fine mist – large drops are less susceptible to evaporation and wind drift. Water between late evening and mid-morning to avoid excessive waste of water through evaporation.
Drip Irrigation/ Soaker Hoses/ Gator Bags
- Drip Irrigation: Drip irrigation offers increased watering efficiency and plant performance compared to sprinkler irrigation. Drip irrigation slowly applies low-pressure water to soil through emitters, bubblers, or spray heads placed at each plant. Water applied by drip irrigation has little chance of waste through evaporation or run off.
- Soaker Hoses: Soaker hoses slowly apply water to the soil.
- Gator Bags: A gator bag is a large bag that can be used around the trunk of a newly-planted tree. It is filled with water which is slowly released around the tree for several hours.